Electromigration Tolerant Cell Synthesis via Quality Vectors
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Solution Overview
Problem
Electromigration in integrated circuits (ICs) reduces their reliability due to the gradual movement of ions, leading to potential loss of connections and intermittent failures, which are challenging to diagnose and exacerbate with miniaturization, especially in Very Large Scale Integrated (VLSI) circuits, where traditional metrics fail to ensure electromigration-tolerant standard cell layouts.
Innovation Solution
A system and method for designing circuits with improved electromigration characteristics by generating electromigration quality vectors to select optimal circuit placements and routings, using a flowchart process that initializes quality vectors, computes current distributions, and iteratively refines placements and routings to achieve desired electromigration tolerance within design constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metrics are used to evaluate circuit designs, then design development is straightforward, but electromigration tolerance cannot be ensured
Solution Approach 1:
The patent applies preliminary action by computing electromigration quality vectors during the circuit design phase itself, rather than evaluating designs after completion. The system calculates current distribution and electromigration stress for each standard cell placement and routing option beforehand, enabling designers to select electromigration-tolerant configurations from the start. This proactive approach ensures reliability without requiring post-design validation or complex iterative corrections.
2Reliability
If wire widths are increased to avoid electromigration issues, then electromigration resistance improves, but wiring space and circuit area increase
Solution Approach 1:
The patent applies local quality by optimizing each standard cell placement and routing individually based on its specific current distribution and electromigration stress characteristics. Instead of uniformly increasing all wire widths, the system identifies specific locations where electromigration stress is highest and applies targeted optimizations only to those areas. The quality vector calculation considers local current density, cell type, and routing path to determine precise optimization needs, thereby improving electromigration resistance without unnecessarily increasing overall circuit area.
3Productivity
If miniaturization is pursued to increase integration density, then device scaling improves, but electromigration failure probability increases
Solution Approach 1:
The patent applies feedback by implementing an iterative design process where electromigration quality vectors are computed for each standard cell placement and routing configuration, and these results feed back into the design optimization. The system continuously evaluates current distribution patterns, calculates electromigration stress, and uses this feedback to refine placement and routing decisions. This closed-loop approach enables the design to adapt to miniaturization constraints while actively compensating for increased electromigration risk through data-driven optimization at each design iteration.
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 approach effectively identifies and optimizes circuit placements and routings to enhance electromigration tolerance, reducing the likelihood of failures and improving the reliability of ICs by systematically evaluating and refining designs based on electromigration quality criteria.
Implementation Method 1
Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms.
Data Source
AI summary
A method, data processing system, and computer program product are provided for routing a circuit placement a number of times, resulting in a number of routings. An electromigration quality value is computed for each of the routings, and the routing with the best electromigration quality value is selected. In one embodiment, each routing is analyzed with attention to the current that passes through each of the routing's segments in order to compute a current distribution that is used to compute a routing quality vector. In another embodiment, multiple placements are generated and the electromigration placement quality vectors are computed for the various placements with the placement with the best electromigration quality vector being selected. In one embodiment, the placement with the best electromigration quality vector is routed the number of times to determine the routing with the lowest (best) electromigration quality value.