Quartz Disk Resonator Gyroscope Coating for High Q Factor
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Solution Overview
Problem
Existing quartz-based disk resonator gyroscopes face challenges with Q factor degradation due to conductive coatings applied within deep trenches, leading to increased bias drift and energy loss, which affects the performance of MEMS devices.
Innovation Solution
A disk resonator gyroscope design featuring a quartz base with a quartz resonator disk and electrodes positioned outside the resonator, utilizing a bilayer Atomic Layer Deposition (ALD) coating comprising an ALD dielectric film and a noble metal layer to minimize energy loss and maintain high Q factors, while ensuring electrical connectivity and reduced micromasking defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive coating is applied within deep trenches of the resonator, then electrical connectivity is achieved, but the Q factor of the resonator is degraded
Solution Approach 1:
The patent extracts the conductive coating from the deep trenches of the resonator structure. Instead of coating the resonator with conductive material within the trenches, the invention positions electrodes externally and uses a different configuration that eliminates the need for conductive coatings inside the resonator trenches, thereby maintaining high Q factor while achieving electrical connectivity through alternative means
Solution Approach 2:
The patent introduces an intermediary approach by using a release wafer and handle wafer configuration with external electrodes. The electrical connectivity is achieved through an intermediary structure that connects to the resonator without requiring conductive coatings within the resonator trenches themselves, thus resolving the conflict between connectivity and Q factor
2Ease of manufacture
If a conductive coating is applied within deep trenches, then electrode functionality is enabled, but micromasking defects are created
Solution Approach 1:
The patent removes the conductive coating process from the deep trench fabrication sequence. By extracting this step and replacing it with external electrode configuration, the invention eliminates the micromasking defects that occur during trench coating while still achieving the necessary electrode functionality through the modified structure
Solution Approach 2:
Instead of coating the resonator trenches with conductive material from the inside, the patent inverts the approach by placing electrodes externally and achieving connectivity through the inverted configuration. This reversal of the conventional coating approach eliminates the micromasking problem inherent in deep trench coating processes
3Device complexity
If the resonator is coated with a conductive layer for internal electrodes, then electrode integration is simplified, but energy loss increases
Solution Approach 1:
The patent extracts the conductive layer coating from the resonator structure entirely. By removing this energy-loss-inducing coating and relocating electrode functionality to an external configuration, the invention simplifies the resonator structure itself while maintaining electrode integration through a different architectural approach that does not require internal conductive layers
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 solution significantly enhances the Q factor of the resonator, reducing bias drift and energy loss, thereby improving the performance and reliability of the gyroscope by maintaining high conductivity and conformality of the metal films, even in high-aspect-ratio structures.
Implementation Method 1
utilizing a bilayer Atomic Layer Deposition (ALD) coating comprising an ALD dielectric film and a noble metal layer
Data Source
AI summary
A method for producing a disk resonator gyroscope includes providing a base substrate and a handle wafer with a release hole, bonding a release wafer to the handle wafer, bonding a resonator wafer to the release wafer, etching the resonator wafer to form a disk resonator with a central pillar, and sense and drive electrodes, selectively applying a conductive film onto the disk resonator on a side of the disk resonator opposite the release wafer, on the outer edge of the disk resonator, and on the surfaces of the sense and drive electrodes facing the outer edge of the disk resonator, bonding the sense and drive electrodes and the central pillar of the disk resonator to the base substrate, and releasing the handle wafer by introducing a dry release agent into the release hole to undercut the release wafer.