Planar Package Filtering Circuit for EMI RFI Mitigation
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Solution Overview
Problem
Current packaging solutions for electronic devices face challenges in mitigating high-frequency noise due to the z-height constraints of discrete filtering components, which limits their ability to effectively suppress electromagnetic interference (EMI) and radio frequency interference (RFI), especially in miniaturized packages where conventional discrete components cannot be accommodated.
Innovation Solution
The implementation of a planar filtering circuit within the foundation layer of semiconductor packages, utilizing conductive traces patterned to form equivalent circuits of inductors and capacitors, such as meanders and inter-digital fingers, which reduces the z-height requirement and eliminates the need for discrete components, thereby enabling effective noise filtering without increasing package height or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If discrete filtering components are used to suppress high-frequency noise, then EMI and RFI mitigation is improved, but package z-height increases
Solution Approach 1:
The patent merges the filtering function with the foundation layer structure by patterning conductive traces directly on the foundation layer to form equivalent inductor and capacitor circuits. This integration eliminates the need for separate discrete filtering components, achieving EMI/RFI suppression without increasing package z-height.
Solution Approach 2:
The invention transitions from three-dimensional discrete components (capacitors and inductors with height) to two-dimensional planar patterns on the foundation layer. By using meander lines, inter-digital fingers, and spiral patterns, the filtering function is achieved in the planar domain, reducing the z-height requirement to near-zero.
2Object-affected harmful factors
If discrete filtering components are used, then noise suppression is improved, but device complexity increases
Solution Approach 1:
The filtering functionality is merged into the foundation layer itself through conductive trace patterns. Instead of adding separate inductors, capacitors, and their associated mounting hardware, the foundation layer is patterned to directly provide the equivalent filtering circuit, reducing component count and assembly complexity.
Solution Approach 2:
The foundation layer serves multiple functions: it provides mechanical support, electrical connectivity, and now also EMI/RFI filtering. By making the foundation layer multi-functional, the patent eliminates the need for dedicated discrete filtering components, simplifying the overall device structure.
3Object-affected harmful factors
If conventional filtering components are used, then EMI RFI mitigation is achieved, but manufacturing cost increases
Solution Approach 1:
The filtering function is combined with the foundation layer manufacturing process. The conductive traces are patterned using standard PCB fabrication techniques, allowing the filtering structure to be produced in the same manufacturing run as the foundation layer itself, eliminating separate component procurement and assembly costs.
Solution Approach 2:
The foundation layer serves itself by providing both structural support and filtering functionality. The conductive patterns are formed as integral parts of the foundation layer, eliminating the need for external filtering components and their associated assembly operations, thereby reducing manufacturing complexity and cost.
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 solution effectively suppresses EMI and RFI noise while reducing the overall package height and complexity, improving noise reduction and cost efficiency by minimizing parasitic inductance and simplifying manufacturing, and is suitable for smaller form factors where discrete components are not feasible.
Implementation Method 1
The planar filtering circuit includes one or more conductive traces that are patterned to form an equivalent circuit of inductors and capacitors
Data Source
AI summary
A semiconductor package and a packaged electronic device are described. The semiconductor package has a foundation layer and a planar filtering circuit. The circuit is formed in the foundation layer to provide EMI/RFI mitigation. The circuit has one or more conductive traces that are patterned to form an equivalent circuit of inductors and capacitors. The one or more conductive traces include planar metal shapes, such as meanders, loops, inter-digital fingers, and patterned shapes, to reduce the z-height of the package. The packaged electronic device has a semiconductor die, a foundation layer, a motherboard, a package, and the circuit. The circuit removes undesirable interferences generated from the semiconductor die. The circuit has a z-height that is less than a z-height of solder balls used to attach the foundation layer to the motherboard. A method of forming a planar filtering circuit in a foundation layer is also described.