FBAR Filter Grounding Layout for Wire-Bond Parasitic Control
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Solution Overview
Problem
The assembly and interconnection of Film Bulk Acoustic Resonator (FBAR) filters face challenges such as heavy adjusting workloads, low working efficiency, undesignability, and difficulty in achieving optimal performance due to the impact of wire bonding on out-band filtering performance.
Innovation Solution
A method is developed to assemble and interconnect FBAR filters by constructing an equivalent circuit model, simulating and calculating the grounding circuit to extract parasitic parameters, and adjusting these parameters to optimize the S parameter performance of the FBAR filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is used to connect FBAR filter, then electrical connection is achieved, but out-band filtering performance deteriorates due to parasitic inductance
Solution Approach 1:
The patent extracts and models the parasitic inductance of the wire bonding separately in an equivalent circuit model. By identifying and isolating this harmful parasitic element, the design can compensate for its effects through parameter optimization, thus maintaining electrical connection while mitigating its negative impact on out-band filtering performance
Solution Approach 2:
The patent optimizes the wire bonding parameters (such as wire length, diameter, and bonding configuration) to minimize parasitic inductance. By changing these physical parameters, the harmful effects on out-band filtering performance are reduced while preserving the necessary electrical connection function
2Reliability
If continuous adjusting of wire bonding configuration is performed, then optimal performance may be achieved, but adjusting workload increases and working efficiency decreases
Solution Approach 1:
The patent performs preliminary modeling and simulation of different wire bonding configurations before actual manufacturing. By predicting the performance outcomes in advance through equivalent circuit modeling, the optimal configuration can be selected without extensive trial-and-adjustment, thus improving working efficiency while achieving optimal performance
Solution Approach 2:
The patent creates an equivalent circuit model that copies and simulates the electrical behavior of the physical wire bonding configuration. This virtual model allows for rapid evaluation of different configurations without physical adjustments, reducing adjusting workload while identifying optimal performance parameters
3Reliability
If wire bonding configuration is adjusted based on historical experience, then performance optimization is attempted, but undesignability and difficulty to achieve optimal performance occur
Solution Approach 1:
The patent replaces empirical, experience-based adjustment methods with a systematic equivalent circuit modeling approach. This modeling system provides a theoretical framework for designing wire bonding configurations, making the design process more predictable and achievable without relying solely on historical experience
Solution Approach 2:
The patent establishes a feedback loop where the equivalent circuit model predicts performance based on wire bonding parameters, and these predictions guide parameter optimization. This iterative feedback process enables systematic achievement of optimal performance rather than random adjustment based on experience
Data Source
AI summary
The disclosure provides a method for assembling and interconnecting FBAR filter and an electronic device. The method includes constructing an equivalent circuit model of an assembled FBAR filter according to a circuit model of a filter chip and the grounding circuit of the FBAR filter; modeling, simulating and calculating the grounding circuit to extract parasitic parameters corresponding to the grounding pad and a grounding bond-wire of the grounding circuit, respectively; feedbacking the parasitic parameters back into the equivalent circuit model, and using the circuit simulation software to obtain an S parameter of the filter; adjusting the parasitic parameters of the grounding circuit to optimize an S parameter performance of the FBAR filter: obtaining an optimal assembly configuration of the FBAR filter to guide the assembly. The parasitic parameters include a parasitic inductance of the grounding bond-wire and a parasitic capacitance and parasitic inductance of the grounding pad.