Electromigration Analysis Using Trapezoidal Voltage Pulses
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Solution Overview
Problem
Current electromigration analysis methods in integrated circuit design fail to accurately identify individual failing areas in signal wire nets, leading to susceptibility to electromigration-induced failures, which are difficult to address early in the design cycle without significant time delays.
Innovation Solution
An electromigration analysis method that maintains topological information by modeling signal wiring with trapezoidal voltage pulses, extracting slew rates and timing information, and comparing local current density parameters to effective limits, allowing for accurate detection of electromigration violations and identification of failing segments without additional driver characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electromigration analysis methods are used, then the analysis can be performed, but the accuracy of identifying individual failing areas in signal wire nets is insufficient
Solution Approach 1:
The signal wire net is divided into individual wire segments, each with its own topological information and electrical characteristics. This segmentation allows the analysis to identify specific failing segments rather than treating the entire net as a single unit, thereby improving the precision of identifying failing areas while maintaining manageable complexity through localized analysis.
Solution Approach 2:
The analysis method applies local quality by considering specific electrical characteristics (current density, resistance, capacitance) for each individual wire segment rather than using uniform parameters for the entire net. This enables accurate identification of localized failing areas by comparing local current density against local electromigration thresholds, improving measurement precision without requiring overly complex global analysis.
2Reliability
If detailed net simulation is performed to verify net failures, then failure verification is possible, but the design cycle time increases significantly
Solution Approach 1:
The method performs preliminary electromigration analysis during the netlist extraction phase, calculating current density and comparing it against thresholds before detailed simulation. This preliminary action identifies potential failing segments early, allowing targeted verification only for segments that exceed thresholds, thereby maintaining reliability while reducing overall design cycle time by avoiding exhaustive simulation of all segments.
Solution Approach 2:
Instead of performing complete detailed simulation on entire nets, the method applies partial action by focusing simulation resources only on wire segments that exceed current density thresholds. This selective approach maintains failure verification accuracy for critical segments while significantly reducing the total simulation time and computational resources required.
3Measurement precision
If current density parameters are estimated during design, then electromigration risks can be identified, but the accuracy of detecting individual failing segments is insufficient
Solution Approach 1:
The netlist is processed to extract individual wire segments with their specific electrical characteristics. By segmenting the analysis at the wire level rather than net level, the method achieves high detection accuracy for individual failing segments while maintaining design efficiency through automated processing of segmented data structures.
Solution Approach 2:
The method replaces complex physical measurement and detailed simulation with an electrical calculation approach based on netlist data. By substituting mechanical/electrical analysis with computational evaluation of extracted netlist parameters (resistance, capacitance, current density), the system achieves high detection accuracy while maintaining productivity through efficient computational processing.
Data Source
AI summary
The invention relates to an electromigration analysis method and a system for analyzing one or more nets in a digital integrated circuit design that are at risk of electromigration. The method comprises the steps of providing at least one interconnect between a driver cell and at least one load cell; applying same extracted netlist data for noise and/or timing analysis and for electromigration analysis; modeling the driver cell by a train of trapezoidal voltage pulses transmitted from the driver cell to the one or more load cells through the at least one interconnect; extracting at least a slew rate of a driver voltage signal and/or timing information from a noise and/or timing analysis for the one or more nets; and comparing a locally measured current density in the at least one interconnect to an effective local maximum current density limit of the at least one interconnect.