Micromechanical Sensor Device With Shared Trench Process
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current micromechanical sensor devices face challenges in compactly integrating combined pressure and inertial sensors with efficient production methods, particularly in achieving equal reference pressures and simplified electrical connections.
Innovation Solution
The proposed solution involves a shared trench process for creating through openings and backthinining the diaphragm region, forming connection channels for equal reference pressures, and using a cap device with exposed bond lead regions for electrical connections, along with additional micromechanical function layers to enhance sensitivity and space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate production processes are used for pressure and inertial sensors, then each sensor can be optimized independently, but the device complexity and production time increase
Solution Approach 1:
The patent combines the production of pressure sensors and inertial sensors into a single integrated device with a unified structure. The micromechanical function layers are formed in a single substrate, sharing common elements such as the diaphragm region, reference pressure cavities, and electrode configurations. This merging eliminates the need for separate production processes while maintaining optimization capabilities for both sensor types through coordinated design of the shared structures.
Solution Approach 2:
The micromechanical function layers are designed to serve multiple functions simultaneously. The same substrate and micromechanical structures provide both pressure sensing capabilities (through the diaphragm region) and inertial sensing capabilities (through the movable electrode regions). The reference pressure cavities serve both pressure stabilization and as structural elements for the inertial sensor operation, reducing overall device complexity while maintaining specialized optimization for each sensing function.
2Reliability
If reference pressure cavities are isolated, then reference pressure stability is improved, but the production process becomes more complex
Solution Approach 1:
The patent establishes fluidic connection channels that communicate between the first and second reference pressure cavities, allowing the reference pressures to be equalized and maintained at a common value. This merging of the previously isolated cavities simplifies the production process by eliminating the need for separate reference pressure establishment procedures while maintaining stability through the interconnected design that prevents pressure drift.
3Ease of manufacture
If bond lead regions are exposed through cap device, then electrical connection is simplified, but the cap device complexity increases
Solution Approach 1:
The patent extracts the bond lead regions from the bulk of the micromechanical function layers by forming through openings in the cap device that expose specific bond lead regions at defined locations. This extraction allows direct electrical access to the sensor elements without requiring complex internal routing within the cap device. The cap device maintains a relatively simple structure with through openings that provide straightforward electrical connection paths while keeping the bond lead regions accessible for wire bonding or other electrical attachment methods.
4Measurement precision
If multiple micromechanical function layers are used, then sensor sensitivity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent divides the sensor structure into multiple micromechanical function layers formed at different stages of the production process. Each layer serves a specific function (e.g., first layer for inertial sensor structures, second layer for pressure sensor diaphragm, third layer for additional sensing elements). This segmentation allows each layer to be optimized and formed with appropriate precision requirements, reducing the overall manufacturing difficulty compared to forming a single complex multi-functional layer. The layered approach enables incremental building of sensitivity while maintaining manageable precision requirements for each individual layer formation step.
Data Source
AI summary
A micromechanical sensor device and a corresponding production method. The micromechanical sensor device has a substrate which has a front side and a rear side. Formed on the front side, at a lateral distance, are an inertial sensor region having an inertial structure for acquiring external accelerations and/or rotations, and a pressure sensor region having a diaphragm region for acquiring an external pressure. A micromechanical function layer by which the diaphragm region is formed in the pressure sensor region. A micromechanical function layer is applied on the micromechanical function layer, the inertial structure being formed out of the second and third micromechanical function layer. A cap device encloses a first predefined reference pressure in a first cavity in the inertial sensor region, and a second cavity is formed underneath the diaphragm region.