BAW Filter Package with Buried Connections Under Resonators
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Solution Overview
Problem
The challenge in reducing the size of bulk acoustic wave (BAW) filter packages is exacerbated by their high frequency operation, making it difficult to miniaturize while maintaining performance and thermal dissipation.
Innovation Solution
Incorporating a buried connection metal layer underneath the resonator within the BAW device package, which reduces the overall size, enhances thermal dissipation, and minimizes parasitic capacitance by allowing input/output connections to be placed underneath the resonators, thus optimizing the package design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional BAW filter package structure is used, then the filter can operate at high frequencies, but the package size cannot be reduced
Solution Approach 1:
The patent moves the connection layer from the traditional planar surface to a buried position underneath the resonator in the vertical dimension. This dimensional repositioning allows I/O connections to be placed below the resonator footprint, enabling package size reduction while maintaining thermal dissipation pathways through the substrate.
Solution Approach 2:
The connection layer is nested within the package structure underneath the resonator, similar to nested dolls. This nesting approach allows the connection functionality to be embedded within the existing package volume without increasing the overall footprint, thereby reducing package size while maintaining all necessary functions.
2Volume of moving object
If connection layers are placed on the surface of the device substrate, then electrical connections are achieved, but the package size increases
Solution Approach 1:
The connection layer is repositioned from the horizontal surface plane to the vertical subsurface layer underneath the resonator. This dimensional change removes the connection layer from the resonator's electromagnetic field region, thereby minimizing parasitic capacitance while enabling more compact package layout.
Solution Approach 2:
The connection layer is extracted from its traditional position adjacent to or under the resonator electrodes and relocated to a buried position beneath the entire resonator structure. This extraction removes the connection layer from regions that would create parasitic capacitance, improving filter performance.
3Volume of moving object
If the package size is reduced, then integration is improved, but thermal dissipation capability deteriorates
Solution Approach 1:
The connection layer is repositioned to the vertical dimension underneath the resonator, creating a dedicated thermal conduction pathway through the substrate thickness direction. This vertical thermal path enables efficient heat dissipation from the resonator to the substrate and package exterior without requiring increased horizontal package area.
Data Source
AI summary
A method of manufacturing a packaged acoustic wave component includes forming or providing a device substrate, forming a metal layer over the device substrate, and forming or providing an acoustic wave device and mounting the acoustic wave device over at least a portion of the metal layer. The method also includes forming or providing a cap substrate, and forming or providing a peripheral wall, attaching one end of the peripheral wall to the device substrate so that the peripheral wall surrounds the acoustic wave device, and attaching the cap substrate to an opposite end of the peripheral wall. The method includes forming one or more vias so that the one or more vias extend through the device substrate and are disposed under the metal layer.