Multi-Patterning Lithography Coloring Conflict Resolution
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Solution Overview
Problem
In advanced semiconductor fabrication, multi-patterning lithography (MPL) faces challenges in assigning circuit patterns to masks without violating the minimum separation distance rule, leading to uncolorable circuit patterns and coloring conflicts, which limits the resolution of photoresist performance beyond the 22-nm node.
Innovation Solution
A cell-based layout refinement scheme is proposed to identify and group uncolorable cells, performing local and global refinement operations to reduce the number of uncolorable cells by adjusting cell positions through movements like flipping, shifting, and swapping, while ensuring no new coloring conflicts are introduced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-patterning lithography is used to shrink feature pitch, then manufacturing precision is improved, but coloring conflicts and uncolorable cells increase
Solution Approach 1:
The layout is divided into individual cells that can be independently analyzed and processed. Each cell is evaluated for colorability separately, and uncolorable cells are identified and handled through specific refinement operations. This segmentation allows the complex global coloring problem to be broken down into manageable local problems.
Solution Approach 2:
The patent implements dynamic refinement operations that adjust cell positions through movements like flipping, shifting, and swapping. These operations are applied iteratively to transform uncolorable cells into colorable ones, dynamically adapting the layout to resolve coloring conflicts while maintaining manufacturing precision.
2Device complexity
If layout refinement operations are performed to resolve coloring conflicts, then coloring conflicts are reduced, but computational burden increases
Solution Approach 1:
The computational problem is segmented by identifying and processing only uncolorable cells rather than the entire layout. Local refinement operations are applied specifically to uncolorable cell groups, significantly reducing the computational scope compared to global optimization approaches.
Solution Approach 2:
Different refinement strategies are applied locally based on the specific characteristics of uncolorable cells. The patent uses targeted movements (flipping, shifting, swapping) appropriate for each cell's context, rather than applying uniform global operations, which optimizes computational efficiency while resolving conflicts.
3Manufacturing precision
If cell positions are adjusted to eliminate uncolorable cells, then manufacturing precision is maintained, but layout complexity increases
Solution Approach 1:
The patent applies preliminary actions by identifying uncolorable cells before final mask assignment and performing refinement operations in advance. This prevents coloring conflicts from propagating through the design process and eliminates the need for later corrective actions that would increase layout complexity.
Solution Approach 2:
The refinement operations are self-contained within uncolorable cell groups, using only the cells within each group to resolve their own coloring conflicts. This self-service approach avoids introducing dependencies on other parts of the layout, preventing increases in overall layout complexity.
Data Source
AI summary
A method performed by at least one processor includes: accessing a layout of an integrated circuit (IC), where the layout includes a plurality of patterns in one or more layers of the layout; performing a coloring operation; forming a list comprising at least one uncolorable cell group (UCG) of the layout based on a result of the coloring operation, where each of the at least one UCG comprises at least one uncolorable cell; and performing a first refinement for each UCG on the list. The first refinement is performed through: performing a movement on at least one uncolorable cell of the UCG; determining whether the UCG is colorable; and refining the layout by accepting the movement and removing the UCG from the list in response to the UCG being determined to be colorable.