Double-Membrane MEMS Component With Filled Etch Access Openings
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Solution Overview
Problem
Acoustic MEMS sensors, such as MEMS microphones, are vulnerable to contaminants like particles and moisture, which can lead to malfunction or reduced performance, and existing protection methods can impair their acoustic behavior.
Innovation Solution
A double-membrane MEMS component production method involving a layer arrangement with a first membrane structure, a sacrificial material layer, and a counterelectrode structure, where through openings are formed and filled with different materials to create mechanical connection elements that are hermetically sealed and decoupled from the counterelectrode, allowing for effective mechanical and electrical protection while maintaining high signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex grilles and special ports are used to protect acoustic MEMS sensors from contaminants, then reliability is improved, but acoustic behavior is impaired
Solution Approach 1:
A sacrificial material layer is introduced as an intermediary between the first membrane structure and the counterelectrode structure. This layer can be selectively removed through etch access openings to expose specific regions while maintaining protection in other areas, thus achieving both contamination protection and preserved acoustic behavior through selective exposure
Solution Approach 2:
The protective structure is segmented into different regions: covered regions where the sacrificial material remains to provide contamination protection, and etch access openings where the sacrificial material is removed to maintain acoustic performance. This segmentation allows different functional requirements to be satisfied in different spatial locations
2Strength
If through openings are formed in sacrificial material layer to expose filling material structure, then mechanical connection is achieved, but structural complexity increases
Solution Approach 1:
The filling material structure is applied to the first membrane structure before the sacrificial material layer is completely removed. This preliminary action ensures proper mechanical coupling and positioning, simplifying the subsequent etching process and reducing overall production complexity
Solution Approach 2:
The filling material structure serves as an intermediary mechanical connection element between the first and second membrane structures. It provides the necessary mechanical coupling while being accessible through selectively removed sacrificial material, achieving strong connection without complex direct bonding processes
3Strength
If multiple filling material layers are applied in the through opening, then mechanical connection strength is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple filling material layers with different properties are applied in the through opening to create a composite structure. This provides enhanced mechanical connection strength through material diversity while maintaining ease of manufacture by using standard sequential deposition techniques
Solution Approach 2:
Different filling material layers are applied to provide different local properties: some layers may provide structural strength, others may provide adhesion, and others may provide etch resistance. This local differentiation optimizes mechanical connection strength without requiring complex manufacturing processes
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
The method results in MEMS components with excellent acoustic behavior, improved signal quality, and enhanced mechanical protection, with flexible mechanical connection elements that are resistant to etchants and can be easily integrated into existing production processes.
Implementation Method 1
a step of removing the sacrificial material is carried out by means of an isotropic etching process using a liquid or gaseous etchant or reactant
Implementation Method 2
forming a filling material structure in the through opening by applying a first filling material layer on the wall region of the through opening
Data Source
AI summary
A production method for a double-membrane MEMS component includes: providing a layer arrangement on a carrier substrate, wherein the layer arrangement comprises a first membrane structure, a sacrificial material layer adjoining the first membrane structure, and a counterelectrode structure in the sacrificial material layer and at a distance from the first membrane structure, wherein at least one through opening is formed in the sacrificial material layer as far as the first membrane structure; forming a filling material structure in the at least one through opening by applying a first filling material layer on the wall region of the at least one through opening; applying a second membrane structure on the layer arrangement with the sacrificial material; and removing the sacrificial material from an intermediate region to expose the filling material structure in the intermediate region.