Timing Driven Routing for Integrated Circuit Design
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Solution Overview
Problem
Current IC design routing processes often deteriorate the timing characteristics of optimized designs, as existing routers are not aware of the criticality of nets, leading to significant deterioration in timing and overall design merit.
Innovation Solution
A method for timing-driven routing that includes pre-global routing optimization, setting wirelength target constraints, prioritizing nets, and performing detailed routing to maintain timing optimization and minimize wirelengths, thereby addressing the criticality of nets during the routing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional routing processes are used, then routing completion is achieved, but timing characteristics deteriorate significantly
Solution Approach 1:
The patent applies preliminary action by performing pre-global routing optimization to calculate target wirelength constraints for each net before the actual routing process. This advance preparation allows the router to prioritize timing-critical nets and make informed routing decisions, preventing timing deterioration while maintaining routing efficiency.
Solution Approach 2:
The patent changes parameters by introducing wirelength target constraints and net priority values as new routing parameters. The router uses these parameters to adjust its routing behavior, selecting paths that meet timing requirements rather than simply minimizing wirelength or avoiding congestion, thus resolving the contradiction between timing quality and routing efficiency.
2Manufacturing precision
If wirelength is minimized during routing, then routing quality improves, but timing optimization deteriorates
Solution Approach 1:
The patent applies local quality by treating different nets differently based on their timing criticality. Instead of applying a uniform wirelength minimization strategy to all nets, the router uses pre-calculated target wirelength constraints and priority values to apply localized routing strategies. Timing-critical nets receive specialized attention with constrained wirelength targets, while non-critical nets allow more flexibility, thus maintaining both wirelength control and timing optimization.
3Productivity
If detailed routing is performed without net prioritization, then routing completeness is achieved, but timing characteristics worsen
Solution Approach 1:
The patent performs preliminary action by assigning priority values to nets based on their timing criticality before the detailed routing process. This prioritization information guides the router to handle timing-critical nets first or with special consideration during detailed routing, ensuring that routing completion is achieved while preserving timing characteristics through informed decision-making at each routing step.
Data Source
AI summary
A method, system, and computer program product for timing driven routing in a design of an integrated circuit (IC) are provided in the illustrative embodiments. A router application executing in a data processing system performs a pre-global routing optimization of the design. A plurality of wirelength target constraints are set on a plurality of subsets of a set of nets in the design. Global routing is performed on the design. The design is adjusted using wires placed in the design during the global routing. A priority is assigned to each net in the set of nets. Detailed routing is performed on the design.