Pseudo-Stripline IC Package Routing for EMI-Shielded High-Speed I/O
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Solution Overview
Problem
Next-generation multi-chip packaging requires higher interconnect density and reduced electromagnetic interference (EMI) shielding, while also aiming to minimize the number of metallization levels in IC device packages to reduce thickness and cost, posing a challenge as conventional microstrip architectures offer less protection from EMI and are not suitable for high-speed I/O signals.
Innovation Solution
Implementing a pseudo-stripline signal routing architecture by augmenting the top metallization level with a redistribution layer (RDL) and adding a ground plane within the routing structure, which is separate from the package substrate, to create a hybrid transmission line architecture that provides EMI shielding without increasing the number of metallization levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a microstrip architecture is used to reduce metallization levels, then the number of metallization levels is reduced, but electromagnetic interference shielding is insufficient for high-speed signals
Solution Approach 1:
The package substrate is divided into distinct functional zones: a first region containing high-speed signal routes with microstrip architecture and a second region containing lower-speed signal routes with stripline architecture. This segmentation allows each region to be optimized for its specific signal requirements, enabling reduced metallization levels for high-speed signals while maintaining EMI shielding for other signals.
Solution Approach 2:
Different transmission line architectures are applied to different regions of the package substrate based on local signal requirements. The first region uses microstrip architecture with fewer metallization levels optimized for high-speed signals, while the second region uses traditional stripline architecture with complete EMI shielding for lower-speed signals. This local quality approach allows the system to achieve both reduced complexity and adequate EMI protection where needed.
2Object-affected harmful factors
If a stripline architecture is used to provide EMI shielding, then electromagnetic interference protection is improved, but the number of metallization levels increases
Solution Approach 1:
The package substrate is divided into distinct functional zones: a first region containing high-speed signal routes with microstrip architecture and a second region containing lower-speed signal routes with stripline architecture. This segmentation allows each region to be optimized for its specific signal requirements, enabling reduced metallization levels for high-speed signals while maintaining EMI shielding for other signals.
Solution Approach 2:
Different transmission line architectures are applied to different regions of the package substrate based on local signal requirements. The first region uses microstrip architecture with fewer metallization levels optimized for high-speed signals, while the second region uses traditional stripline architecture with complete EMI shielding for lower-speed signals. This local quality approach allows the system to achieve both reduced complexity and adequate EMI protection where needed.
3Length of stationary object
If the number of metallization levels is reduced to decrease package thickness, then package thickness is reduced, but EMI shielding capability is compromised
Solution Approach 1:
The package substrate is divided into distinct functional zones: a first region containing high-speed signal routes with microstrip architecture and a second region containing lower-speed signal routes with stripline architecture. This segmentation allows each region to be optimized for its specific signal requirements, enabling reduced metallization levels for high-speed signals while maintaining EMI shielding for other signals.
Solution Approach 2:
Different transmission line architectures are applied to different regions of the package substrate based on local signal requirements. The first region uses microstrip architecture with fewer metallization levels optimized for high-speed signals, while the second region uses traditional stripline architecture with complete EMI shielding for lower-speed signals. This local quality approach allows the system to achieve both reduced complexity and adequate EMI protection where needed.
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 achieves effective EMI shielding for high-speed signals while reducing the number of metallization levels, thereby lowering the thickness and cost of IC device packages, making it suitable for high-bandwidth applications.
Implementation Method 1
adding a ground plane within the routing structure, which is separate from the package substrate, to create a hybrid transmission line architecture that provides EMI shielding
Data Source
AI summary
IC device package routing with metallization features comprising a pseudo-stripline architecture in which the stripline structure is provisioned, in part, by a routing structure separate from routing within the package substrate. A signal route within top metallization level of a package substrate may be electrically shielded, in part, with a metallization feature within a redistribution layer (RDL) of a routing structure that couples one or more IC chips to the package substrate. Accordingly, a package substrate may have fewer levels of metallization, reduced thickness, and/or lower cost while the IC device package still offers excellent EMI performance.