IC Routing via Enhanced Topologies and Guides
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Solution Overview
Problem
Conventional IC design routing methods face challenges in maintaining ideal routing paths for timing-critical nets due to design-rule constraints, leading to degradations in timing, skew, and slew during detailed routing, especially when these paths cross blockages or congestion areas.
Innovation Solution
The introduction of enhanced routing topologies using routing guides to reroute paths within these constraints, combined with a source-to-sink-aware bounding box expansion method, allows for resolving design-rule constraints while minimizing changes to the initial routing topology, thus reducing further degradation in timing and slew.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional routing methods are used to connect pins in IC design, then routing can be completed, but timing degradation and slew degradation occur due to design-rule constraints forcing deviations from ideal routing paths
Solution Approach 1:
The patent applies preliminary action by performing global routing first to establish ideal routing paths before detailed routing. The global router determines approximate routing paths that optimize timing and performance, and then the detailed router follows these pre-established paths while satisfying design-rule constraints. This two-phase approach ensures that timing-critical nets maintain their ideal paths rather than being forced to deviate due to constraint compliance during routing.
Solution Approach 2:
The patent segments the routing process into two distinct phases: global routing and detailed routing. Global routing handles high-level path determination with focus on timing optimization, while detailed routing handles local constraint satisfaction. This segmentation allows each phase to specialize in its strength without compromising the other, resolving the contradiction between timing performance and constraint compliance.
2Ease of manufacture
If routing paths are modified to satisfy design-rule constraints, then constraint compliance is achieved, but timing and slew degradations increase
Solution Approach 1:
The patent establishes routing paths in advance during global routing before detailed routing begins. These pre-determined paths are optimized for timing performance and serve as guides for the detailed router. By performing the path-planning action preliminarily, the system ensures timing optimization is locked in before constraint-satisfaction actions are taken during detailed routing.
Solution Approach 2:
The patent applies local quality by allowing different routing strategies for different regions. Timing-critical nets maintain their ideal global routing paths with minimal deviation, while non-critical nets can accommodate more constraint-based modifications. This localized approach ensures that design-rule compliance does not uniformly degrade timing performance across all nets.
3Productivity
If detailed routing follows ideal routing paths without enhancement, then routing speed is maintained, but design-rule constraints cannot be satisfied in congestion areas
Solution Approach 1:
The patent performs preliminary global routing to establish approximate paths that account for potential congestion areas. This preliminary action provides the detailed router with pre-planned alternatives, enabling it to satisfy design-rule constraints in congestion areas without significant deviation from ideal paths, thus maintaining both efficiency and compliance.
4Loss of time
If conventional global routing generates approximate routing paths, then routing topology is established quickly, but timing-critical net paths may cross blockages or congestion areas causing performance degradation
Solution Approach 1:
The patent applies preliminary action by performing global routing with timing-aware algorithms that identify and protect timing-critical net paths during the initial topology establishment. This preliminary timing optimization ensures that even approximate paths do not cross blockages or congestion areas, preventing performance degradation before detailed routing begins.
Data Source
AI summary
Aspects of the present disclosure address improved systems and methods for routing based on enhanced routing topologies. Consistent with some embodiments, the method may include accessing a routing topology of an integrated circuit design and determining that a routing path of a net in the routing topology violates a routing constraint. In response to determining that the routing path violates the routing constraint, a routing guide is created to reroute the routing path. The routing path in the net is then rerouted using the routing guide, thereby producing an enhanced routing topology that reduces issues in detailed routing caused by the routing constraint violation.