Integrated Circuit Metal Interconnect Electromigration Constraint Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As integrated circuit feature sizes decrease and operating temperatures and expected lifetimes increase, electromigration failures become a significant concern due to high direct current densities and temperatures, necessitating effective design constraints to delay these failures until beyond the circuit's lifetime.
Innovation Solution
The method determines maximum direct currents for metal components as design constraints, treating short and long components differently to allow relief from strict electromigration limits, with short components having two maximum currents based on temperature and Blech length, and long components based solely on temperature and lifetime, to optimize design constraints and minimize failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strict electromigration limits are applied to all metal components, then electromigration failures are minimized, but design flexibility and current carrying capacity are reduced
Solution Approach 1:
The patent applies different electromigration design constraints to different metal component types. Short metal components (exhibiting Blech effect) are subject to relaxed constraints allowing higher current densities, while long metal components maintain strict electromigration limits. This local differentiation resolves the contradiction by applying strict limits only where necessary.
Solution Approach 2:
The patent changes the electromigration constraint parameters based on metal component length characteristics. For short components, the design constraint incorporates the Blech effect consideration, allowing higher current densities than for long components. This parameter adjustment enables optimized current carrying capacity while maintaining reliability.
2Productivity
If feature sizes are decreased to improve integration density, then more transistors fit in smaller area, but current density increases and electromigration failures become more likely
Solution Approach 1:
The patent identifies and treats short metal components differently from long ones in the design flow. By recognizing which interconnects are short enough to exhibit the Blech effect, the system applies relaxed electromigration constraints specifically to those segments, allowing higher current densities that compensate for the reduced feature size benefits.
3Productivity
If operating temperature and expected lifetime are increased to meet performance requirements, then circuit functionality is enhanced, but electromigration failures become more prominent
Solution Approach 1:
The patent adjusts electromigration design constraints based on operating temperature and expected lifetime parameters. For short metal components, the system calculates maximum direct currents considering both temperature effects and the Blech effect, allowing optimized current densities that maintain reliability under extended operating conditions.
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 effectively minimizes electromigration failures by selecting the most liberal design constraints for short components while ensuring failure avoidance, reducing the need for repairs and optimizing the design flow processes, thereby extending the integrated circuit's lifespan.
Implementation Method 1
due to the Blech effect exhibited by short metal components, electromigration is not of concern
Implementation Method 2
Electromigration is a condition in which atoms of a metal component are displaced due to the current passing through that metal component. Since electromigration is caused by the collision between electrons and metal ions as direct current passes through the metal component
Data Source
AI summary
Disclosed is an integrated circuit design method that determines maximum direct currents for metal components and uses them as design constraints in the design flow in order to avoid/minimize electromigration failures. Short and long metal components are treated differently for purposes of establishing the design constraints. For a short metal component, the maximum direct current as a function of a given temperature for a given expected lifetime of the integrated circuit is determined, another maximum direct current is determined based on the Blech length, and the higher of these two is selected and used as the design constraint for that short metal component. For a long metal component, only the maximum direct current as a function of the given temperature for the given expected lifetime is determined and used as the design constraint. Also disclosed herein are associated system and program storage device embodiments for designing an integrated circuit.