An Extended Study of Gear-Ratio-Aware Standard Cell Layout Generation for DTCO Exploration

2026-03-13

AI Summary

This work addresses the challenge posed by the decoupling of contacted poly pitch (CPP) and bottom-metal pitch in advanced process nodes, which necessitates standard cell layouts that support arbitrary gear ratios (GR) and offset parameters to co-optimize routing and performance. To this end, the authors propose CPCell, a framework that jointly optimizes placement and routing through fine-grained hierarchical grid graph modeling and constraint programming. CPCell incorporates Middle-of-Line routing, M0 pin enabling, pin accessibility constraints, and weighted multi-objective optimization. Acceleration techniques—including transistor clustering, tightened routing lower bounds, and early termination—enable efficient handling of cells with up to 48 transistors. Experimental results demonstrate significant improvements in combined power, performance, area, and IR drop metrics across diverse GR and offset configurations.

Technology Category

• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Planning, Routing, and Scheduling: Mixed Discrete/Continuous Planning
• Machine Learning: Hardware-aware ML

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Security and Privacy: Large-scale security measurements
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

Advanced nodes decouple contacted poly pitch (CPP) and lower-metal pitch to improve routability. We present CPCell, an efficient standard-cell layout generation framework, to support arbitrary gear ratio (GR) and offset parameters through a fine-grained layered grid graph and constraint-programming-based placement-routing co-optimization. Layout quality is improved via Middle-of-Line routing, M0 pin enablement, pin accessibility constraints and a weighted multi-objective formulation that jointly optimizes cell layouts. To scale to netlists with up to 48 transistors, we incorporate acceleration techniques including transistor clustering, identical transistor partitioning, routing lower bound tightening and early termination strategies. Comprehensive cell-level and block-level studies are conducted to evaluate GR and offset choices, quantify the benefits of the proposed objectives and assess their impact on power, performance, area and IR-drop outcomes.

Problem

• standard cell layout
• gear ratio
• DTCO
• placement-routing co-optimization
• advanced nodes

Innovation

• gear ratio
• standard cell layout
• constraint programming
• placement-routing co-optimization
• DTCO