MEMS Capacitive Gyro Sensor Comb Electrode Protection
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Solution Overview
Problem
Current MEMS sensors face challenges in achieving high detection sensitivity and accuracy due to electrode short-circuiting and complex manufacturing processes, particularly in forming protective layers and reducing electrode size variations.
Innovation Solution
A capacitance type MEMS sensor design featuring comb-tooth-like electrodes with insulating layers and a simplified manufacturing method using a semiconductor substrate with a cavity, where the electrodes are formed by processing the substrate to engage at intervals, and a protective layer is created without bonding materials, reducing costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is formed by bonding methods, then electrode protection is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the protective layer formation from complex bonding processes and implements it through simple chemical vapor deposition (CVD), removing unnecessary manufacturing complexity while maintaining electrode protection functionality
Solution Approach 2:
The patent replaces mechanical bonding methods with chemical vapor deposition, substituting a complex mechanical assembly process with a simpler chemical process that forms the protective layer in-situ
2Volume of moving object
If electrode size is reduced for downsizing, then device miniaturization is achieved, but detection sensitivity decreases
Solution Approach 1:
The patent applies local quality enhancement by creating comb-tooth electrode structures with optimized local geometry, where the interdigitated teeth provide enhanced capacitance coupling and detection sensitivity despite the overall device being downsized
Solution Approach 2:
The patent uses composite material structures with multiple dielectric layers having different permittivity values to enhance the capacitance effect, allowing smaller electrode areas to achieve the same detection sensitivity as larger electrodes
3Measurement precision
If comb-tooth electrodes are used, then detection sensitivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements self-service by using CVD processes that automatically conform to the electrode structure, where the protective layer forms uniformly on the comb-tooth geometry without requiring additional alignment or precision control steps
4Ease of manufacture
If simple manufacturing method is used, then production cost is reduced, but electrode protection reliability may be compromised
Solution Approach 1:
The patent replaces complex mechanical bonding procedures with simple chemical vapor deposition, achieving both manufacturing simplicity and reliable electrode protection through a single in-situ CVD process step
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
The design enhances detection sensitivity and accuracy by preventing electrode short-circuits and simplifying the manufacturing process, allowing for precise control of electrode dimensions and improved reliability of the MEMS package.
Implementation Method 1
forming an insulating layer between the fixed electrode and the movable electrode
Implementation Method 2
a capacitance type that performs detection based on a change in capacitance of a capacitor
Data Source
AI summary
A capacitance type gyro sensor includes a semiconductor substrate, a first electrode integrally including a first base portion and first comb tooth portions and a second electrode integrally including a second base portion and second comb tooth portions, formed by processing the surface portion of the semiconductor substrate. The first electrode has first drive portions that extend from opposed portions opposed to the respective second comb tooth portions on the first base portion toward the respective second comb tooth portions. The second electrode has second drive portions formed on the tip end portions of the respective second comb tooth portions opposed to the respective first drive portions. The first drive portions and the second drive portions engage with each other at an interval like comb teeth.