Standard Cell Placement Edge Labeling for Double Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In integrated circuit (IC) design, standard cell placement using double patterning technology often results in illegal color assignments due to minimum spacing limitations, leading to un-colorable configurations, which complicates the placement process and requires numerous iterations to achieve a colorable layout.
Innovation Solution
A method involving edge labeling of standard cells with {ZERO, SINGLE, DOUBLE} labels, based on the proximity of objects to the edges, and a truth table to determine legal spacing between cells, allowing for efficient generation of colorable placements, reducing the need for extensive iterations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If double patterning technology is used to increase pattern density, then object density is doubled, but illegal color assignments and un-colorable configurations occur due to minimum spacing limitations
Solution Approach 1:
The patent applies preliminary action by performing edge labeling on standard cells before the actual placement process. Each edge is pre-classified as ZERO, SINGLE, or DOUBLE based on the colors of objects within distance λ. This pre-characterization enables the placement algorithm to make informed decisions about cell spacing from the outset, preventing illegal color assignments rather than detecting and correcting them after placement attempts.
Solution Approach 2:
The patent changes the parameter representation by introducing edge labels that encode color information. Instead of working directly with complex color assignment constraints during placement, the method transforms the problem into working with simplified edge labels (ZERO, SINGLE, DOUBLE) that capture the essential spacing requirements. This parameter transformation makes the placement process more tractable while ensuring color assignment legality.
2Manufacturing precision
If extensive iterations are performed to achieve colorable placement, then legal spacing is ensured, but computing resources and time are significantly consumed
Solution Approach 1:
By pre-labeling edges with color information before placement, the patent eliminates the need for repeated color assignment checks and iterative adjustments during the placement process. The edge labels provide immediate guidance on required spacing, allowing the placement algorithm to generate legal placements directly without extensive iterations.
Solution Approach 2:
The edge labels serve as an intermediary that mediates between the complex color assignment constraints and the placement algorithm. Instead of directly handling intricate color compatibility checks, the algorithm works with the simplified edge label representations, which encode all necessary spacing information in a readily usable format.
3Manufacturing precision
If minimum spacing constraints are enforced for same-color objects, then lithographic resolution is maintained, but placement flexibility is reduced
Solution Approach 1:
The patent applies local quality by differentiating edge labels based on the specific color composition at each edge. ZERO edges (no objects within λ) allow maximum flexibility, SINGLE edges (one color) provide moderate constraints, and DOUBLE edges (two colors) impose the strictest spacing requirements. This localized characterization of edges enables the placement algorithm to optimize spacing decisions for each specific context while maintaining lithographic resolution.
Data Source
AI summary
A method for generating legal colorable multiple patterning standard cell placement is provided. In this method, a standard cell library including color information can be accessed. For each standard cell, edge labels can be assigned based on colors of objects within a predetermined distance from each edge. A truth table, which indicates legal spacing between pairs of standard cells based on their edge labels, can be accessed. A plurality of standard cells of a design can then be placed based on the truth table.