Packaged Acoustic Wave Component With Polymer Stress Buffer
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Solution Overview
Problem
The packaging process for multilayer piezoelectric substrate packages in acoustic wave devices applies stresses to the piezoelectric layer, leading to reliability issues such as cracking during heat cycle testing.
Innovation Solution
A packaged acoustic wave component design featuring a substrate, dielectric layer, piezoelectric structure, electrode structure, polymer structure with a cavity, metal structure, and buffer coating, where the polymer structure is sandwiched between the substrate and metal structure to act as a stress buffer, reducing thermal and mechanical stress on the piezoelectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional packaging process is used for multilayer piezoelectric substrate packages, then the packaging can be completed, but the piezoelectric layer experiences stress that causes cracking and reliability issues during heat cycle testing
Solution Approach 1:
A polymer stress buffer layer is introduced as an intermediary component between the rigid packaging structure and the piezoelectric layer. This polymer layer absorbs and distributes mechanical stress, preventing stress concentration on the piezoelectric layer during heat cycle testing and packaging processes, thereby eliminating cracking while maintaining packaging integrity.
2Reliability
If the packaging structure is made more robust to withstand stress, then reliability improves, but the device size increases
Solution Approach 1:
A thin polymer stress buffer layer is used instead of thick rigid protective structures. This flexible thin film provides sufficient stress absorption and mechanical protection while maintaining a compact package size, avoiding the need for bulky protective housings that would increase overall device volume.
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 design enhances the reliability and mechanical ruggedness of the packaged acoustic wave components, preventing cracks and enabling their use in high-power applications while allowing for size reduction.
Implementation Method 1
the polymer structure having a polymer structure lateral portion sandwiched between the substrate, the dielectric layer, or the piezoelectric structure on one side, and both directly the metal structure and directly the buffer coating on the other side
Implementation Method 2
the polymer structure...configured to form a cavity over the electrode structure...acting as a stress buffer, reducing thermal and mechanical stress on the piezoelectric layer
Data Source
AI summary
Disclosed is a packaged acoustic wave component and a method for making a packaged acoustic wave component. The packaged acoustic wave component comprises a substrate, a dielectric layer disposed over the substrate, a piezoelectric structure disposed over the dielectric layer, an electrode structure disposed over the piezoelectric structure, a polymer structure including a polymer structure wall portion and a polymer structure roof portion configured to form a cavity over the electrode structure, a metal structure disposed over the polymer structure, and a buffer coating disposed over the metal structure. The polymer structure includes a polymer structure lateral portion sandwiched between the substrate, the dielectric layer, or the piezoelectric structure on one side, and both the metal structure and the buffer coating on the other side.