Nanoimprint Mold Substrate Thickness Control
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Solution Overview
Problem
In nanoimprint lithography, maintaining parallelism and uniform pressure between a mold and a recipient substrate is challenging due to the larger size of mold-forming substrates compared to the pattern formation area, leading to potential misalignment and pattern errors as feature sizes become finer and more complex.
Innovation Solution
A circular nanoimprint mold-forming substrate with a thickness variation of up to 0.6 µm within a 125 mm diameter circle, where the thickness at the thickest point is greater than or equal to the center thickness, and the thickness at the periphery is less than the center thickness, ensuring uniform pressure and reducing misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the outer shape of the mold-forming substrate is made larger to accommodate traditional lithography equipment, then ease of manufacture is improved, but manufacturing precision deteriorates due to increased difficulty in maintaining parallelism and uniform pressure
Solution Approach 1:
The substrate is divided into two functional zones: a large outer shape for ease of handling and equipment compatibility, and a central pattern formation region with controlled thickness variation. This segmentation allows the outer dimensions to be large while the critical central region maintains precision through specific thickness control (0.6 µm or less variation).
Solution Approach 2:
Different regions of the substrate are given different thickness characteristics. The central region where patterns are formed has tightly controlled thickness variation (0.6 µm or less), while the outer region can have greater variation. This local quality differentiation ensures high precision where needed without compromising overall manufacturability.
2Manufacturing precision
If the area where the pattern is formed is made smaller to increase accuracy, then manufacturing precision is improved, but device complexity increases due to the need for precise thickness control
Solution Approach 1:
The thickness parameter is changed across different regions of the substrate. The central region has a thickness variation of 0.6 µm or less, while the outer region has greater variation. This parameter change allows the central region to achieve high precision for pattern formation without requiring the entire substrate to meet stringent precision requirements, thereby reducing overall device complexity.
3Manufacturing precision
If the thickness variation of the substrate is reduced to maintain parallelism, then manufacturing precision is improved, but ease of manufacture deteriorates due to increased difficulty in achieving uniform thickness
Solution Approach 1:
The substrate exhibits different thickness characteristics in different regions. The central region where patterns are formed has controlled thickness variation (0.6 µm or less) to ensure precision, while the outer region can have greater variation making manufacturing easier. This local quality differentiation resolves the contradiction by applying high precision only where necessary.
Solution Approach 2:
The substrate is segmented into a central pattern formation region and an outer region. The central region has tightly controlled thickness for precision, while the outer region has greater thickness variation that is easier to manufacture. This segmentation allows simultaneous achievement of high precision in the critical area and ease of manufacture overall.
Data Source
Figure 1A~1B
Figure 2A~2C
AI summary
A circular mold-forming substrate of 125-300 mm diameter having a surface on which a topological pattern is to be formed is provided wherein the thickness of the substrate has a variation of up to 2 µm within a circle having a diameter of 125 mm.