Timing Closure in Chip Design via Critical Path Variation Analysis

The patent applies preliminary action by identifying and analyzing critical timing paths before final chip design completion. The method performs timing analysis at multiple stages (post-synthesis, post-layout, post-extraction) to detect potential timing violations early, allowing designers to make adjustments before the design is finalized and sent to manufacturing. This proactive approach prevents timing closure failures that would occur with reduced timing windows.

The patent segments the timing analysis process into distinct phases: synthesis stage timing analysis, layout stage timing analysis, and post-extraction timing analysis. Each phase focuses on specific aspects of the design and uses appropriate timing models for that stage. This segmentation allows for more precise timing analysis at each level, improving overall timing accuracy even when the total timing window is reduced.

The patent incorporates wire and device delay considerations at preliminary stages of the design process. By performing timing analysis post-synthesis and post-layout with increasingly accurate delay models, the method ensures that timing constraints are met before design completion. This approach maintains design process simplicity while improving timing closure reliability through progressive refinement of delay information.

The patent changes the parameters used for delay calculation at different design stages. Initially, simplified delay models are used during synthesis, then more accurate models incorporating actual wire lengths and device characteristics are applied post-layout and post-extraction. This progressive parameter refinement allows the design process to remain manageable while achieving accurate timing analysis for timing closure.

The patent segments the timing analysis into multiple stages with increasing accuracy, specifically addressing the challenges of advanced manufacturing processes. By separating synthesis-stage analysis from post-layout and post-extraction analysis, the method can use appropriate delay models for each stage, accurately capturing wire and device delay effects that become predominant in advanced processes like 32nm and 45nm.

The patent implements feedback mechanisms where timing analysis results from each stage inform subsequent design decisions. Post-layout timing analysis feeds back to guide layout modifications, and post-extraction timing analysis feeds back to confirm timing closure. This iterative feedback process ensures that timing violations are identified and corrected, maintaining timing closure reliability even as chip performance is enhanced through advanced manufacturing processes.