Monolithic Ion Filter Electrodes for IMS
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Solution Overview
Problem
Existing ion filter manufacturing methods require an insulative substrate, which complicates the process and is not suitable for microchip implementations, especially due to issues like molecular diffusion and high voltages in field asymmetric ion mobility spectrometry.
Innovation Solution
A monolithic structure is used to form ion filters, where electrodes are created from a single wafer material like silicon, with mechanical connections providing electrical separation, eliminating the need for a substrate and allowing for direct etching of channels and electrodes within the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional microfabrication techniques with insulative substrate are used, then electrodes can be manufactured with good electrical separation, but the manufacturing process becomes complex and requires multiple bonding and etching steps
Solution Approach 1:
The invention extracts and removes the insulative substrate from the device structure. Instead of using a separate substrate to provide electrical separation, the electrodes are formed directly on a support surface, and electrical separation is achieved through the electrode geometry and spacing itself, eliminating the need for substrate bonding and multiple fabrication steps
Solution Approach 2:
The invention merges the support surface with the electrode structure by forming electrodes directly on the support surface. This integration eliminates the separate substrate layer and reduces the overall device complexity while maintaining the necessary electrical separation through the electrode design
2Manufacturing precision
If paired interdigitated electrode structures are used with mechanical separation on insulating substrate, then ions can be selectively filtered, but additional etching steps and substrate processing are required
Solution Approach 1:
The support surface is prepared in advance with the necessary surface properties to directly receive and bond the electrode structures. This preliminary preparation eliminates the need for subsequent substrate bonding steps and complex multi-step etching processes, streamlining the manufacturing workflow
Solution Approach 2:
The device is segmented into modular components (electrodes and support surface) that can be independently fabricated and then assembled. This segmentation allows for simpler, more efficient manufacturing of each component separately, reducing the overall complexity and improving productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method simplifies the manufacturing process, reduces the need for additional etching steps, and enables the production of ion filters with controlled electrical impedance, suitable for use in ion mobility spectrometers and pumps, while maintaining effective ion channel formation.
Implementation Method 1
the connecting portion of the structure provides a higher electrical impedance than the filter would provide without such a mechanical connection, to thereby electrically separate the electrodes
Implementation Method 2
selectively removing regions of the structure, to form a pair of electrodes defining at least one ion channel therebetween
Data Source
AI summary
An ion filter (10) for use in ion mobility spectrometry is described, together with a method for manufacturing the filter. The filter (10) is manufactured by removing portions from a monolithic structure to form a pair of electrodes which remain mechanically connected. The connecting portion (22) provides sufficient electrical impedance between the electrodes to effectively electrically separate the electrodes. The connecting portion may be doped or chemically modified to obtain a desired impedance, or this may be obtained through appropriate selection of physical dimensions.