Solidly Mounted Resonator With Integrated EMI Shielding Wall
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Solution Overview
Problem
Conventional solidly mounted resonators lack electromagnetic shielding, leading to reduced performance and quality factors due to poor C-axis preferred orientation of electrode layers, which increases the risk of electromagnetic interference and requires additional shielding devices, thereby increasing dimension and reducing performance.
Innovation Solution
A solidly mounted resonator with an integrated electromagnetic shielding structure, featuring a metal shielding wall surrounding the acoustic-wave reflecting and resonance function layers, formed during fabrication using multiple metal rings and dielectric reflection layers stacked in an interleaved manner, providing effective shielding against external and internal electromagnetic interferences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SMR devices are used without electromagnetic shielding, then the device structure remains simple, but electromagnetic interference from external and internal sources degrades performance and quality factor
Solution Approach 1:
The patent merges the electromagnetic shielding function with the resonator structure by forming the shielding wall from the same piezoelectric material and using the same fabrication processes. The shielding wall is integrated into the resonator body, eliminating the need for separate shielding components while providing effective electromagnetic interference protection.
Solution Approach 2:
The piezoelectric material serves multiple functions: it provides the resonator's acoustic wave functionality and simultaneously acts as an electromagnetic shielding material. The same material and structure that enables resonance also blocks electromagnetic interference, achieving multi-functionality without adding separate components.
2Object-affected harmful factors
If additional electromagnetic shielding devices are added to conventional SMR, then shielding against electromagnetic interference is improved, but device dimension increases and performance decreases
Solution Approach 1:
The shielding function is merged into the resonator structure itself. The shielding wall is formed as an integral part of the resonator using the same piezoelectric material and fabrication steps, eliminating the need for additional external shielding devices and maintaining compact dimensions.
Solution Approach 2:
The electromagnetic shielding wall is nested within the resonator structure, with the shielding function embedded inside the same physical boundaries as the resonator elements. This nested approach provides shielding without increasing the overall device footprint.
3Reliability
If conventional fabrication processes are used for SMR, then the manufacturing process remains simple, but the C-axis preferred orientation of electrode and piezoelectric layers is poor, reducing performance
Solution Approach 1:
The patent applies preliminary actions during fabrication by forming the shielding wall simultaneously with the resonator layers through pre-planned photolithography and etching steps. The shielding structure is prepared in advance as part of the layer formation process, ensuring proper C-axis orientation without requiring post-fabrication adjustments.
Solution Approach 2:
The fabrication process parameters are changed to include specific photolithography and etching conditions that promote C-axis preferred orientation. By adjusting these parameters during the formation of the shielding wall and resonator layers, the patent achieves better crystal orientation while maintaining manufacturing feasibility.
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 integrated shielding structure enhances signal isolation, suppresses noise signals, especially for adjacent frequency bands and signal transmitters, while maintaining a small dimension and high performance, and improves heat dissipation and product yield by ensuring a flat surface for the piezoelectric layer, thus addressing the issues of electromagnetic interference and performance reduction.
Implementation Method 1
The resonance function layer includes a lower electrode layer, a piezoelectric layer, and an upper electrode layer, which are stacked in the above-listed sequence. The resonance function layer is configured to implement conversion between electrical energy and mechanical energy via the piezoelectric layer, and the mechanical energy is in a form of acoustic waves.
Implementation Method 2
The acoustic-wave reflecting layer is characterized by having alternating high and low acoustic impedance, and thus is capable to reflect the acoustic waves effectively.
Data Source
AI summary
A solidly mounted resonator having an electromagnetic shielding structure and a method for manufacturing the same. The solidly mounted resonator includes: a substrate; an acoustic-wave reflecting layer formed on the substrate; a resonance function layer formed on the acoustic-wave reflecting layer; and a metal shielding wall formed on the substrate, wherein the metal shielding wall surrounds an effective region in the acoustic-wave reflecting layer and the resonance function layer. The electromagnetic shielding structure is formed simultaneously with the resonator, and it is not necessary to provide an additional electromagnetic shielding device. An influence of an external or internal electromagnetic interference source on the resonator is avoided while ensuring a small dimension and a high performance of the resonator.