MEMS Microphone Radial Etch Channels for Capacitive Pressure Measurement
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Solution Overview
Problem
Existing microelectromechanical devices for capacitive fluid pressure measurement face challenges in manufacturing efficiency and accuracy due to complex etching processes and potential parasitic capacitance issues.
Innovation Solution
The device incorporates a counter electrode with radial etch channels that simplify the manufacturing process by improving etchant distribution and homogenization, while also reducing parasitic capacitance through a clearance channel design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used without radial etch channels, then the etching process is simpler to design, but etchant distribution is poor and etching homogeneity is reduced
Solution Approach 1:
The counter electrode is segmented by introducing multiple radial etch channels that divide the electrode structure into radial sections. This segmentation allows etchant to access and distribute uniformly across the entire electrode surface, improving etching homogeneity while the channels themselves become integral parts of the electrode design
Solution Approach 2:
The counter electrode is designed with a porous-like structure featuring multiple radial channels that extend through the electrode thickness. This channel network enables thorough etchant penetration and distribution, achieving uniform etching throughout the electrode material while maintaining the electrode's functional integrity
2Reliability
If membranes are mechanically coupled without clearance channels, then structural stability is improved, but parasitic capacitance increases
Solution Approach 1:
A clearance channel is extracted or removed from the region between the membrane and counter electrode. This creates a gap that eliminates the parasitic capacitance path while the membrane remains mechanically coupled to the counter electrode through other means, thus removing the harmful capacitive effect without compromising structural stability
Solution Approach 2:
The clearance channel acts as an intermediary space that electrically isolates the membrane from the counter electrode, preventing parasitic capacitance formation. This intermediate gap allows the membranes to be mechanically coupled through alternative pathways while maintaining electrical separation to eliminate harmful capacitance
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 design enhances manufacturing efficiency, reduces parasitic capacitance, and improves measurement accuracy by allowing for better etching control and defined capacitance measuring ranges.
Implementation Method 1
a first membrane (2) and a second membrane (3) which can be elastically deflected by a fluid pressure
Implementation Method 2
an etch channel can be formed during manufacture of the device, for example, by a hollow volume in at least one material layer of the device
Implementation Method 3
a microelectromechanical device for capacitive fluid pressure measurement
Data Source
AI summary
A microelectromechanical device for capacitive fluid pressure measurement. The device has a first membrane and a second membrane which can be elastically deflected by a fluid pressure, wherein a cavity is formed between the first membrane and the second membrane, in which cavity a counter electrode is arranged, wherein the counter electrode has a plurality of radial etch channels which extend radially from the center of the counter electrode to an edge of the counter electrode. A microelectromechanical microphone, and a method for producing a microelectromechanical device, are also described.