Interconnect Impedance Verification via Analysis Window Filtering
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Solution Overview
Problem
Current electronic design automation tools face challenges in efficiently determining whether interconnect lines in integrated circuit designs have impedance component values below a maximum specified value, particularly for electrostatic damage protection circuits, due to resource-intensive parasitic extraction analysis processes.
Innovation Solution
The implementation of an analysis window based on the characteristics of interconnect lines and specified maximum impedance component values to limit the number of lines analyzed, reducing the workload for parasitic extraction by eliminating those exceeding the maximum value, allowing for efficient determination of remaining lines' impedance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If parasitic extraction analysis is performed on all interconnect lines to verify impedance values, then measurement precision is improved, but productivity deteriorates due to resource-intensive processing
Solution Approach 1:
The patent segments the set of all interconnect lines into two groups: those requiring detailed parasitic extraction analysis and those that can be excluded. This segmentation is achieved by analyzing geometric characteristics (length, width, routing patterns) to identify lines that definitely exceed maximum impedance thresholds, thereby separating them from lines requiring full electrical analysis. This resolves the contradiction by applying full precision only where necessary while maintaining overall productivity.
Solution Approach 2:
The patent applies partial action by performing complete parasitic extraction analysis on only a subset of interconnect lines—specifically those that pass initial geometric filtering—rather than analyzing all lines exhaustively. This partial analysis approach maintains measurement precision for critical lines while significantly improving productivity by avoiding redundant analysis of lines that fail geometric criteria.
2Productivity
If geometric filtering is applied to exclude interconnect lines before parasitic extraction, then productivity is improved, but measurement precision may deteriorate due to potential false exclusions
Solution Approach 1:
The patent performs preliminary geometric analysis of interconnect lines before conducting parasitic extraction. This preliminary action involves calculating impedance estimates based on physical dimensions (length, width, material properties) and routing characteristics to pre-filter lines that definitely exceed maximum thresholds. This preliminary filtering improves productivity by eliminating obvious failures early, while the subsequent parasitic extraction on remaining lines ensures measurement precision is not compromised for critical cases.
Solution Approach 2:
The patent applies different analysis depths to different interconnect lines based on their geometric characteristics. Lines with dimensions and patterns that clearly indicate excessive impedance receive only geometric filtering, while lines with borderline or critical characteristics undergo full parasitic extraction analysis. This localized quality approach optimizes productivity by applying comprehensive analysis only where locally necessary, avoiding false exclusions while maintaining overall efficiency.
Data Source
AI summary
Techniques for efficiently determining whether an interconnect line has an impedance component value below a maximum specified value. A specified maximum impedance component value is used to limit the number of interconnect lines that are analyzed by a parasitic extraction analysis process. An analysis window is created based upon the characteristics of the interconnect lines and the specified maximum impedance component value. The size of the window corresponds to the minimum length of the interconnect line that would have the specified maximum impedance component value. Once the analysis window has been created, the interconnect lines are examined to determine if any of them reaches to or beyond the analysis window, whereby interconnect lines that exceed the specified maximum impedance component value can be identified. If there are any remaining interconnect lines that have not been determined to exceed the specified maximum impedance component value through the use of the analysis window, then the impedance component values of these remaining interconnect lines can be specifically determined using a parasitic extraction process.