Shielded Via Structure Reducing Mutual Inductance in Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional through-silicon via (TSV) structures in electronic substrates face challenges with mutual inductance and eddy current losses, which affect the functionality and efficiency of electrical packages, and current solutions either increase space between TSVs or require complex calculations to mitigate these issues.
Innovation Solution
The implementation of a via structure with a shield layer, comprising a conductive layer, an insulating layer, and a salicide film, which reduces mutual inductance and eddy current losses by separating the conductive and insulating layers and coupling the salicide film to a metal layer, allowing signals of opposite polarities to pass through different conductive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the space between nearby TSVs is increased to reduce mutual inductance, then cross-talk between vertical interconnects is reduced, but the substrate area occupied by TSV arrays increases
Solution Approach 1:
An insulating layer is introduced as an intermediary between adjacent TSVs. This insulating layer acts as a mediator that electrically isolates the TSVs from each other, reducing mutual inductance and cross-talk effects while allowing the TSVs to be placed closer together, thereby reducing the overall substrate area required.
2Ease of manufacture
If conventional TSV structures are used, then fabrication is simpler, but eddy current losses and electromagnetic noise increase
Solution Approach 1:
The TSV structure is segmented into multiple functional layers: a conductive core layer for signal transmission, an insulating layer surrounding the core, and an outer conductive shield layer. This segmentation allows the insulating layer to interrupt eddy current paths in the substrate while the conductive layers maintain signal integrity, thereby reducing eddy current losses without significantly complicating the fabrication process.
3Area of stationary object
If TSVs are placed closer together to reduce substrate area, then space efficiency improves, but mutual inductance and electromagnetic interference increase
Solution Approach 1:
The insulating layer serves as a protective intermediary between closely spaced TSVs, enabling high-density TSV placement while mitigating mutual inductance and electromagnetic interference through electrical isolation.
Solution Approach 2:
The harmful electromagnetic fields and eddy currents are extracted or contained within the insulating layer barrier, preventing them from affecting adjacent TSVs and allowing closer spacing without increasing interference.
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 configuration significantly reduces mutual inductance and eddy current losses, enabling TSVs to be placed closer together without increasing space, thereby improving the operational efficiency and reducing electromagnetic noise in electronic substrates.
Implementation Method 1
Eddy currents are formed in the substrate due to changing magnetic fields. As electrical current passes through the TSV, for example, magnetic and electric fields form around the TSV and penetrate the substrate. Changes in the current passing through the TSV may cause changes in the magnetic and electric fields within the substrate. Eddy currents can create an induced magnetic field that opposes the changes in the magnetic field in the substrate.
Implementation Method 2
mutual inductance between nearby TSVs can cause cross-talk, which in some instances can negatively impact the operation of the electrical package
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system of via structures disposed in a substrate. The system includes a first via structure that comprises an outer conductive layer, an inner insulating layer, and an inner conductive layer disposed in the substrate. The outer conductive layer separates the inner insulating layer and the substrate and the inner insulating layer separates the inner conductive layer and the outer conductive layer. A first signal of a first complementary pair passes through the inner conductive layer and a second signal of the first complementary pair passes through the outer conductive layer. In different embodiments, a method of forming a via structure in an electronic substrate is provided.