Package Substrate Floating Wiring Layout for Crosstalk Reduction
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Solution Overview
Problem
Crosstalk noise caused by electromagnetic coupling between signal wiring patterns limits signal quality and transmission speed in package substrates and semiconductor packages, particularly in high-capacity and high-speed signal transmission.
Innovation Solution
Intentionally adding capacitance to the wiring pattern by incorporating a floating wiring pattern in the second layer of the package substrate, which overlaps with the pads, to counteract the dominant influence of inductance and reduce crosstalk noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If signal wiring patterns are used for high-capacity and high-speed signal transmission, then signal transmission speed and capacity are improved, but crosstalk noise increases due to electromagnetic coupling between the wiring patterns
Solution Approach 1:
A floating wiring pattern is introduced as an intermediary element between the signal wiring patterns. This floating wiring pattern does not carry signal but serves as a mediator to adjust the electromagnetic coupling characteristics. By positioning the floating wiring pattern at specific locations, the electromagnetic field distribution is modified, thereby reducing crosstalk noise between adjacent signal wires while maintaining high-speed signal transmission capability
Solution Approach 2:
The invention changes the electromagnetic parameters of the wiring structure by adding floating wiring patterns with specific geometries and positions. This modifies the inductance and capacitance characteristics of the signal transmission paths, adjusting the impedance matching and reducing electromagnetic coupling. The parameter changes are achieved through controlled variations in the floating wiring pattern's area, shape, and location relative to the signal wires
2Object-affected harmful factors
If the area of the floating wiring pattern is increased to reduce crosstalk noise, then crosstalk noise is reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The floating wiring pattern is segmented into multiple discrete regions or shapes rather than using a single large continuous area. This segmentation allows the design to achieve the required capacitance effect for crosstalk reduction while maintaining simpler manufacturing processes. The segmented structure can be more easily integrated into existing fabrication workflows and requires less precise control over large-area patterning
Solution Approach 2:
Instead of uniformly increasing the floating wiring pattern area across the entire substrate, the invention applies floating wiring patterns with optimized local areas and shapes at specific locations where crosstalk is most problematic. This local quality approach ensures that the capacitance is added precisely where needed for maximum crosstalk reduction while minimizing the overall added complexity and manufacturing burden
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 effectively reduces crosstalk noise, thereby improving signal characteristics such as quality and speed in high-speed signal transmission.
Implementation Method 1
intentionally adding capacitance to a wiring pattern in which the influence of inductance is dominant
Implementation Method 2
Crosstalk noise is a phenomenon caused by electromagnetic coupling between signal wiring patterns
Data Source
AI summary
A package substrate includes a plurality of layers, each layer of the plurality of layers including a respective conductive pattern. The plurality of layers includes a first layer in which a first conductive pattern and a plurality of pads exposed externally with respect to the package substrate are disposed, a second layer located above the first layer, and including a second conductive pattern and a floating wiring pattern having an area overlapping the plurality of pads, and a third layer located above the second layer, and including a third conductive pattern.