Imprint Template Alignment Marks Embedded in Mesa Portion
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Solution Overview
Problem
In nanoimprint lithography, alignment marks on imprint templates with concave and convex patterns can transfer defects into the resist layer, affecting subsequent processes and integration density in semiconductor fabrication.
Innovation Solution
An imprint template structure with alignment marks embedded in a mesa portion, having a light transmittance lower than the mesa portion, and field patterns defined by concave and convex surface profiles, which are not imprinted into the resist layer, allowing precise alignment without introducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alignment marks with concave and convex patterns are used on the imprint template, then alignment precision is improved, but defects are transferred into the resist layer causing process failures
Solution Approach 1:
The imprint template is divided into two distinct regions: a first region containing alignment marks with concave and convex patterns for precise alignment, and a second region containing field patterns with concave and convex patterns for pattern transfer. This segmentation allows the alignment marks to maintain their beneficial patterning for alignment while preventing defect transfer to the resist layer, as the alignment marks are in a separate region that does not directly imprint onto the resist.
Solution Approach 2:
The harmful effect of defect transfer is eliminated by extracting the alignment mark function from the field pattern region. The alignment marks are placed in a dedicated first region that is structurally separated from the second region where field patterns are imprinted. This extraction allows alignment marks to provide precise alignment without their patterns being transferred into the resist layer as defects.
2Measurement precision
If assist patterns are transferred into the resist layer to assist alignment, then alignment capability is improved, but the transferred patterns act as defects affecting subsequent processes
Solution Approach 1:
The template is segmented into a first region for alignment marks and a second region for field patterns. The alignment marks in the first region provide the necessary alignment capability through their concave and convex patterns, while the second region contains only the field patterns needed for pattern transfer. This segmentation ensures that assist patterns do not get transferred into the resist layer as defects, resolving the contradiction between alignment capability and defect generation.
3Productivity
If the imprint template contacts the resist layer to transfer field patterns, then pattern transfer efficiency is improved, but alignment marks and assist patterns are also transferred causing contamination
Solution Approach 1:
The imprint template is divided into a first region containing alignment marks and a second region containing field patterns. During the imprinting process, only the field patterns in the second region are transferred into the resist layer with high efficiency, while the alignment marks in the first region remain on the template surface and are not transferred. This segmentation maintains high pattern transfer efficiency while preventing contamination from alignment marks and assist patterns.
Solution Approach 2:
The harmful transfer of alignment marks and assist patterns into the resist layer is prevented by extracting these elements into a separate first region that does not contact or transfer to the resist layer. The field patterns in the second region maintain direct contact with the resist layer for efficient pattern transfer, while the aligned marks are taken out of the transfer path, eliminating contamination while preserving productivity.
Data Source
AI summary
There is provided a method of performing a nanoimprint lithography process. The method includes providing an imprint template having field patterns and an alignment mark. The field patterns are defined by a concave and convex surface profile of each of field regions of the imprint template, and the alignment mark is embedded in a boundary region of the imprint template. A resist layer is formed on a substrate having a reference alignment mark. The field patterns are imprinted on the resist layer to embed the field patterns into the resist layer while the imprint template is aligned with the substrate using the alignment mark and the reference alignment mark. Related imprint template structures are also provided.