Imprint Lithography Template Zero-Gap Field Borders
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Solution Overview
Problem
In nano-fabrication processes like imprint lithography, large pattern exclusion zones or gaps between adjacent fields on semiconductor wafers lead to issues during downstream processing, causing non-uniformity and exposure of the substrate to etching agents, which can result in defects and processing problems.
Innovation Solution
The implementation of a template with leading and trailing edge borders featuring dummy patterns and chamfered corners allows for zero-gap imprinting, ensuring full-feature height patterns at field borders and preventing fluid extrusion, thereby eliminating gaps between imprinted fields and maintaining uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional imprint lithography is used with pattern exclusion zones between fields, then the imprinting process is simpler, but gaps between adjacent fields cause non-uniformity and expose substrate to etching agents during downstream processing
Solution Approach 1:
The patent applies preliminary action by adding dummy patterns to the template design before the actual imprinting process. These dummy patterns are pre-configured at the field borders to create full-feature-height structures that prevent gap formation between adjacent fields during downstream processing, thereby proactively solving the uniformity issue before it occurs
Solution Approach 2:
The patent applies local quality by modifying only the border regions of the template with dummy patterns and chamfered corners, while leaving the central patterned areas unchanged. This localized modification approach maintains the overall simplicity of the template structure while specifically addressing the gap formation problem at field boundaries
2Manufacturing precision
If zero-gap imprinting is implemented with dummy patterns and chamfered corners, then gaps between fields are eliminated and uniformity is maintained, but the template design becomes more complex
Solution Approach 1:
The dummy patterns are designed into the template in advance at the field borders, creating full-feature-height structures that will prevent gap formation during subsequent processing steps. This preliminary configuration ensures zero-gap imprinting without requiring complex real-time adjustments
Solution Approach 2:
The chamfered corners introduce asymmetric geometry to the template design, where the corners are beveled at specific angles (e.g., 45 degrees) rather than being square. This asymmetric feature helps prevent gap formation at the corners of adjacent fields while maintaining overall design simplicity
3Reliability
If dummy patterns are added to confine imprint fluid, then fluid extrusion is prevented and processing uniformity is maintained, but the template requires additional features
Solution Approach 1:
The dummy patterns are localized exclusively to the field border regions where fluid extrusion and gap formation occur. The central patterned areas remain unchanged, so the additional features are confined to specific locations rather than遍布 the entire template, minimizing the overall impact on template complexity
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 enables seamless abutment of adjacent fields without gaps, maintaining uniformity and preventing defects by using dummy features to confine the imprint fluid and accommodate variations in fluid volume, ensuring consistent processing across the wafer.
Implementation Method 1
The formable liquid is solidified to form a rigid layer that has a pattern conforming to a shape of the surface of the template that contacts the formable liquid
Data Source
AI summary
Imprint lithography templates having leading and trailing edge borders are provided that achieve zero-gap imprinting between adjacent fields with full-feature height features provided in the pattern exclusion zones (PEZ) located between such fields. The leading edge borders include dummy features, e.g., elongated features directionally oriented parallel to the mesa edge, while the trailing edge border includes a recess extending to the mesa edges. When used in a step-and-repeat process, the trailing edge border overlaps edge portions of an adjacent imprinted field that were previously patterned by the leading edge border of the template, producing full-feature height features in the pattern exclusion zones between such fields, and avoiding gaps or open areas between such fields that otherwise lead to non-uniformity of downstream processes such as etch processes and CMP.