Dual-diaphragm MEMS Microphone Manufacturing via Parallel Processing
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Solution Overview
Problem
The manufacturing process of MEMS microphones is inefficient due to the sequential nature of each process step on a shared silicon base, limiting the production efficiency of dual-diaphragm structures.
Innovation Solution
A method for manufacturing a dual-diaphragm MEMS microphone structure involving a semiconductor base with a capacitance system, where a supporting part connects two vibrating diaphragms with a back plate, allowing for independent processing and integration of components using semiconductor processes like bulk-silicon etching and deposition techniques, and forming a releasing hole to eliminate internal oxidation layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If all process steps are conducted on the same silicon base sequentially, then manufacturing precision is maintained, but productivity decreases
Solution Approach 1:
The patent divides the manufacturing process into two independent parallel lines: a first manufacturing line that forms the first vibrating diaphragm structure on the first surface of the silicon base, and a second manufacturing line that forms the second vibrating diaphragm structure on the second surface of the silicon base. This segmentation allows both diaphragm structures to be manufactured simultaneously rather than sequentially, thereby improving productivity while maintaining manufacturing precision through dedicated process steps for each line.
2Device complexity
If sequential processing is used on shared silicon base, then device complexity is reduced, but productivity decreases
Solution Approach 1:
The patent segments the dual-diaphragm structure into two independently manufacturable parts: a first vibrating diaphragm formed on the first surface and a second vibrating diaphragm formed on the second surface. Each diaphragm can be processed through its own sequence of steps (forming, etching, releasing) without interfering with the other, allowing parallel processing that improves productivity while keeping each individual manufacturing sequence relatively simple.
Solution Approach 2:
The patent utilizes the third dimension by forming structures on both the first surface and second surface of the silicon base simultaneously. Instead of stacking processes vertically in sequence on one surface, the manufacturing moves to another dimension (the opposite surface of the base), enabling parallel processing paths that increase productivity without significantly increasing the complexity of individual process sequences.
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 enhances manufacturing efficiency and allows for consistent external pressure on diaphragms, facilitating easier integration with other semiconductor devices while maintaining high performance and miniaturization.
Implementation Method 1
etching steps to form a cavity between the first and second vibrating diaphragms
Implementation Method 2
semiconductor processes like bulk-silicon etching
Data Source
AI summary
The invention provides a method for manufacturing a MEMS microphone, including the steps of: providing a base and preparing a first diaphragm on a first surface of the base; preparing a back plate on a surface of the first diaphragm opposite to the first surface; forming a first gap between the first diaphragm and the back plate; preparing a second diaphragm; forming a second gap between the second diaphragm and the back plate; preparing electrodes; forming a back cavity by etching the surface opposite to the first surface.