Patterned Mass Loading in BAW Resonators for Multi-Frequency Tuning
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Solution Overview
Problem
Manufacturing bulk acoustic wave resonators with different resonant frequencies involves a high number of processing steps, increasing complexity and cost.
Innovation Solution
The use of patterned mass loading layers with different densities, formed during a common processing step, to achieve varying resonant frequencies in bulk acoustic wave resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple separate processing steps are used to manufacture BAW resonators with different resonant frequencies, then each resonator can be precisely tuned to its specific frequency, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent combines multiple separate processing steps into a single integrated process. Specifically, it merges the mass loading layer formation and resonant frequency tuning steps into one common processing step, where a single mass loading layer with a specific pattern is formed to simultaneously tune multiple BAW resonators to different resonant frequencies. This reduces the number of processing steps while maintaining frequency precision.
Solution Approach 2:
The patent creates a universal processing step that serves multiple functions. The common processing step forms mass loading layers for multiple different BAW resonators simultaneously, and the single patterned mass loading layer performs the dual function of providing mechanical support and tuning the resonant frequency. This multi-functional approach eliminates the need for separate tuning steps for each resonator.
2Manufacturing precision
If multiple separate processing steps are used to manufacture BAW resonators with different resonant frequencies, then each resonator can be precisely tuned, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple costly separate processing steps into one common processing step. By forming all mass loading layers in a single step rather than performing separate deposition and tuning steps for each resonator, the manufacturing cost is reduced while maintaining the ability to precisely control resonant frequencies through the pattern design.
3Device complexity
If different density mass loading layers are formed in a common processing step, then processing complexity is reduced, but maintaining different densities in the same step becomes challenging
Solution Approach 1:
The patent applies local quality by creating a patterned mass loading layer where different regions have different effective densities. The pattern consists of openings and filled regions that create local variations in mass distribution. This local differentiation achieves different resonant frequency tuning for multiple resonators while using a single uniform material layer deposited in one processing step.
Solution Approach 2:
The patent changes the geometric parameters of the mass loading layer pattern rather than changing the material density. By varying the pattern geometry (opening size, shape, and distribution), the effective mass loading is adjusted locally to achieve different resonant frequencies. This parameter change approach maintains manufacturing simplicity while achieving precise frequency control.
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
Reduces processing complexity and cost by allowing multiple resonant frequencies to be tuned using a single parameter in a common processing step, while maintaining accurate frequency control.
Implementation Method 1
The first patterned mass loading layer impacts a resonant frequency of the first bulk acoustic wave resonator. The second patterned mass loading layer impacts a resonant frequency of the second bulk acoustic wave resonator.
Implementation Method 2
In BAW resonators, acoustic waves propagate in a bulk of a piezoelectric layer.
Data Source
AI summary
Methods of manufacturing bulk acoustic wave resonators are disclosed. During a common processing step, a first patterned mass loading layer for a first bulk acoustic wave resonator is formed and a second patterned mass loading layer for a second bulk acoustic wave resonator is formed. The first patterned mass loading layer has a different density than the second patterned mass loading layer.