Sensor Membrane Insulating Layer Prevents Overetching
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Solution Overview
Problem
Current pressure sensors face challenges in miniaturization and improving yield and quality, particularly in detecting pressure changes effectively in small sizes using microelectromechanical systems (MEMS) techniques.
Innovation Solution
A sensor membrane structure is developed with a substrate, a first insulating layer, and a device layer, where a cavity on the substrate's surface communicates with an opening on the opposite surface, allowing pressure changes to be detected by an electronic component disposed within the cavity, and the insulating layer is etched to enhance sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of pressure sensors is reduced using MEMS techniques, then miniaturization is achieved, but yield and quality deteriorate
Solution Approach 1:
The sensor structure is divided into distinct functional layers including substrate, insulating layer, device layer, and cavity structure. This segmentation allows each layer to be optimized independently for its specific function while maintaining overall sensor performance in miniaturized form factors
Solution Approach 2:
The insulating layer is formed on the substrate before bonding the device layer, preparing the structure in advance for subsequent etching processes. This preliminary action ensures proper adhesion and prevents overetching, thereby improving yield and quality in miniaturized sensors
2Measurement precision
If the insulating layer is etched to enhance sensitivity, then detection precision is improved, but overetching may occur causing structural damage
Solution Approach 1:
The insulating layer is formed as a protective barrier before the etching process. This preliminary protective action allows controlled etching of the substrate to enhance sensitivity while preventing overetching that would damage underlying structures
Solution Approach 2:
The insulating layer acts as an intermediary protective layer between the etching process and the device layer. It enables precise etching for enhanced pressure detection sensitivity while protecting the device layer from damage, thus maintaining structural integrity
3Measurement precision
If the cavity and opening penetrate the substrate, then pressure detection capability is improved, but manufacturing complexity increases
Solution Approach 1:
The pressure detection structure is segmented into cavity formation, opening formation, and layer bonding as separate sequential steps. This segmentation makes the complex penetration process more controllable and manufacturable while maintaining pressure detection capability
Solution Approach 2:
The insulating layer is formed on the substrate before creating the cavity and opening structures. This preliminary action simplifies subsequent manufacturing steps by providing a protective barrier that prevents overetching, thereby reducing overall manufacturing complexity
Data Source
AI summary
A sensor membrane structure is provided. The sensor membrane structure includes a substrate, a first insulating layer, and a device layer. The substrate has a first surface and a second surface that is opposite to the first surface. A cavity is formed on the first surface, an opening is formed on the second surface, and the cavity communicates with the opening. The cavity and the opening penetrate the substrate in a direction that is perpendicular to the first surface. The first insulating layer is disposed on the first surface of the substrate. The device layer is disposed on the first insulating layer. The first insulating layer is disposed for protecting the sensor membrane structure from overetched and remain stable during the etching process, increasing the yield of the sensor membrane structure.