n IFPAC 2003 n Dr Berthold Andres n
n IFPAC 2003 n Dr. Berthold Andres n ABB Automation Products Germany © Copyright 2002 ABB. All rights reserved. - n Microelectromechanical Systems for Process Analytics
© Copyright 2002 ABB Automation - 3 - Agenda n What are Microelectromechanical Systems (MEMS) n Why use MEMS technology for process analytical n ABB MEMS Projects n Summary
What are Microelectromechanical System? n Microelectromechanical System (MEMS) is a miniaturization technique based upon silicon wafer technology. n This technology is a departure from the historical emphasis on the miniaturization of existing electrical, optical and mechanical assemblies © Copyright 2002 ABB Automation - 4 - èExamples
Why use MEMS in Process Analytical? Small is beautiful !! Size effects: © Copyright 2002 ABB Automation - 5 mm n Cost of manufacturing n Cost of Installation n Analyzer Location n Sampling systems n Shelters
Why use MEMS in Process Analytical? n © Copyright 2002 ABB Automation - 6 - n Manufactured in silicon wafer processes n Highly reproducible n Lower manufacturing cost for larger quantities n Significantly smaller sizes n Less consumables longer time of operation n Lower power demand n n Portability n Installation at the source Faster response time possible n Smaller dead volume n Lower mass n Shorter diffusion length n Designed as integrated assemblies n Further reduced size n Reduced number of components n Reduced integration time n Faster cycle time Exchangeability of complete subassemblies n Maintenance is simplified
Where to use MEMS in Process Analytical? n Two Types of MEMS Projects n © Copyright 2002 ABB Automation - 7 - n Analyzer Components n Moderate Risk, High Reward n Detectors, Valves, columns, ionization chambers, …. Complete MEMS Analyzers n High Risk, High Reward n GC, MS, Titration, ….
1994: Our first introduction of a MEMS sensor n Development of a Thermal Conductivity Detector (TCD) for gas analysis (e. g. Hydrogen in air, CO 2 in air) Conventional MEMS design © Copyright 2002 ABB Automation - 8 - 100 mm n Designed as an integrated detector with n Thin-film measuring resistor n Thin-film reference resistor n Membrane to control gas flow through detector n Size ~ 2 sq mm n Housing and electronics are added in the next step 10 mm
© Copyright 2002 ABB Automation - 9 - Thermal Conductivity Analyzer, Summary n Development was a big success Several thousands sold since introduction n Drivers for success n n Size of TCD detector can be minimized without loosing sensitivity n Better technical data because of smaller size n Smaller thermal capacity of detector n Faster response time n We already knew the application from our standard detectors n “Simple” design of the detector. Housing and pneumatical connections are added in another production process n Market size is just large enough for the MEMS production Current drawback n It is difficult to control the production process for small quantities over a longer period of time (thousand is still a small number for a MEMS process)
© Copyright 2002 ABB Automation - 10 - Realization of Micro GC with MEMS Components
Micro-Valve © Copyright 2002 ABB Automation - 11 - n Technical Specifications n Micro ball valve n Electromechanically activated n Ball size ~ 500 µm n Plasma etching to get high precision valve seat n Pressure range < 2 bar n Power consumption < 300 m. W
Micro Valve Array is required for Micro-GC n Integration of multiple micro ball valves © Copyright 2002 ABB Automation - 12 - => Realization of dedicated flow schemes n Summary n Micro ball valves can be produced n But: Production of micro ball valve arrays is very complex, overall yield is too low
Micro Flame Ionization Detector for Micro-GC © Copyright 2002 ABB Automation - 13 - n Designed as an integrated detector n silicon-glass technology n integrated sample injection system n integrated gold electrodes n quartz capillary connectors 5 mm MEMS design Conventional design
© Copyright 2002 ABB Automation - 14 - Flame Ionization Detector, Summary n Micro-FID has been built and is running n Micro-FID shows typical problem of MEMS technology that not everything can be simply scaled down n Quenching distance between flame and electrodes does not allow to reduce size of flame substantially Current Micro FID has no substantial benefits compared to conventionally manufactured system
MEMS Thermal Conductivity Detector for Micro-GC Advantages: • Small Thermal Capacity • Small Dead Volume © Copyright 2002 ABB Automation - 15 - 1 mm Fast Response Time < 10 ms Low Detection Limit < 10 ppm
© Copyright 2002 ABB Automation - 16 - MEMS GC, Summary n Single components can be successfully designed n Complete GC n Very complicate to go from prototypes to production n Each component must be developed and trouble shot as an individual n The integration of individual components is a second project and very complicated n GC Market Volumes are not compatible with MEMS
Next step: Concept for Micro-Mass-Spectrometer © Copyright 2002 ABB Automation - 17 - Target: MMS with the size of a cellular phone Separator with 1 mm length Plasma Ion source No UHV required !
© Copyright 2002 ABB Automation - 18 - MEMS Mass-Spectrometer, Objectives n Measuring principle or component must be scalable ok for MS n Concentrate on crucial parts of the system design where the MEMS technology can show all its advantages e. g. mass separator n Yield for MEMS processes, especially for difficult structures, is not always 100 % MEMS should be split to several components which can be tested individually
© Copyright 2002 ABB Automation - 19 - MEMS Conclusions n ABB has been successful at targeting analyzer components for the conversion to MEMS technology n Success comes from the use of MEMS components in conventional or miniature systems n Total integrated MEMS systems may require too much time to get out of the lab and become a real product
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