Porous Package Substrate Dielectric Layers for Crosstalk Reduction
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Solution Overview
Problem
High-frequency semiconductor packages using multilayer substrates experience performance issues due to crosstalk caused by capacitive and inductive coupling between adjacent metal lines, particularly in transmission lines connected to antennas, which is not effectively addressed by conventional dielectric layers.
Innovation Solution
The introduction of porous dielectric layers with a polymeric material and an average porosity of at least 5% reduces crosstalk by lowering the dielectric constant, achieved through the use of sacrificial polymer materials that decompose during curing, forming pores in the dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric layers are used in multilayer package substrates, then the structure provides adequate mechanical support and electrical insulation, but crosstalk due to capacitive and inductive coupling between adjacent metal lines increases, degrading high-frequency signal performance
Solution Approach 1:
The patent applies porous dielectric materials with porosity of at least 5% (and preferably at least 10%) to reduce the dielectric constant of the insulation layers. The porous structure lowers the capacitive coupling between adjacent metal lines, thereby reducing crosstalk and improving high-frequency signal transmission quality without compromising mechanical support or electrical insulation functions.
Solution Approach 2:
The patent changes the physical and electrical parameters of the dielectric material by introducing porosity (at least 5%, preferably at least 10%). This parameter change reduces the dielectric constant, which directly lowers capacitive coupling and inductive coupling effects between metal lines, thereby reducing crosstalk while maintaining adequate mechanical and electrical insulation properties.
2Speed
If the dielectric constant is reduced to lower crosstalk, then signal transmission speed improves, but the dielectric layer's ability to provide electrical insulation and mechanical support may be compromised
Solution Approach 1:
The patent uses porous dielectric materials that achieve the dual benefit of reduced dielectric constant (improving signal speed) and maintained structural integrity. The controlled porosity (at least 5%, preferably at least 10%) lowers capacitive and inductive coupling to enhance signal transmission speed while the porous structure is designed to maintain adequate mechanical support and electrical insulation strength.
Solution Approach 2:
The patent employs composite dielectric materials combining porous structures with appropriate matrix materials to achieve optimized electrical and mechanical properties. The composite structure provides reduced dielectric constant for faster signal transmission while maintaining the strength and insulation properties necessary for structural support in the multilayer package substrate.
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 porous dielectric layers effectively mitigate crosstalk, enhancing the electrical performance of semiconductor packages by improving signal transmission speed and reducing interference between adjacent metal lines, particularly in high-frequency applications like 5G technology.
Implementation Method 1
achieved through the use of sacrificial polymer materials that decompose during curing, forming pores in the dielectric layers
Implementation Method 2
The lowering of the dielectric constant is implemented by the porous dielectric layer having a significant level of porosity, including a plurality of pores providing an average porosity of at least 5% over the thickness of the porous dielectric layer
Data Source
AI summary
A multilayer package substrate includes a plurality of dielectric layers including a top dielectric layer on a top side and a bottom dielectric layer on a bottom side. A top patterned metal layer is on the top dielectric layer and a bottom patterned metal layer is on the bottom dielectric layer. At least one of the top dielectric layer and the bottom dielectric layer is a porous dielectric layer having a plurality of pores including an average porosity of at least 5% averaged over its thickness.