FBAR Packaging Structure With Elastic Bonding and Through-Hole Interconnect
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Solution Overview
Problem
Current packaging processes for film bulk acoustic resonators are complex, costly, and introduce material pollution due to gold bonding, and result in insufficient mechanical strength of the resonator cover, posing reliability risks.
Innovation Solution
A packaging method using an elastic bonding material layer on a second substrate, which is bonded to the resonant cavity main structure, forming a through-hole and conductive interconnection layer to align and secure the film bulk acoustic resonant structure, eliminating the need for gold bonding and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Au-Au bonding process is used to bond the carrier substrate with the resonant cavity main structure, then the bonding strength is improved, but the material cost increases and element pollution is introduced
Solution Approach 1:
The patent replaces expensive gold bonding material with a disposable polyimide tape that serves as a temporary bonding medium during the packaging process. The polyimide tape is inexpensive, easily removable, and eliminates the need for costly Au-Au bonding while preventing gold element pollution in the production line.
Solution Approach 2:
The patent substitutes the thermal Au-Au bonding process with a mechanical bonding approach using polyimide tape. Instead of relying on thermal diffusion bonding of gold layers, the invention uses the adhesive properties of polyimide tape to temporarily hold components together, eliminating the need for complex thermal bonding equipment and processes.
2Strength
If Au-Au bonding process is used to bond the carrier substrate with the resonant cavity main structure, then the bonding strength is improved, but the production line is polluted with gold elements
Solution Approach 1:
The patent replaces expensive gold bonding material with a disposable polyimide tape that serves as a temporary bonding medium during the packaging process. The polyimide tape is inexpensive, easily removable, and eliminates the need for costly Au-Au bonding while preventing gold element pollution in the production line.
Solution Approach 2:
The patent substitutes the thermal Au-Au bonding process with a mechanical bonding approach using polyimide tape. Instead of relying on thermal diffusion bonding of gold layers, the invention uses the adhesive properties of polyimide tape to temporarily hold components together, eliminating the need for complex thermal bonding equipment and processes.
3Ease of manufacture
If a thin passivation layer is deposited to form the upper cavity cover, then the manufacturing process is simplified, but the mechanical strength is insufficient
Solution Approach 1:
The patent creates a composite structure by bonding the resonant cavity main structure to a carrier substrate using polyimide tape. This composite construction provides enhanced mechanical strength to the upper cavity cover compared to using a thin passivation layer alone, while still maintaining manufacturing simplicity through the use of standard bonding processes.
4Adaptability or versatility
If the carrier substrate is removed after bonding to form the final structure, then the device design is achieved, but the process complexity increases
Solution Approach 1:
The patent performs preliminary bonding of the resonant cavity main structure to the carrier substrate using polyimide tape before final assembly. This preliminary action allows for easy alignment and positioning, and the carrier substrate can be conveniently removed after bonding without affecting the bonded components, thereby simplifying the overall process despite the additional step.
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 method simplifies the packaging process, reduces material costs, and improves the mechanical strength and reliability of the film bulk acoustic resonator by eliminating gold bonding and ensuring stable electrical connections.
Implementation Method 1
bonding the resonant cavity main structure and the resonator cover together through the elastic bonding material layer
Implementation Method 2
forming a conductive interconnection layer... ensures stable electrical connections
Data Source
AI summary
A packaging method and a packaging structure of a film bulk acoustic resonator are provided. The packaging method includes: providing a resonant cavity main structure including a first substrate and a film bulk acoustic resonant structure having a first cavity formed therebetween; forming a resonator cover by providing a second substrate and forming an elastic bonding material layer containing a second cavity and an initial opening; bonding the resonant cavity main structure and the resonator cover together through the elastic bonding material layer and removing elasticity of the elastic bonding material layer, where the second cavity is at least partially aligned with the first cavity; forming a through-hole containing the initial opening and a hole connected with the initial opening and passing through the resonator cover; and forming a conductive interconnection layer covering a sidewall of the through-hole and a portion of a surface of the resonator cover.