Cavity Filter SiP Layout to Prevent Solder Bridging
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Solution Overview
Problem
Conventional diversity reception modules in wireless networks face issues with solder-bridging short circuits and insufficient filling of non-filter chips due to film covering, leading to reliability concerns and high power consumption.
Innovation Solution
A cavity filter system-in-package module with a substrate having a groove, a first flip chip mounted in the groove, a solder mask layer surrounding the flip chips, and a discontinuous film layer covering the second flip device, ensuring proper filling and avoiding solder-bridging through strategic gap and distance management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous film layer is formed over all chips, then cavity formation is ensured, but solder-bridging short circuits occur between devices
Solution Approach 1:
The patent implements local quality by making the film layer continuous only over filter chips and discontinuous over non-filter chips. This localized approach ensures cavities are maintained where needed (filter chips) while allowing molding compound to provide electrical isolation where needed (non-filter chips), thus preventing solder-bridging without compromising cavity formation.
2Ease of manufacture
If non-filter chips are insufficiently filled with molding compound, then film covering is maintained, but reliability of non-filter chips cannot be ensured
Solution Approach 1:
The patent extracts the film covering from non-filter chip regions, leaving them uncovered or partially covered. This extraction allows the molding compound to fully fill the spaces around non-filter chips, ensuring proper mechanical support and electrical isolation, thereby guaranteeing their reliability while simplifying the manufacturing process.
Data Source
AI summary
The cavity filter system-in-package module comprises a substrate, a first flip chip, a second flip device, a film layer, and a plastic encapsulant, wherein the substrate is provided with a groove, which extends from an upper surface of the substrate towards the interior of the substrate down to the layer where a second layer pattern is located or below; the first flip chip is mounted or soldered within the groove; the second flip device is mounted or soldered on the upper surface of the substrate; the first flip chip and the second flip device are surrounded by a solder mask layer; and a continuous film layer is formed on the surface of the first flip chip and the solder mask layer, and the film layer on the surface of the second flip device and the solder mask layer is discontinuous.