MEMS Microphone Annular Supporter and Insulating Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MEMS microphones face issues with the peeling off of the lower diaphragm electrode due to prolonged releasing time and exposure of the upper electrode to strong releasing solutions during the manufacturing process, which can cause damage.
Innovation Solution
A MEMS microphone structure is designed with an annular supporter that extends to the lower diaphragm electrode and substrate, and an insulating layer that encloses the upper electrode, preventing the peeling off of the lower diaphragm electrode and protecting the upper electrode during the releasing process by stopping the air gap formation within the annular supporter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the releasing time is extended to completely remove the sacrificial layer, then the air gap formation is improved, but the lower diaphragm electrode peels off
Solution Approach 1:
The annular supporter structure is formed in advance before the releasing process, creating a physical barrier that prevents the releasing solution from reaching the diaphragm electrode. This preliminary structural preparation allows the releasing process to be performed without risking electrode peeling, as the supporter is already in place to protect the critical interface between the diaphragm and substrate.
Solution Approach 2:
The annular supporter acts as an intermediary structure between the sacrificial layer and the diaphragm electrode. It provides a protective barrier that mediates the releasing process, allowing the sacrificial layer to be removed while preventing the releasing solution from directly contacting and damaging the diaphragm electrode interface.
2Manufacturing precision
If acoustic holes are formed in the back plate, then the air gap communication is improved, but the upper electrode is exposed to releasing solution
Solution Approach 1:
The insulating layer is deposited over the upper electrode before forming the acoustic holes, creating a protective barrier in advance. This preliminary protection ensures that when acoustic holes are later formed to enable air gap communication, the upper electrode is already shielded from the releasing solution that will be used in subsequent processing steps.
Solution Approach 2:
The insulating layer serves as an intermediary protective barrier between the upper electrode and the releasing solution. It allows the acoustic holes to be formed for proper air gap communication while simultaneously protecting the upper electrode from damage by the releasing solution during the manufacturing process.
Data Source
AI summary
A MEMS microphone structure, comprising a semiconductor substrate having a cavity, a first dielectric layer having a through-hole communicating with the cavity, a lower diaphragm electrode formed above the through-hole and at least partially attached to the upper surface of the first dielectric layer, and an upper electrode structure with an insulating layer. The upper electrode structure comprises an annular supporter, a back plate having multiple holes, and an upper electrode connection. At least a part of the annular supporter extends downwardly to the lower diaphragm electrode while the rest of the annular supporter extends downwardly to the substrate. The back plate is suspended above the lower diaphragm electrode by the annular supporter, forming an air gap therebetween. An upper electrode is embedded in the insulating layer at the back plate and is lead out by the upper electrode connection.