DSA-Aware Layout Decomposition for Sub-22nm Lithography
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Solution Overview
Problem
Conventional lithographic techniques face challenges in achieving long-range order and reducing manufacturing costs for sub-22 nm node integrated circuits, as multiple patterning methods are costly and inefficient, especially when combined with directed self-assembly (DSA) techniques.
Innovation Solution
A method involving the generation of a coloring/grouping graph from layout data to optimize the assignment of layout features to masks, allowing for parallel combination of DSA and multiple patterning lithography, which includes grouping layout features and generating guiding patterns to address DSA constraints and reduce coloring violations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple patterning techniques are used to achieve further lithography scaling, then resolution is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent combines multiple patterning lithography and directed self-assembly (DSA) into a hybrid process flow. The DSA step is inserted between patterning steps to form features that would otherwise require additional lithography masks, thereby reducing total mask count and manufacturing cost while maintaining the required resolution for sub-22 nm nodes
Solution Approach 2:
The patent introduces DSA as an intermediary process between conventional lithography steps. The block copolymer self-assembly acts as a mediator that transforms lithographically-defined guiding patterns into the final fine-pitch patterns, enabling cost-effective resolution enhancement without directly increasing lithography complexity
2Manufacturing precision
If conventional multiple patterning is used, then resolution scaling is achieved, but the number of patterning steps increases
Solution Approach 1:
The patent merges the functions of multiple lithography patterning steps with a single DSA process. By using DSA to form features that would otherwise require separate lithography masks, the total number of patterning steps is reduced while maintaining the required resolution for advanced technology nodes
3Ease of manufacture
If DSA is used for contact and via layers, then total mask count is reduced, but layout decomposition complexity increases
Solution Approach 1:
The patent segments the layout decomposition process into distinct phases: initial decomposition for multiple patterning, identification of DSA candidate features, and secondary decomposition adjustments. This segmentation allows the complex DSA-aware decomposition to be managed systematically, reducing the overall complexity while enabling mask count reduction through DSA
Solution Approach 2:
The patent performs preliminary layout decomposition for multiple patterning before applying DSA-specific optimizations. By establishing the base decomposition first and then iteratively adjusting for DSA opportunities, the method manages complexity by breaking down the problem into manageable stages rather than attempting to solve all constraints simultaneously
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces manufacturing costs by potentially replacing traditional quadruple patterning with a triple patterning process, maintaining yield and improving the uniformity and precision of pattern formation, thereby enhancing the efficiency of lithographic processes.
Implementation Method 1
In self-assembly, the formation of features of fine geometric dimensions occurs not through external patterning, but through the spontaneous phase behavior found among polymers on the molecular level
Implementation Method 2
chemically patterning a surface to create local affinities to the various portions of the block co-polymers (chemo-epitaxy)
Data Source
AI summary
Aspects of the disclosed technology relate to techniques of combining directed self-assembly lithography and multiple patterning lithography. A coloring/grouping graph is first generated from layout data of a layout design. In the coloring/grouping graph, each coloring edge connects two nodes representing layout features that must be assigned to different masks, and each grouping/coloring edge connects two nodes representing layout features that should either be grouped together for DSA (directed-self-assembly) lithography or be assigned to different masks for multiple patterning lithography. The node groups formed by nodes connected with the coloring edges are colored. Colors of the nodes in one or more of node groups connected by the grouping/coloring edges are adjusted to convert one or more of the grouping/coloring edges into the coloring edges. After conversion, layout features represented by the nodes directly connected with the grouping/coloring edges are grouped together for generating guiding patterns.