Acoustic Wave Resonator Layout Using Shared Etch Lead Cavities
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing acoustic wave devices face limitations in the positioning of resonators due to etching holes, restricting their placement and affecting device size and performance.
Innovation Solution
The acoustic wave device incorporates a support substrate with space portions and a piezoelectric layer, allowing resonators to be positioned more freely, utilizing through-holes for etching and enabling the use of first thickness-shear mode bulk waves without reflectors, which enhances resonance characteristics and reduces propagation loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If etching holes are provided in the space portion to limit resonator positions, then manufacturing precision is improved, but device complexity and resonator placement flexibility worsen
Solution Approach 1:
The patent removes the etching holes from the space portion and extracts the positioning function to the support substrate surface, where protrusions are provided instead. This eliminates the need for complex etching processes while maintaining positioning precision.
Solution Approach 2:
Instead of using holes (negative space) for positioning, the patent uses protrusions (positive space) on the support substrate surface to define resonator positions, inverting the conventional approach.
2Manufacturing precision
If etching holes are provided in the space portion, then manufacturing precision is improved, but resonator placement flexibility worsens
Solution Approach 1:
The patent provides positioning protrusions only at specific locations on the support substrate surface where resonators need to be placed, rather than using a uniform etching hole pattern throughout the space portion. This allows flexible resonator placement while maintaining precision at critical positions.
3Reliability
If reflectors are used to achieve resonance, then resonance characteristics are improved, but device size increases
Solution Approach 1:
The patent removes the reflectors from the device structure and extracts the resonance function to the piezoelectric layer itself, which is excited to vibrate in thickness-shear mode. This eliminates the need for additional reflector components and reduces device size.
Solution Approach 2:
The patent replaces the mechanical reflector system with a piezoelectric vibration system, where the piezoelectric layer is directly excited to resonate in thickness-shear mode, achieving resonance without mechanical reflectors.
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 configuration allows for smaller device sizes with improved resonance characteristics, higher Q values, and reduced spurious emissions, while maintaining effective wave propagation and resonance.
Implementation Method 1
a piezoelectric layer provided on the support in the first direction... utilizing through-holes for etching and enabling the use of first thickness-shear mode bulk waves
Data Source
AI summary
An acoustic wave device includes a support including a support substrate with a thickness in a first direction, a piezoelectric layer on the support in the first direction on the support, and resonators each including a functional electrode on the piezoelectric layer in the first direction on the piezoelectric layer. The support includes space portions therein at positions where the functional electrodes at least partially overlap in a planar view in the first direction. The support includes a lead portion communicating with at least one of the space portions in a planar view in the first direction, at a position that does not overlap the space portion. At least one lead portion communicates with at least two of the space portions. The piezoelectric layer includes a through-hole penetrating the piezoelectric layer at a position overlapping the lead portion in a planar view in the first direction.