Flexible Self-aligned Double Patterning
Aware Detailed
Routing with Prescribed Layout Planning
Jhih-Rong Gao and David Z. Pan
ECE Dept. Univ. of Texas at Austin, Austin
ISPD 2012
Outline
• Introduction
• Preliminaries
• Algorithm
• Experimental results
• Conclusion
Introduction
• DPL
- LELE (litho-etch-litho-etch)
- SADP (self-aligned double patterning)
• LELE
- allow stitch insertion to resolve conflict
- much more overlay error than SADP
• SADP
- core mask and trim mask
- good overlay controllability
- no stitch allowed
Preliminaries
• we propose a robust multi-layer SADP-aware detailed routing
algorithm.
• Our approach adopts the grid-based routing model.
• We define the minimum width of mandrel pattern and trim
pattern as Wmin.
• We also assume that the width of sidewall spacer equals to
Wmin.
• A minimum spacing Smin must be kept between any
neighboring routing patterns.
• For a legal layout decomposition result, patterns within the
minimum DPL spacing Sdp must be assigned to different types
of pattern (mandrel pattern or trim pattern).
Algorithm
• SADP-aware routing guidelines
• Simultaneous layer assignment for conflict prevention
• Overall flow
• SADP-aware weighted cost
• Neighborhood-based net ordering
This ordering method encourages nets within a certain
distance to be routed in a sequence, so that the probability to
provide spacer protection for these neighboring nets can be
increased.
Experimental results
Conclusion
• A novel multi-layer SADP-aware detailed routing approach.
• Solve routing and layout decomposition simultaneously based
on the correct-by-construction approach.
• Incorporate layer assignment to resolve potential pattern
conflicts, which increases the flexibility of layout
decomposition for SADP.
• Present a set of SADP-aware routing guidelines, which helps
improve the pattern quality of SADP.