Multi-Finger IC Layout for Electromigration Mitigation
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Solution Overview
Problem
Integrated circuits are susceptible to electromigration due to high current density and increased device temperature, leading to circuit failures and reliability issues as a result of atomic flux causing voids and metal disintegration.
Innovation Solution
The integrated circuit layout includes a P-type and N-type active region with specific metal connections and trunks arranged in a multi-finger configuration, with wider trunks and conductive vias to distribute current effectively, reducing the risk of electromigration by perpendicular connections to power supply lines and transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If narrower interconnection lines and smaller contacts are used to increase device density, then more devices can be compressed in integrated circuits to improve performance, but current density increases causing electromigration susceptibility
Solution Approach 1:
The interconnection structure is divided into multiple segments including interconnect lines, contacts, and via structures. By segmenting the current path and distributing current flow across multiple parallel interconnect lines and contacts, the current density on any single segment is reduced, thereby mitigating electromigration effects while maintaining high device density
Solution Approach 2:
Different regions of the interconnection structure are designed with locally optimized properties. Wider interconnect lines are used in regions with higher current density, while smaller dimensions are used where space is constrained. Contact dimensions and via structures are locally adjusted to optimize current distribution and reduce electromigration susceptibility in specific high-stress areas
2Productivity
If higher current density is used to maintain compact design, then device density is improved, but resistance increases causing self-heating and metal disintegration
Solution Approach 1:
The current path is segmented into multiple parallel interconnect lines and contacts, distributing the total current across multiple pathways. This reduces the current density in each segment, thereby reducing resistive heating (I²R losses) and preventing self-heating and metal disintegration while maintaining compact device density
Solution Approach 2:
The interconnection structure utilizes multiple metal layers and vertical via structures to create three-dimensional current distribution. By routing current through multiple layers and via paths, the effective cross-sectional area for current flow is increased, reducing current density and associated self-heating effects in the compact device footprint
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 enhances the reliability and operating frequency of semiconductor circuits by mitigating the effects of electromigration, reducing the likelihood of circuit failures and improving current distribution.
Implementation Method 1
EM is a phenomenon that, at higher current density and/or increased device temperature, causes electron momentum to be transferred to atoms in thin film metallic conductors (e.g., signal nets) causing a net atomic flux
Implementation Method 2
A third metal connection is disposed over and is electrically connected with the first and the second metal connections through at least two conductive vias
Data Source
AI summary
An integrated circuit layout includes a P-type active region, an N-type active region, a first metal connection, a second metal connection and a plurality of trunks. The plurality of trunks is formed substantially side-by-side, and in parallel with each other. The first metal connection is substantially disposed over the P-type active region, and is electrically connected with drain regions of PMOS transistors in the P-type active region. The second metal connection is substantially disposed over the N-type active region, and is electrically connected with drain regions of NMOS transistors in the N-type active region. The plurality of trunks is electrically connected with and is substantially perpendicular to the first metal connection and the second metal connection. A first trunk of the plurality of trunks has a width wider than a width of other trunks of the plurality of trunks and is arranged to be located between two groups of trunks.