Lamb Wave Resonator Layout for Multi-Frequency Fabrication

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Solution Overview

Problem

Conventional Lamb wave resonators require redesigning and re-fabricating reticles with different branch layouts to filter electrical signals across various frequency ranges, which is inefficient.

Innovation Solution

A Lamb wave resonator design featuring a piezoelectric material layer with interdigitated finger electrodes and floating electrodes, where specific branches are cut off to adjust the resonance frequency, allowing for a single reticle layout to produce resonators with different frequency ranges by modifying the branch pitches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the resonance frequency of the resonator is adjusted by changing the pitches between branches, then the resonance frequency can be modulated to filter different frequency ranges, but it requires redesigning the layout and re-fabricating reticles for each frequency range

Engineering Contradiction:

Improvefrequency range adaptabilityVSAvoidreticle design complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The resonator structure is divided into a fixed electrode layout and variable pitch regions. The finger electrodes are segmented into multiple branches with adjustable pitches, allowing frequency modulation without changing the overall electrode configuration. This enables different frequency ranges to be achieved by modifying only the pitch parameters of specific branches rather than redesigning the entire reticle.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the pitch parameter between finger electrode branches to modulate the resonance frequency. By adjusting the pitch distance between adjacent branches, the resonator can be tuned to different frequency ranges while maintaining the same physical electrode layout, thus avoiding the need to re-fabricate reticles for each frequency application.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the resonance frequency is adjusted by changing the pitches between branches, then the resonance frequency can be modulated, but the fabrication process becomes more complex requiring multiple reticles

Engineering Contradiction:

Improvefrequency modulation capabilityVSAvoidfabrication process simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

A single reticle design with variable pitch branches serves multiple frequency filtering functions. The same electrode layout can be used to fabricate resonators for different frequency ranges by simply adjusting the pitch parameters during fabrication, making the manufacturing process universal across different frequency applications rather than requiring separate specialized reticles for each frequency band.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If a single reticle layout is used with modified branch pitches, then the fabrication process is simplified, but the resonance frequency needs to be lowered

Engineering Contradiction:

Improvefabrication process simplicityVSAvoidresonance frequency control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The pitch between branches is designed as a variable parameter rather than a fixed dimension. This dynamic approach allows the pitch to be adjusted according to the desired resonance frequency, enabling precise frequency control while using the same reticle layout. The variable pitch design transforms a static fabrication process into a tunable one, maintaining manufacturing simplicity while achieving frequency precision.

Inventive Principle:

Principle #15Dynamics

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

Enables the production of Lamb wave resonators with lower resonance frequencies without redesigning the electrode layout, simplifying the fabrication process and reducing the need for multiple reticles.

Implementation Method 1

a piezoelectric material layer, a first finger electrode disposed on one side of the piezoelectric material layer, and a second finger electrode disposed on the other side of the piezoelectric material layer

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the resonance frequency of the resonator could be modulated, so that electrical signals with specific frequencies would pass through the resonator

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS11784627B2Lamb wave resonator and method of fabricating the same

Publication Date: 2023.10.10 VANGUARD INTERNATIONAL SEMICONDUCTOR CORPORATION

AI summary

A Lamb wave resonator includes a piezoelectric material layer, a first finger electrode, a second finger electrode, at least two floating electrodes, and at least two gaps. The first finger electrode is disposed on one side of the piezoelectric material layer and includes a first main portion and first fingers. The second finger electrode is disposed on the side of the piezoelectric material layer and includes a second main portion and second fingers. The first fingers are parallel to and alternately arranged with the second fingers. The floating electrodes are disposed between each first finger and each second finger, and the gaps are disposed at two ends of each floating electrode, respectively.