Flex-foil Package Coplanar Topology for High-Frequency Signals
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Solution Overview
Problem
Conventional electronic device packages are limited by standardization specifications, making it difficult to achieve miniaturization with reduced package height and increased flexibility while maintaining high-frequency signal bandwidth, and they often require complex and costly manufacturing processes.
Innovation Solution
A foil-based package with a patterned electrically conductive layer featuring coplanar waveguides and an equipotential surface, allowing for ultra-thin and flexible designs with reduced overall thickness, enabling efficient signal guiding for high-frequency signals without bond wires and using a casting compound to enclose the package terminal pads and electronic device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional standardized packages (SMD, QFN, CSP, BGA) are used, then compatibility with standardization specifications is ensured, but package height is limited to more than 300 μm and flexibility is not achieved
Solution Approach 1:
The patent employs a foil substrate as the package structure, replacing conventional rigid package forms with a flexible thin-film structure. This foil substrate enables the package to achieve flexibility and be bent without damage, while reducing the package height to below 300 μm, thereby resolving the contradiction between flexibility and package height limitations of standardized packages.
2Volume of moving object
If package miniaturization is pursued to reduce size, then structural height is reduced, but wiring lengths increase and exceed lambda/4 length for high-frequency signals
Solution Approach 1:
The patent transitions from planar two-dimensional trace structures to three-dimensional coplanar waveguide structures. By arranging signal-guiding and reference electrically conducting portions in coplanar configuration with controlled spacing, the waveguides provide optimized signal paths that maintain appropriate electrical lengths for high-frequency signals while accommodating miniaturized package dimensions, thus resolving the contradiction between package size reduction and high-frequency signal integrity.
3Productivity
If I/O pad size and distance are reduced to increase pad count, then pad pitch decreases, but manufacturing precision requirements increase due to punch tool limitations
Solution Approach 1:
The patent changes the manufacturing approach from conventional punch-based lead frame fabrication to foil substrate processing with patterned electrically conducting layers. This parameter change in manufacturing methodology enables the realization of smaller pad geometries and tighter pad pitches that were previously unachievable with punch tools, thereby increasing the number of I/O pads while maintaining manufacturing feasibility.
4Reliability
If coplanar waveguide topology is implemented for high-frequency signals, then signal bandwidth is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the signal-guiding function and the reference potential function into a coplanar configuration on the same foil substrate plane. By integrating the signal-guiding electrically conducting portion and reference electrically conducting portion in a coplanar topology, the structure provides optimized high-frequency signal transmission while maintaining a relatively simple manufacturing process that does not require complex multi-layer interconnections or three-dimensional trace routing.
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
The solution enables a flexible and ultra-thin package that can be bent without damage, achieving high-frequency signal bandwidth and reduced manufacturing costs, while maintaining compatibility with conventional standardization criteria.
Implementation Method 1
the first electrically conducting portion is implemented to be a signal-guiding waveguide for high-frequency signals
Implementation Method 2
the second electrically conducting portion, which is coplanar to the first electrically conducting portion, and the third electrically conducting portion, which is coplanar to the first electrically conducting portion, form an equipotential surface
Data Source
AI summary
The invention relates to a foil-based package with at least one foil substrate having an electrically conductive layer arranged thereon which is patterned to provide a first electrically conducting portion and a second electrically conducting portion, which is coplanar to the first electrically conducting portion, and a third electrically conducting portion, which is coplanar to the first electrically conducting portion, the first electrically conducting portion being arranged between the second and third electrically conducting portions. In accordance with the invention, the first electrically conducting portion is implemented to be a signal-guiding waveguide for high-frequency signals and the second electrically conducting portion, which is coplanar to the first electrically conducting portion, and the third electrically conducting portion, which is coplanar to the first electrically conducting portion, form an equipotential surface.