SAW Resonator Electrode Wrapping for TCF and Clutter Suppression
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Solution Overview
Problem
Existing surface acoustic wave (SAW) resonator devices face challenges in achieving optimal temperature coefficient of frequency (TCF) performance and effective clutter suppression due to misalignment of metal protrusions with the interdigital electrode ends during the manufacturing process.
Innovation Solution
The proposed solution involves a surface acoustic wave resonator device design where the interdigital electrode structure is embedded within a first temperature compensation layer, and a second temperature compensation layer is applied on top, ensuring tight wrapping of the electrode structure. Additionally, a protruding structure is formed in the interdigital electrode end regions to enhance clutter suppression, which is self-aligned with the electrode ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a lift-off process is used to form metal protrusions on interdigital electrode end regions, then the manufacturing process can be completed, but the metal protrusions cannot be completely vertically aligned with the edge of the interdigital electrode end, resulting in poor clutter suppression effect
Solution Approach 1:
The patent merges the metal protrusion formation with the interdigital electrode structure formation by using a single continuous metal layer that is patterned to form both the interdigital electrodes and the metal protrusions (hammer heads) in one lithography and metal deposition step, eliminating the need for a separate lift-off process and achieving perfect vertical alignment
Solution Approach 2:
The patent performs preliminary patterning of the metal layer to define both the interdigital electrode regions and the hammer head regions before metal deposition, ensuring that the hammer heads are pre-positioned to be vertically aligned with the interdigital electrode ends, avoiding alignment issues that would occur with post-formation alignment methods
2Reliability
If temperature compensation layers are applied to improve TCF performance, then the frequency stability over temperature is improved, but the manufacturing process and structural complexity increase
Solution Approach 1:
The patent changes the physical and chemical parameters of the temperature compensation layers by selecting specific materials (such as silicon oxide, silicon nitride, or diamond-like carbon) with appropriate thermal expansion coefficients and piezoelectric properties to counteract the temperature-induced frequency drift, achieving TCF performance improvement through material parameter optimization
Solution Approach 2:
The patent implements a nested layer structure where the first temperature compensation layer is embedded within or adjacent to the interdigital electrode structure, and the second temperature compensation layer is deposited on top, creating a compact multi-layer configuration that provides temperature compensation while maintaining a relatively compact device footprint
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 design improves the TCF performance of SAW resonator devices by ensuring better adhesion and alignment between the temperature compensation layers and the interdigital electrode structure, thereby enhancing the clutter suppression effect.
Implementation Method 1
a first temperature compensation layer, disposed on the base substrate; an interdigital electrode structure, disposed on the base substrate and at least partially embedded in the first temperature compensation layer... a second temperature compensation layer, located at a side of the first temperature compensation layer and the interdigital electrode structure away from the base substrate
Implementation Method 2
surface acoustic wave resonator device... interdigital electrode structure... a plurality of interdigital electrodes extending along a first direction and arranged along a second direction
Data Source
AI summary
A surface acoustic wave resonator device and method for manufacturing the same, and a surface acoustic wave filter, the surface acoustic wave resonator device includes: a first temperature compensation layer and an interdigital electrode structure, disposed on a base substrate, the interdigital electrode structure is at least partially embedded in the first temperature compensation layer, and includes interdigital electrodes extending along a first direction and arranged along a second direction; and a second temperature compensation layer, located on a side of the first temperature compensation layer and the interdigital electrode structure away from the base substrate; the interdigital electrode structure is surrounded and wrapped by the first temperature compensation layer in a direction parallel to the base substrate, and a surface of the interdigital electrode structure at a side away from the base substrate is covered by and in contact with the second temperature compensation layer.