Analog Layout Migration Using Constraint Hierarchy Tree
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Solution Overview
Problem
Current analog layout migration methods are time-consuming and require manual intervention, as they do not efficiently generate optimized layouts for new technologies while preserving circuit performance and adhering to constraints such as symmetry and design rules.
Innovation Solution
A method that constructs a constraint hierarchy tree from the original layout, allowing for the generation of multiple placements based on new technology constraints, using a bottom-to-top process and cost-function evaluation to optimize wire length and area, while maintaining similar circuit performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual redrawing of layouts is used for analog design migration, then circuit performance can be maintained, but design time becomes very long and the process is tedious
Solution Approach 1:
The patent uses the existing layout as a template or symbolic structural model that preserves topology, symmetry, and matching information. Instead of manually redrawing, the system copies the structural relationships from the original layout and applies them to new device sizes through automated algorithms, maintaining circuit performance while eliminating tedious manual work
Solution Approach 2:
The patent changes device parameters (width, length, finger number) while preserving layout topology. By parameterizing devices and using hierarchical relationships, the system automatically adjusts layouts for new process technologies without requiring manual redrawing, thus reducing design time while maintaining performance
2Area of stationary object
If layout compaction algorithms are used for migration, then layout area is minimized, but the process becomes very time-consuming for complicated layouts
Solution Approach 1:
The patent segments the layout into hierarchical groups of device modules, organizing them in a tree structure. This segmentation allows the algorithm to process smaller sub-groups independently and combine results, reducing the overall complexity and computation time compared to processing the entire layout at once, while still achieving area optimization
Solution Approach 2:
The patent performs preliminary analysis of the original layout to extract topology, symmetry, and matching constraints before optimization. By pre-processing and storing this structural information, the algorithm avoids redundant computations during the optimization phase, significantly reducing migration time for complicated layouts
3Productivity
If automated layout migration is implemented, then design time is reduced, but flexibility for designer modifications is limited
Solution Approach 1:
The patent implements a dynamic constraint hierarchy system where constraints can be selectively applied or modified based on designer requirements. The hierarchical structure allows designers to adjust constraints at different levels (individual devices, device groups, or entire layout) and re-run optimization, providing flexibility while maintaining automated efficiency
Solution Approach 2:
The system provides feedback mechanisms that allow designers to review automated migration results and identify areas for modification. The hierarchical constraint structure enables selective re-optimization of specific regions or devices, allowing iterative refinement while maintaining the benefits of automated migration
Data Source
AI summary
A computer implemented method for forming an integrated circuit (IC) layout is presented. The method includes forming a constraint tree when a computer is invoked to receive a first layout of the IC and generating a second layout of the IC in accordance with the constraint tree.