Polymer Cap Acoustic Package Structure for Smaller Footprint
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Solution Overview
Problem
There is a need for packages with acoustic devices that have better form factors and smaller sizes, as devices have become increasingly compact.
Innovation Solution
A package comprising an acoustic device, a polymer frame coupled to the acoustic device, a plurality of frame interconnects, a polymer cap layer configured as a cap for the acoustic device, a plurality of cap interconnects, and a cavity between the acoustic device and the polymer cap layer, which reduces the footprint and lateral size while maintaining a relatively thin package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the package size is reduced to meet compact device requirements, then the footprint and lateral dimensions improve, but the structural complexity increases due to the need for polymer frame, cap layer, and cavity integration
Solution Approach 1:
The polymer frame and cap layer are integrated into a single polymer component that simultaneously provides mechanical support, defines the cavity, and enables acoustic wave propagation. This merging of structural elements reduces the number of discrete parts while achieving compact dimensions.
Solution Approach 2:
The acoustic cavity is formed by transitioning from a planar two-dimensional structure to a three-dimensional structure with vertical depth. The cavity extends in the z-direction between the acoustic device and polymer cap layer, allowing volume optimization without increasing lateral footprint.
2Reliability
If a polymer cap layer is added to enclose the acoustic device, then the protection and sealing improve, but the package thickness increases
Solution Approach 1:
A thin polymer cap layer is used to enclose the acoustic device, providing protection and sealing while minimizing thickness. The polymer material allows for a thin-film structure that maintains reliability without significantly increasing package depth.
Solution Approach 2:
The acoustic device is nested within the polymer frame structure, with the cavity formed inside the polymer body. This nesting arrangement allows the cap layer to be integrated into the existing polymer structure rather than added as a separate external layer.
3Reliability
If the cavity depth is increased to improve acoustic performance, then the signal filtering improves, but the package volume increases
Solution Approach 1:
The cavity is optimized by utilizing the vertical dimension (z-direction) between the acoustic device and polymer cap layer. This allows sufficient cavity depth for acoustic wave propagation and signal filtering performance without increasing the lateral footprint, as the volume expansion occurs primarily in the thickness direction.
Data Source
AI summary
A package comprising an acoustic device, a polymer frame coupled to the acoustic device, a plurality of frame interconnects located in the polymer frame, where the plurality of frame interconnects are coupled to the acoustic device, a polymer cap layer coupled to the acoustic device though the polymer frame, where the polymer cap layer is configured as a cap for the acoustic device, a plurality of cap interconnects located in the polymer cap layer, where the plurality of cap interconnects are coupled to the plurality of frame interconnects, and a cavity located between the acoustic device and the polymer cap layer. The acoustic device includes a substrate and an acoustic element coupled to the substrate.