MEMS Microphone Backplate Acoustic Hole Array for Etching Stability
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Solution Overview
Problem
The existing MEMS microphone fabrication process faces challenges with non-uniform etching of the dielectric material due to the mechanical intensity variations during the etching process, which can lead to instability and potential damage to the diaphragm.
Innovation Solution
A MEMS microphone structure with a backplate layer featuring a regular array pattern of acoustic holes, such as a hexagon unit, ensures uniform etching conditions by distributing acoustic holes uniformly, allowing for consistent mechanical intensity and efficient removal of the dielectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a relatively large amount of dielectric material between the diaphragm and the backplate layer is removed through acoustic holes, then the diaphragm can be released, but the etching process takes a long time and may cause instability
Solution Approach 1:
The backplate layer is segmented into multiple acoustic holes arranged in a regular array pattern, dividing the etching task into multiple parallel pathways. This segmentation allows the etching process to remove dielectric material more efficiently through distributed holes while maintaining uniform mechanical intensity across the etching front, thus reducing total etching time while preserving process stability.
Solution Approach 2:
The acoustic holes are arranged in a regular array pattern with specific geometric configurations (such as hexagonal patterns with central and peripheral holes at defined distances). This creates localized etching zones with controlled mechanical intensity distribution, ensuring uniform etching conditions across different regions of the dielectric layer, which stabilizes the etching process while maintaining efficient material removal.
2Manufacturing precision
If the dielectric material is removed through acoustic holes in the backplate layer, then the diaphragm is released, but the mechanical intensity of dielectric material may be non-uniform causing etching instability
Solution Approach 1:
The acoustic holes are arranged in a regular array pattern with specific geometric configurations (such as hexagonal patterns with central and peripheral holes at defined distances). This creates localized etching zones with controlled mechanical intensity distribution, ensuring uniform etching conditions across different regions of the dielectric layer, which stabilizes the etching process while maintaining efficient material removal.
Solution Approach 2:
The regular array pattern of acoustic holes creates a more uniform mechanical intensity distribution across the dielectric layer during etching. By strategically positioning holes in a symmetric pattern with equal spacing, the stress and mechanical intensity are evenly distributed, creating equipotential conditions that prevent localized variations in etching rate and ensure consistent etching depth and quality across the entire structure.
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 approach stabilizes the etching process, ensuring uniform etching of the dielectric layer and reducing the risk of diaphragm damage, thereby improving the reliability and efficiency of the MEMS microphone fabrication.
Implementation Method 1
The removing the dielectric material, the etching process would etch the dielectric material through the acoustic holes in the backplate layer
Data Source
AI summary
The invention provides a MEMS microphone. The MEMS microphone includes a substrate, having a first opening. A dielectric layer is disposed on the substrate, wherein the dielectric layer has a second opening aligned to the first opening. A diaphragm is disposed within the second opening of the dielectric layer, wherein a peripheral region of the diaphragm is embedded into the dielectric layer at sidewall of the second opening. A backplate layer is disposed on the dielectric layer and covering over the second opening. The backplate layer includes a plurality of acoustic holes arranged into a regular array pattern. The regular array pattern comprises a pattern unit, the pattern unit comprises one of the acoustic holes as a center hole, and peripheral holes of the acoustic holes surrounding the center hole with a same pitch to the center hole.