Ion Mobility Filter Electrodes with Straight-Walled MEMS Channels
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Solution Overview
Problem
Existing methods for manufacturing MEMS ion mobility filters face limitations due to tapering in the ion channels, which restrict the aspect ratio and performance, leading to reduced ion filtration efficiency.
Innovation Solution
Mechanical dicing is used to form ion mobility electrodes, allowing for higher aspect ratios and preventing tapering, with each electrode being separate and attached to the support, enabling the creation of channels with aspect ratios of at least 10:1 and widths between 10 and 50 microns, and the use of conductive layers for electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If etching is used to form ion channels, then the manufacturing process is simple, but the ion channels become tapered which limits the aspect ratio and reduces ion filtration efficiency
Solution Approach 1:
The patent replaces the chemical etching process with a mechanical dicing process to form ion channels. By using a dicing saw to mechanically cut the electrode layer, the method achieves straight-walled channels with high aspect ratios (at least 10:1) without the tapering effect inherent in etching processes. This mechanical substitution resolves the contradiction by maintaining manufacturing simplicity while dramatically improving channel geometry precision.
2Ease of manufacture
If etching is used to form ion channels, then the process is straightforward, but the channel width reduces at one end which limits ion transmission
Solution Approach 1:
The patent substitutes mechanical dicing for chemical etching to form ion channels. The dicing process creates channels with uniform width throughout their length, eliminating the tapering that reduces ion transmission in etched channels. This allows ions to pass through the full width of the channel without being Funnelled into a narrower exit, thereby improving ion transmission efficiency while keeping the manufacturing process straightforward.
3Ease of manufacture
If conventional manufacturing methods are used, then the process is established, but electrode shifting occurs over time which reduces filter performance
Solution Approach 1:
The patent segments the electrode layer into individual electrodes using mechanical dicing, creating physically separated electrode structures. Each electrode is independently supported by the substrate, preventing lateral movement and shifting over time. This segmentation approach maintains the simplicity of established manufacturing processes while dramatically improving electrode stability and long-term filter performance.
Data Source
AI summary
The present techniques relate to methods of manufacturing MEMS gas sensors, for example, an ion mobility filter which may be used as a field asymmetric ion mobility spectrometry filter. The method comprises a step of providing a support with an aperture (S300, S302) and forming electrical connections (S304) in the support. The method also comprises steps of attaching an electrode layer to the support (S306) so that the electrode layer covers the aperture and forming a plurality of ion mobility electrodes (S308) by mechanically dicing through the electrode layer. Each adjacent pair of electrodes defines an ion channel between them and each electrode is separate from the adjacent electrode(s).