BAW Resonator Packaging Structure for Stable Through-Hole Interconnects
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Solution Overview
Problem
The existing packaging methods for bulk acoustic wave (BAW) resonators face challenges in forming stable electrical connections due to the poor stability of dry films used in through-silicon via processes, leading to poor quality and unstable electrical contacts.
Innovation Solution
A packaging method involving bonding a BAW resonant device to a second substrate with a bonding layer, forming through holes in the first substrate to expose electrical connections, and creating a conductive interconnection layer on the inner surfaces of these holes and the substrate's periphery, thereby stabilizing the electrical contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through-silicon via process is used with dry film, then electrical connections can be established, but the dry film stability is poor leading to poor quality conductive plugs and unstable electrical contacts
Solution Approach 1:
The patent introduces a bonding layer as an intermediary between the first substrate and second substrate. This bonding layer serves as a stable foundation for forming through holes and conductive plugs, replacing the unstable dry film. The bonding layer provides mechanical support and stability during the through-hole etching and conductive material deposition processes, ensuring high-quality electrical connections without relying on dry film stability.
2Ease of manufacture
If through holes are etched in thick dry film, then electrical connections can be made, but process control difficulty increases significantly
Solution Approach 1:
The bonding layer acts as an intermediary substrate that replaces the problematic thick dry film. It provides a controlled and manageable medium for through-hole etching, with better mechanical properties and process control characteristics. The bonding layer's stability and appropriate thickness enable precise etching processes while maintaining ease of manufacture, eliminating the process control difficulties associated with thick dry film.
3Reliability
If conductive materials are deposited on unstable dry film, then electrical connections are formed, but the conductive plugs have poor quality
Solution Approach 1:
The bonding layer serves as a stable intermediary surface for depositing conductive materials. Its structural stability and appropriate surface properties enable high-quality conductive plug formation through standard deposition processes. The bonding layer provides a reliable foundation that ensures good adhesion and electrical conductivity, eliminating the poor conductive plug quality caused by unstable dry film.
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 ensures stable and reliable electrical connections by avoiding the use of through-silicon via processes, improving the quality and stability of the conductive plugs, and enhancing the overall performance of the BAW resonator.
Implementation Method 1
bonding the BAW resonant device to a second substrate at a side of the resonant structure away from the first substrate through a bonding layer
Implementation Method 2
forming a conductive interconnection layer on inner surfaces of the through holes and on a portion of a surface of the first substrate at a periphery of the through holes
Data Source
AI summary
The present disclosure provides a packaging module and packaging method of a BAW resonator. The packaging method includes: bonding a BAW resonant device including a first substrate and a resonant structure provided on the first substrate to a second substrate through a bonding layer; forming through holes exposing corresponding electrical connection portions of the resonant structure at a side of the first substrate; and forming a conductive interconnection layer on inner surfaces of the through holes and on a portion of a surface of the first substrate to avoid steps of etching through holes and depositing conductive materials from the bonding layer, so that a material of the bonding layer can be selected to provide good bonding effect, which helps to reduce the process difficulty, and improves the stability of the through holes and the formed packaging module, thereby improving the performance of the BAW resonator packaging structure.