L3GOlizer

L3GOlizer is a layout migration tool to convert traditional shape based layouts into the simplified layouts satisfying the restrictive design rules with multiple grid constraints.

Background
Design regularity is the trend.

• The variability of shape and physical properties gets worse
• Shape variation affects manufacturability and yield
• Post-layout OPC/RET becomes more costly
• Leading technology companies already embrace regularity
  -- Restrict gate polysilicon
• Restrictive design rules (L3GO) is proposed
  -- Simple geometric objects (points, sticks, rectangles)
  -- Multiple grid constraints
• Benefits of restricted designs
  -- Less variation and better manufacturability
  -- Improves designer productivity by removing much of the details in managing technology churn from the circuit designer’s set of responsibilities.
  -- Implements a reduced set of tech rules that improve yield for a small cost in area
  -- Improves the efficiency of downstream post-layout processing

The problems demand novel solutions.

• Existing methods to convert a polygon shape to wire sticks are not effective
• L3GO legalization has multiple grid constraints, which is not addressed in the literature

Overview
L3GOlizer consists of two steps:

• Conversion: converting shapes to simple geometric objects. A new concept, rectilinear medial axis, is proposed, and an algorithm is developed to create the rectilinear medial axis for representing the sticks in the conversion.
• Legalization: putting objects on grid and satisfying design rules. A novel graph-based algorithm is proposed to handle the multiple grid constraints efficiently.

Publications
1. X. Tang and X. Yuan, "Technology Migration Techniques for Simplified Layouts with Restrictive Design Rules", 2006 International Conference on Computer Aided Design (ICCAD), San Jose, CA, 2006.

Last updated August 15, 2007