RDL Conductive Trace Shielding for Lower Crosstalk
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Solution Overview
Problem
Conventional semiconductor packaging technologies face challenges in reducing crosstalk and enhancing signal integrity in redistribution layers (RDLs) due to the lack of effective shielding mechanisms for conductive traces.
Innovation Solution
Implementing conductive lines of varying thicknesses, where thicker lines act as electromagnetic shields for thinner lines within the same dielectric layer, reducing crosstalk and improving signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RDL structures are used without shielding mechanisms, then device complexity is reduced and manufacturing is easier, but crosstalk increases and signal integrity deteriorates
Solution Approach 1:
The patent applies local quality by varying the thickness of conductive lines within the same dielectric layer. Thicker conductive lines are strategically positioned to serve as electromagnetic shields for thinner signal lines, creating localized zones of enhanced shielding without requiring additional dielectric layers or complex multi-layer structures. This selective variation in line thickness provides targeted electromagnetic protection where needed while maintaining overall structural simplicity.
Solution Approach 2:
The patent implements multi-functionality by enabling conductive lines to serve dual purposes: thinner lines function as signal transmission paths, while thicker lines simultaneously serve as both power/ground connections and electromagnetic shields. This eliminates the need for dedicated shield layers, as the same conductive infrastructure performs multiple functions including signal routing, power distribution, and crosstalk reduction, thereby improving signal integrity without proportionally increasing device complexity.
2Object-affected harmful factors
If thicker conductive lines are added as shields in the same dielectric layer, then crosstalk is reduced and signal integrity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by modifying the thickness parameter of conductive lines within the same dielectric layer to create shielding structures. Thicker lines (with increased cross-sectional area) are formed alongside thinner signal lines, leveraging the physical parameter of line thickness to provide electromagnetic shielding. This approach reduces crosstalk by utilizing the natural electromagnetic field distribution around conductors of varying dimensions, achieving shielding effectiveness through parameter variation rather than adding complex structural elements that would demand higher manufacturing precision.
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 use of thicker conductive lines as shields significantly reduces near-end and far-end crosstalk by 3.2 dB and 7.7 dB respectively, enhancing signal integrity in semiconductor devices.
Implementation Method 1
thicker lines act as electromagnetic shields for thinner lines within the same dielectric layer, reducing crosstalk and improving signal integrity
Data Source
AI summary
A method includes forming a dielectric layer over a contact pad of a device, forming a first polymer layer over the dielectric layer, forming a first conductive line and a first portion of a second conductive line over the first polymer layer, patterning a photoresist to form an opening over the first portion of the second conductive feature, wherein after patterning the photoresist the first conductive line remains covered by photoresist, forming a second portion of the second conductive line in the opening, wherein the second portion of the second conductive line physically contacts the first portion of the second conductive line, and forming a second polymer layer extending completely over the first conductive line and the second portion of the second conductive line.