MEMS 3D Diaphragm Electrode Composite Structure
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Solution Overview
Problem
Conventional MEMS microphone structures require complex multi-layer metal etching processes, resulting in a less robust structure that is not adequately designed to handle mechanical stress from sound waves.
Innovation Solution
A 3D diaphragm electrode with a composite structure, featuring a dielectric layer between metal layers and a tapered trench design, which enhances mechanical strength and eliminates the need for etching a metal layer, simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional multi-layer metal etching process is used to form micro-machined metal mesh, then the structure can be formed, but the manufacturing process becomes complex and the mechanical strength is insufficient
Solution Approach 1:
The patent applies composite materials by forming a 3D diaphragm electrode with a composite structure consisting of a first metal layer, a dielectric layer, and a second metal layer. This composite structure enhances the mechanical strength of the diaphragm electrode while simplifying the manufacturing process, as it eliminates the need for complex multi-layer metal etching while providing robust structural integrity to handle mechanical stress from sound waves.
2Ease of manufacture
If multiple metal layers are etched to form micro-machined metal mesh, then the MEMS structure can be formed, but the manufacturing process requires multiple etching steps increasing process complexity
Solution Approach 1:
The patent applies the extraction principle by removing the complex multi-layer metal etching steps from the manufacturing process. Instead of etching multiple metal layers to form micro-machined metal mesh, the invention uses a simplified approach where metal layers are deposited conformally on sacrificial layers, and the sacrificial layers are removed to form suspended 3D diaphragm electrodes, thereby eliminating multiple etching steps and simplifying the manufacturing process.
Solution Approach 2:
The patent applies preliminary action by depositing sacrificial layers (first, second, and third sacrificial layers) before depositing the metal layers. These sacrificial layers are prepared in advance to define the eventual shape and position of the 3D diaphragm electrode. By having these sacrificial structures in place beforehand, the subsequent metal deposition and removal processes become simpler and more straightforward, reducing overall process complexity.
Data Source
AI summary
A micro electro mechanical system (MEMS) structure is disclosed. The MEMS structure includes a backplate electrode and a 3D diaphragm electrode. The 3D diaphragm electrode has a composite structure so that a dielectric is disposed between two metal layers. The 3D diaphragm electrode is adjacent to the backplate electrode to form a variable capacitor together.