Elastic Wave Device Miniaturization via Through-Hole Positioning
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Solution Overview
Problem
Existing elastic wave devices using plate waves are limited by the large areas of piezoelectric thin films and sacrificial layers, which result in increased device size, hindering miniaturization.
Innovation Solution
The elastic wave device incorporates a support substrate with a recess covered by a piezoelectric substrate, featuring passing-through sections positioned within a minimum rectangular region encompassing the functional electrode, allowing for miniaturization without compromising excitation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a through-hole for etching is provided in the outer side portion of the functional electrode, then the hollow section can be formed, but the area of the piezoelectric thin film and sacrificial layer increases, making the device larger
Solution Approach 1:
The through-hole is repositioned from the traditional outer side portion to the inner region within the minimum rectangular region encompassing the functional electrode. This dimensional repositioning allows the hollow section to be formed without increasing the overall device footprint, as the etching access is now obtained within the existing functional area rather than adding to it from the outside.
Solution Approach 2:
The through-hole is strategically positioned in a specific location within the minimum rectangular region where it does not interfere with the functional electrode's operation. This localized positioning ensures that the etching function is achieved while maintaining the integrity and performance of the functional electrode, resolving the conflict between manufacturability and device size.
2Volume of moving object
If the area of piezoelectric thin film and sacrificial layer is reduced for miniaturization, then device size decreases, but excitation efficiency of elastic waves may be compromised
Solution Approach 1:
By moving the through-hole into the inner region of the minimum rectangular region, the design allows for reduced piezoelectric thin film area while maintaining excitation efficiency. The through-hole is positioned in a location that does not interfere with the functional electrode's ability to generate and propagate elastic waves effectively, thus enabling miniaturization without sacrificing performance.
Solution Approach 2:
The position of the through-hole is predetermined within the minimum rectangular region during the design phase, ensuring that it will not interfere with the functional electrode's operation. This preliminary positioning allows for optimized miniaturization while guaranteeing that excitation efficiency is maintained, as the through-hole location is carefully selected before manufacturing.
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 enables the miniaturization of elastic wave devices while maintaining high excitation efficiency, as the passing-through sections are strategically placed to avoid obstructing the functional electrode's function.
Implementation Method 1
an interdigital transducer (IDT) electrode that generates elastic waves
Data Source
AI summary
In an elastic wave device, a piezoelectric substrate is laminated on a support substrate including a recess. On one of a first principal surface and a second principal surface of the piezoelectric substrate, a functional electrode including an IDT electrode is provided. Passing-through sections are provided in the piezoelectric substrate and connected to a hollow section enclosed by the recess and the piezoelectric substrate. In a plan view of the piezoelectric substrate seen from the first principal surface, at least a portion of the passing-through sections is inside a minimum rectangular or substantially rectangular region encompassing an outer circumference of a region including the functional electrode.