Electromigration Sign-off Tool for Accurate Chip Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electromigration sign-off methods for integrated chips are inefficient as they use a single elevated temperature for all electrical networks, leading to false violations and design overhead, and fail to account for self-heating and resistive heating, making it difficult to optimize chip design effectively.
Innovation Solution
A methodology that determines electromigration violations by performing a single EM check on each electrical network using separate actual temperatures, accounting for real temperature changes due to both self-heating and resistive heating, allowing for a more accurate assessment and reduction of unnecessary design adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single elevated temperature is used for all electrical networks, then the electromigration sign-off process is simplified, but false violations occur and design overhead increases
Solution Approach 1:
The patent segments the electrical networks into different temperature zones based on their actual operating temperatures. Each network is analyzed at its specific temperature rather than using a single elevated temperature for all networks, which eliminates false violations while maintaining process manageability
Solution Approach 2:
The patent applies local quality by assigning different temperature conditions to different electrical networks based on their specific operating characteristics. Networks with higher actual temperatures are analyzed at elevated temperatures, while networks with lower temperatures are analyzed at their actual temperatures, preventing false violations in cooler networks
2Reliability
If separate actual temperatures are used for different electrical networks, then electromigration violation detection accuracy improves, but the sign-off process complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating the actual operating temperatures for each electrical network before conducting the electromigration analysis. This preparation step enables accurate temperature-specific analysis without adding complexity during the actual violation detection process
Solution Approach 2:
The patent changes the temperature parameter for each electrical network based on its actual operating conditions. By dynamically adjusting the analysis temperature to match each network's real operating temperature, the patent achieves high detection accuracy while using systematic parameter management to control process complexity
3Device complexity
If self-heating and resistive heating are not accounted for, then the analysis process is simpler, but temperature accuracy deteriorates leading to incorrect EM assessments
Solution Approach 1:
The patent incorporates feedback by using power consumption data and electrical load information to calculate self-heating and resistive heating effects. This feedback loop adjusts the temperature estimates for each network based on actual operating conditions, ensuring accurate temperature assessments without excessive process complexity
Solution Approach 2:
The patent applies self-service by having each electrical network's temperature determined by its own power consumption characteristics and electrical loads. The analysis process automatically calculates the temperature rise due to self-heating and resistive heating for each network based on its specific operating parameters, eliminating the need for external temperature measurement while maintaining high accuracy
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 approach reduces false EM violations, minimizes design overhead, and optimizes chip design by treating each network differently, thereby enhancing the reliability and efficiency of the electromigration sign-off process.
Implementation Method 1
accounting for real temperature changes due to both self-heating and resistive heating
Implementation Method 2
accounting for real temperature changes due to both self-heating and resistive heating
Data Source
AI summary
The present disclosure relates to a method of performing electromigration sign-off. The method includes determining a change in temperature due to joule heating from an RMS current of a first interconnect. The change in temperature due to joule heating is added to a change in temperature due to device self-heating to determine a first change in real temperature. A first average current limit is determined for the first interconnect using the first change in real temperature. A first average current on the first interconnect is compared to the first average current limit to determine if a first electromigration violation is present on the first interconnect. A second average current is determined for a second interconnect using a second change in real temperature. The second average current is compared to a second average current limit to determine if a second electromigration violation is present on the second interconnect.