Acoustic Device Packaging With Dual Reflection Cavities
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Solution Overview
Problem
Existing film bulk acoustic resonator packaging limits performance improvement due to inadequate acoustic reflection structures and mechanical protection, leading to wave loss and environmental vulnerability.
Innovation Solution
A packaging structure and method featuring a substrate with a piezoelectric stack, a first organic material layer with supporting parts and windows, and a second organic material layer forming cavities and acoustic reflection structures to reduce wave loss and enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cavity is formed only in the effective area of the film bulk acoustic resonator with a single acoustic reflection structure, then the packaging structure is simple, but the acoustic wave reflection is insufficient leading to performance limitation
Solution Approach 1:
The packaging structure is divided into multiple functional regions: a first cavity in the effective area with a first acoustic reflection structure, and a second cavity in the bonding pad area with a second acoustic reflection structure. This segmentation allows each region to independently optimize acoustic wave reflection, solving the contradiction by improving overall reflection performance through divided functional zones rather than a single complex structure.
Solution Approach 2:
The invention extends the acoustic reflection function from a single-plane approach to a multi-dimensional configuration by creating separate first and second acoustic reflection structures in different spatial locations (effective area and bonding pad area respectively). This dimensional expansion enables comprehensive acoustic wave management across the entire resonator surface, improving reflection performance without requiring excessive complexity in any single location.
2Loss of energy
If the packaging structure includes multiple cavities and acoustic reflection structures, then acoustic wave loss is reduced and performance is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The first and second organic material layers are integrated into a unified packaging structure that simultaneously forms both the first cavity and second cavity. The acoustic reflection structures are combined with the cavity formation process, allowing multiple functions (protection, cavity formation, acoustic reflection) to be achieved through integrated manufacturing steps rather than separate complex processes.
Solution Approach 2:
The organic material layers serve multiple functions: they provide mechanical protection for the resonator, form the cavity structures through their layer configuration, and create the acoustic reflection structures at their interfaces. This multi-functionality reduces the need for separate components and manufacturing steps, improving ease of manufacture while maintaining the energy loss reduction benefits of multiple acoustic reflection structures.
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
The solution reduces acoustic wave loss by creating multiple reflection structures within the packaging, improving the performance of the acoustic device while providing mechanical protection and environmental resilience.
Implementation Method 1
the second supporting part forms a first acoustic reflection structure, and the first supporting part is matched with the second organic material layer to form a second acoustic reflection structure
Data Source
AI summary
The disclosure provides a packaging structure and method of an acoustic device, relating the technical field of semiconductors, including: a substrate and a piezoelectric stack structure located on the substrate, a first organic material layer is disposed on the piezoelectric stack structure, a second organic material layer is disposed on the first organic material layer, the first organic material layer includes a first supporting part and a second supporting part, the second supporting part forms a first acoustic reflection structure, when being transmitted to the first acoustic reflection structure, acoustic waves can be reflected back to the effective area, so that the loss of the acoustic waves is reduced, and the performance of the acoustic device is improved. The first supporting part is matched with the second organic material layer to form a second acoustic reflection structure, so that when part of acoustic waves are not reflected back by the first acoustic reflection structure and are transmitted to the second acoustic reflection structure, the acoustic waves can be reflected back to the effective area, so that the loss of the acoustic waves is further reduced, and the performance of the acoustic device is improved.