Quartz MEMS Resonator Electrode Topology for Chip Integration
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Solution Overview
Problem
Conventional kHz frequency quartz tuning fork resonators are difficult to integrate with other components due to the need for side electrodes, which complicates wafer-level processing and results in low yield and large resonator sizes, limiting their integration with MHz oscillators for compact RF systems.
Innovation Solution
A method for fabricating piezoelectric quartz tuning fork resonators with electrodes only on top and bottom surfaces, eliminating the need for side electrodes, allowing for wafer-scale processing and integration with MHz shear-mode resonators on a common semiconductor substrate, enabling smaller resonator sizes and improved integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional kHz frequency quartz tuning fork resonators are fabricated with side electrodes, then the resonators can operate at kHz frequencies, but the device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent removes the side electrodes from the resonator structure, extracting only the necessary top and bottom electrodes. This simplifies the device geometry and eliminates the manufacturing complexity associated with depositing electrodes on vertical sidewalls, while maintaining the kHz operating frequency through optimized top/bottom electrode configurations.
Solution Approach 2:
The patent transitions from a three-dimensional electrode deposition process (requiring side electrodes on vertical surfaces) to a two-dimensional planar electrode arrangement (only top and bottom surfaces). This dimensional simplification enables standard wafer-level processing techniques to be used, dramatically improving manufacturability and yield.
2Measurement precision
If conventional kHz resonators are fabricated with side electrodes, then the resonator function is achieved, but the resonator size becomes large
Solution Approach 1:
By removing the side electrodes and their associated structural requirements, the resonator footprint is significantly reduced. The simplified geometry allows for compact designs that fit within smaller areas on the substrate, enabling better integration with other components.
3Measurement precision
If conventional kHz resonators are fabricated with side electrodes, then the resonator operates at kHz frequency, but the integration with other components becomes difficult
Solution Approach 1:
The simplified resonator structure with only top and bottom electrodes can be fabricated using the same wafer-level processing techniques as MHz shear-mode resonators. This universal fabrication approach allows both kHz and MHz oscillators to be integrated on a common semiconductor substrate, enabling compact RF systems with optimized power budgets.
4Productivity
If conventional kHz resonators are fabricated using wafer-level processing, then productivity is improved, but manufacturing precision deteriorates due to side electrode deposition challenges
Solution Approach 1:
By eliminating the side electrode deposition step, the patent removes the primary source of manufacturing precision problems. Standard planar deposition techniques can be used for the top and bottom electrodes, achieving high precision and uniformity while maintaining high productivity through wafer-level batch processing.
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 approach enables the fabrication of ultra-small kHz resonators with high Q factors, reducing phase noise and power consumption, and allows for the integration of kHz and MHz oscillators on a single chip, optimizing power budgets in RF systems.
Implementation Method 1
piezoelectric quartz tuning fork resonator having a pair of tines formed from a common quartz plate
Implementation Method 2
the tines vibrate in response thereto in a tuning fork mode
Data Source
AI summary
A piezoelectric quartz tuning fork resonator having a pair of tines formed from a common quartz plate, with a middle electrode and two outer electrodes being disposed at or on top and bottom surfaces of each of the pair of tines and interconnected such that the outer electrodes at or on the top and bottom surfaces of a first one of the pair of tines are connected in common with the middle electrodes on the top and bottom surfaces of a second one of the pair of tines and further interconnected such that the outer electrodes at or on the top and bottom surfaces of the second one of the pair of tines are connected in common with the middle electrodes on the top and bottom surfaces of the first one of the pair of tines.