Stacked BAW-SAW Filter Packaging for Smaller RF Footprints
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Solution Overview
Problem
Current acoustic wave filters face challenges in reducing size while maintaining performance and cost-effectiveness, particularly in radio frequency electronic systems, where achieving desirable filter performance in smaller modules is difficult.
Innovation Solution
The solution involves a stacked arrangement of bulk acoustic wave (BAW) resonators and surface acoustic wave (SAW) devices, with interconnections through internal and external conductive vias, allowing for a hybrid acoustic wave filter component that reduces overall size by eliminating the need for separate dies for BAW and SAW devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If separate dies are used for BAW and SAW devices, then manufacturing simplicity is maintained, but the overall size and footprint of the filter component increases
Solution Approach 1:
The patent combines BAW resonators and SAW devices into a single integrated filter component structure, eliminating the need for separate dies. The BAW resonators are positioned in a stacked arrangement with SAW devices, sharing common support structures and interconnection layers, which reduces the overall footprint while integrating multiple functions into one compact unit.
Solution Approach 2:
The patent transitions from a planar arrangement of separate dies to a three-dimensional stacked configuration. BAW resonators are positioned above and below SAW devices, utilizing vertical stacking to reduce horizontal footprint. Internal and external conductive vias provide interconnections across multiple layers, enabling complex functionality in a compact vertical architecture.
2Ease of manufacture
If BAW and SAW devices are integrated in a stacked arrangement, then footprint is reduced, but manufacturing complexity increases due to internal and external conductive vias
Solution Approach 1:
The patent divides the interconnection structure into two distinct segments: internal conductive vias formed within the stacked device layers, and external conductive vias providing access from external connections. This segmentation allows each via type to be optimized and manufactured separately, with the internal vias integrated during the stacking process and external vias added subsequently for electrical access.
Solution Approach 2:
The patent performs preliminary formation of internal conductive vias during the stacking process, establishing the interconnection architecture before final assembly. This preliminary action enables subsequent external via formation and electrical connection without requiring complex post-assembly alignment, as the internal via positions are predetermined by the stacking sequence and layer registration.
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 approach enables a smaller footprint for acoustic wave filter components, providing improved design freedom and performance while maintaining cost-effectiveness by integrating BAW and SAW devices in a single, compact structure.
Implementation Method 1
a surface acoustic wave device that includes a first piezoelectric layer, an interdigital transducer electrode on the first piezoelectric layer
Implementation Method 2
The bulk acoustic wave resonator includes a second piezoelectric layer and electrodes on opposing sides of the second piezoelectric layer
Implementation Method 3
The surface acoustic wave resonator can generate a surface acoustic wave on a surface of the piezoelectric layer on which the interdigital transductor electrode is disposed
Data Source
AI summary
A packaged acoustic wave filter component can include an acoustic wave device including a first piezoelectric layer and an interdigital transducer electrode on the first piezoelectric layer. A support layer may be included over the acoustic wave device, and the packaged hybrid filter component can also include a bulk acoustic wave resonator over the support layer. A cap layer may extend over and encapsulate the bulk acoustic wave resonator. One or more external vias may extend through the support layer and the underlying layers of the acoustic wave device to provide electrical communication with the packaged bulk acoustic wave generator.