MEMS Pressure Sensor Reference Capacitance Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MEMS pressure sensors face challenges in achieving high detection accuracy due to variations in manufacturing processes and temperature dependencies, which affect the reliability of pressure measurements.
Innovation Solution
The design incorporates a pressure sensing MEMS element with a diaphragm and movable electrode configuration that includes a through hole, allowing for a reference capacitance MEMS element to correct temperature dependencies and reduce manufacturing variations, resulting in enhanced sensing accuracy by maintaining a consistent distance between electrodes under pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional MEMS pressure sensor structure is used, then the device is simple to manufacture, but the detection accuracy is limited due to temperature dependencies and manufacturing variations
Solution Approach 1:
The device is divided into two separate MEMS elements: a pressure sensing element and a reference capacitance element. This segmentation allows each element to perform its specific function independently, with the reference element specifically designed to compensate for temperature and manufacturing variations, thereby improving overall detection accuracy without requiring complex integration within a single element
Solution Approach 2:
The reference capacitance element acts as an intermediary that measures environmental variations (temperature and manufacturing differences) and provides compensation data. This intermediary element enables the system to correct for external factors affecting the pressure sensing element, improving measurement precision without directly modifying the pressure sensing mechanism itself
2Measurement precision
If the diaphragm sags under pressure, then pressure detection is enabled, but the distance between electrodes varies causing capacitance variation that reduces measurement reliability
Solution Approach 1:
The invention changes the operational parameter from measuring absolute capacitance values to measuring differential capacitance changes between two elements. By using the reference element to establish a baseline and comparing deviations from this baseline, the system can accurately measure pressure-induced capacitance changes while compensating for variations in absolute electrode distances caused by diaphragm sagging and manufacturing tolerances
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 configuration enhances the detection accuracy of MEMS pressure sensors by providing a greater change in capacitance for the same pressure magnitude and reduces the influence of temperature and manufacturing variations, leading to improved measurement reliability.
Implementation Method 1
the distance between the fixed and movable electrodes varies, thereby varying the electrostatic capacitance therebetween. The MEMS pressure sensor employs a principle that pressure is detected utilizing the relationship between pressure and electrostatic capacitance.
Data Source
AI summary
According to one embodiment, a MEMS device is disclosed. The device includes a substrate, a first and second MEMS elements on the substrate. Each of the first and second MEMS elements includes a fixed electrode on the substrate, a movable electrode above the fixed electrode, a first insulating film, the first insulating film and the substrate defining a cavity in which the fixed and movable electrodes are contained, and a first anchor on a surface of the first insulating film inside the cavity and configured to connect the movable electrode to the first insulating film. The cavity of the first MEMS element is closed. The cavity of the second MEMS element is opened by a through hole.