MEMS Acceleration and Pressure Sensor Integration
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Solution Overview
Problem
Current MEMS devices with integrated multiple sensors have complex fabrication processes and large volumes due to separate fabrication and packaging of acceleration and pressure sensors, leading to high manufacturing costs.
Innovation Solution
A vertical integration approach is used to form acceleration and pressure sensors on a substrate with integrated circuits, where the pressure sensor is formed above the acceleration sensor, reducing interference and overall device volume, and both are electrically connected to the substrate's integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acceleration sensors and pressure sensors are fabricated separately and then packaged together, then each sensor can be optimized independently, but the device volume increases and manufacturing cost rises
Solution Approach 1:
The patent combines acceleration sensors and pressure sensors into a single integrated device fabricated on one substrate. The acceleration sensor includes movable electrodes and fixed electrodes forming a capacitive structure, while the pressure sensor uses a diaphragm structure with electrodes, both integrated on the same substrate sharing common support structures and fabrication processes, thereby reducing overall device volume while maintaining manufacturing quality
Solution Approach 2:
The substrate serves multiple functions: it provides mechanical support for both acceleration and pressure sensing elements, acts as a common base for electrical connections, and enables shared fabrication processes. The support structures and electrical interconnections are designed to serve both sensor types simultaneously, reducing the need for separate components and packaging
2Manufacturing precision
If acceleration sensors and pressure sensors are fabricated separately and then packaged together, then each sensor can be optimized independently, but manufacturing complexity increases and cost rises
Solution Approach 1:
The patent merges the fabrication processes for acceleration and pressure sensors into a single integrated manufacturing sequence. Both sensor types are formed on the same substrate using coordinated deposition, etching, and release processes, eliminating the need for separate fabrication and packaging operations, thereby reducing manufacturing complexity while maintaining quality
Solution Approach 2:
The integrated device is segmented into distinct functional regions: acceleration sensor areas with movable and fixed electrodes, pressure sensor areas with diaphragm structures, and shared support structures. This segmentation allows independent optimization of each sensor type within the unified fabrication process, maintaining manufacturing precision while simplifying overall process integration
3Volume of stationary object
If acceleration sensors and pressure sensors are integrated on a single substrate, then device volume is reduced and fabrication is simplified, but electrical connection complexity increases
Solution Approach 1:
The patent combines electrical connection structures for both acceleration and pressure sensors into integrated interconnection layers formed on the substrate. Conductive traces and contact structures are deposited and patterned to provide electrical pathways to both sensor types through shared routing layers, reducing the number of separate connection structures needed while maintaining reliable electrical connectivity
Data Source
AI summary
The present disclosure provides MEMS devices and their fabrication methods. A first dielectric layer is formed on a substrate including integrated circuits therein. One or more first metal connections and second metal connections are formed in the first dielectric layer and are electrically connected to the integrated circuits. A second dielectric layer is formed on the first dielectric layer. An acceleration sensor is formed in the second dielectric layer to electrically connect to the one or more first metal connections. One or more first metal vias are formed in the second dielectric layer to electrically connect to the second metal connections. A pressure sensor is formed on the second dielectric layer to electrically connect to the first metal vias. The MEMS devices provided by the present disclosure are compact in size through the integration of the acceleration sensor and the pressure sensor.