Optimally Minimizing Overlay Violation in Self-aligned
Double Patterning Decomposition for Row-based
Standard Cell Layout in Polynomial Time
Z. Xiao, Y. Du, H. Tian, M. D.F. Wong
Department of ECE
University of Illinois at Urbana-Champaign
ICCAD 2013
Outline
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Introduction
Preliminaries
SADP Decomposition Algorithm for Row-based
Standard Cell Layout
Experiments
Conclusion
Introduction
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Self-aligned double patterning (SADP) is one of the
most promising double patterning techniques for
sub-20nm nodes.
Introduction
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This paper focus on SADP decomposition problem
for row-based standard cell layout.
The objective is to minimize the total number of
overlay violations.
Preliminaries
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Overlay Violation
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The critical sides that are not protected by sidewalls.
Consider the line ends of the feature as non-critical, while
the sides are critical.
Preliminaries
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SADP Decomposition in Row-based Standard Cell
Layout
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The standard cells in a library have the same height but may
have different width.
Multiple rows are stacked vertically to complete a row-based
standard cell layout.
Standard Cell
A standard cell row
Preliminaries
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Problem Definition
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Given a row-based standard cell layout with
fixed height.
Our objective is to decompose the layout into a
set of core patterns and block patterns for SADP
patterning.
The number of overlay violations is minimized.
Preliminaries
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SADP Mask Rules
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The minimum width of a core (block) pattern is d
The minimum distance between two adjacent
patterns is s
The width of sidewalls is w
SADP Decomposition
Algorithm
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Two methods to generate a feature:
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Use a core pattern that has an exact same shape as the
feature.
An auxiliary core pattern is placed along the feature sides,
such that the sidewalls generated define the feature.
SADP Decomposition
Algorithm
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Finding decomposition from an assigment
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Merge a pair of conflicting features when they
are both assigned as cores.
Core-core-merge (CCM)
SADP Decomposition
Algorithm
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Finding decomposition from an assigment
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Feature B is assigned as core and merges with
the auxiliary core of A.
Core-aux-merge (CAM)
SADP Decomposition
Algorithm
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Finding decomposition from an assigment
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Removal of the conflicting part of auxiliary core.
Merging conflicting main core and auxiliary core.
Core-aux-removal (CAR)
Core-aux-merge (CAM)
SADP Decomposition
Algorithm
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Finding decomposition from an assigment
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Two auxiliary cores can be merged together
directly.
Aux-aux-merge (AAM)
An Example
An Example
An Example
Experiments
Conclusion
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This paper discussed the SADP decomposition for
row-based standard cell layout.
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Experimental results with industrial level standard
cells showed that the proposed method can solve
large scale problems in a relatively short time.