Block Copolymer Lithography Dummy Pattern Aperture Control
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Solution Overview
Problem
Conventional lithography techniques face challenges in achieving desired microphase separation patterns due to issues with block copolymer embedding in regions of varying pattern density, leading to either flooding or insufficient embedding, resulting in inadequate film thickness and processing resistance.
Innovation Solution
A pattern forming method involving the creation of a physical guide with a first predetermined pattern and a dummy pattern on a lower layer film, where the block polymer is microphase-separated, and the second polymer section is selectively removed, using the first polymer section and the physical guide as a mask to transfer the desired hole pattern shape to the lower layer, while the dummy pattern adjusts the aperture ratio to prevent flooding and ensure appropriate embedding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If block copolymer coating is applied to achieve appropriate embedding in high pattern density regions, then embedding accuracy is improved, but block copolymer floods in low pattern density regions leading to failed microphase separation
Solution Approach 1:
The patent applies local quality by introducing dummy patterns specifically in low pattern density regions to create localized aperture ratio adjustment. This allows the block copolymer embedding conditions to be optimized locally in different regions - high density regions maintain their original embedding characteristics while low density regions receive additional dummy patterns to prevent flooding, thereby resolving the contradiction between embedding accuracy and microphase separation success across varying pattern densities
Solution Approach 2:
The patent employs partial or excessive action by adding dummy patterns in low pattern density regions where they are not strictly needed for pattern formation but are excessive enough to adjust the aperture ratio and prevent block copolymer flooding. This partial addition of structural elements compensates for the insufficient embedding in low density regions without affecting the overall pattern design
2Reliability
If block copolymer coating is applied to achieve appropriate embedding in low pattern density regions, then microphase separation is improved, but block copolymer is not sufficiently embedded in high pattern density regions leading to insufficient film thickness
Solution Approach 1:
The patent applies local quality by selectively placing dummy patterns only in low pattern density regions rather than uniformly across the entire substrate. This localized approach ensures that low density regions receive the necessary aperture ratio adjustment for proper microphase separation, while high density regions maintain their original embedding characteristics and achieve sufficient film thickness without unnecessary additions
3Manufacturing precision
If dummy pattern is added to adjust aperture ratio in low pattern density region, then block copolymer embedding is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the substrate into high pattern density regions and low pattern density regions, and applying different structural configurations to each segment. Dummy patterns are added only to the low density region segment, creating a segmented structure that optimizes block copolymer embedding where needed while maintaining simplicity in regions where it is not required, thereby managing device complexity effectively
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 method allows for the formation of microphase separation patterns with desired film thickness and shape, even in regions with differing pattern densities, by preventing block polymer flooding and ensuring sufficient embedding, thereby improving processing resistance and pattern transfer efficiency.
Implementation Method 1
making the block polymer microphase-separated to form a pattern having a first polymer section and a second polymer section
Implementation Method 2
the second polymer section is selectively removed by irradiation with oxygen plasma
Data Source
AI summary
According to one embodiment, a pattern forming method includes forming a physical guide that includes a first predetermined pattern in a first region on a lower layer film, and includes a second predetermined pattern and a dummy pattern in a second region on the lower layer film, forming a block polymer inside the physical guide, making the block polymer microphase-separated to form a pattern having a first polymer section and a second polymer section, removing the second polymer section to form a hole pattern, and processing the lower layer film after removal of the second polymer section, with the physical guide and the first polymer section used as a mask. Shapes of the hole patterns in the first and the second predetermined patterns are transferred to the lower layer film. A shape of the hole pattern in the dummy pattern is not transferred to the lower layer film.