Resistive Signal Lines for Heterogeneous Package Routing
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Solution Overview
Problem
Conventional chip packages with thin organic redistribution layers suffer from undesirable oscillations and crosstalk, leading to poor high-speed data transmission performance compared to silicon interposers.
Innovation Solution
A chip package with a redistribution layer having signal transmission lines with increased resistance and specific configurations, such as non-linear paths or resistive components, to dampen oscillations and reduce crosstalk, thereby improving data transmission performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional redistribution layers use copper lines with low resistance, then signal transmission efficiency is improved, but oscillations and crosstalk increase leading to poor high-speed data transmission performance
Solution Approach 1:
The patent changes the resistance parameter of the signal transmission line by using a resistive material or structure instead of conventional low-resistance copper lines. This parameter change increases the damping effect on oscillations and reduces crosstalk, thereby improving high-speed data transmission performance despite the higher resistance
Solution Approach 2:
The patent employs a composite structure where the signal transmission line incorporates resistive material properties within the organic redistribution layer. This composite approach combines the benefits of organic substrates with controlled resistance characteristics to achieve both mechanical flexibility and electrical performance for high-speed signaling
2Manufacturing precision
If silicon interposers are used to achieve fine line widths and small line pitches, then manufacturing precision is improved, but device complexity and fabrication difficulty increase
Solution Approach 1:
The patent replaces expensive and complex silicon interposers with a simpler organic redistribution layer structure. While silicon interposers provide fine pitch capability, the organic RDL offers a cost-effective and less complex alternative that achieves adequate precision for the application without requiring through-silicon-via fabrication processes
Solution Approach 2:
Instead of using a rigid silicon substrate to achieve precision routing, the patent inverts the approach by using a flexible organic material with embedded resistive elements. This inversion allows for simplified fabrication processes while achieving the necessary signal transmission characteristics through material property optimization rather than geometric 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 solution enhances data transmission reliability and noise margins by effectively reducing oscillations and crosstalk, achieving improved performance in high-speed inter-die connections.
Implementation Method 1
The first signal transmission line has a resistance greater than an equivalent base resistance of a copper line... effectively reducing oscillations
Implementation Method 2
The first signal transmission line has a resistance greater than an equivalent base resistance of a copper line... reducing crosstalk
Data Source
AI summary
A chip package and method of fabricating the same are described herein. The chip package includes a high speed data transmission line that has an inter-die region through which a signal transmission line couples a first die to a second die. The signal transmission line has a resistance greater than an equivalent base resistance (EBR) of a copper line, which reduces oscillation within the transmission line.