Imprint Exposure Control for Partial Shot Pattern Uniformity
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Solution Overview
Problem
The imprint process in microfabrication techniques faces issues such as residual bubbles leading to pattern defects, substrate warping causing incomplete contact of imprint material with the mold, and variations in pattern dimensions due to oxygen inhibition or uncured material transfer, especially in the outer peripheral regions of the substrate.
Innovation Solution
An imprint apparatus that controls gas supply and light irradiation levels separately for full and partial shot regions, reducing gas supply and increasing light irradiation in partial shot regions to minimize defects and pattern dimension variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas supply is increased to suppress residual bubbles in the imprint process, then bubble suppression is improved, but uncured imprint material adhering to the mold in partial shot regions causes defects due to oxygen inhibition
Solution Approach 1:
The patent applies different gas supply amounts to different shot regions: a first gas supply amount is supplied to the full shot region, while a second gas supply amount (different from the first) is supplied to the partial shot region. This local differentiation resolves the contradiction by optimizing bubble suppression in the full shot region while preventing oxygen inhibition issues in the partial shot region.
2Reliability
If the imprint process is performed in an atmosphere with sufficient oxygen to prevent uncured material transfer, then defect reduction is improved, but pattern dimension variation increases due to oxygen inhibition of curing
Solution Approach 1:
The patent creates different oxygen environments in different shot regions by controlling gas supply: the full shot region receives a first gas supply amount that maintains oxygen presence to prevent uncured material transfer, while the partial shot region receives a second gas supply amount that optimizes curing. This local environmental control resolves the contradiction between defect reduction and pattern dimension uniformity.
3Device complexity
If uniform gas supply is used across all shot regions, then process simplicity is maintained, but pattern defects occur in partial shot regions due to substrate warping and incomplete contact
Solution Approach 1:
The patent implements differentiated gas supply control: a first gas supply amount for the full shot region and a second gas supply amount for the partial shot region. This accounts for the different conditions in partial shot regions (substrate warping, incomplete contact) while maintaining a relatively simple overall process framework. The local differentiation improves imprint quality without excessive 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
Reduces defects and variations in pattern dimensions by optimizing gas and light conditions, ensuring complete curing and proper contact of imprint material with the mold, particularly in the outer peripheral regions.
Implementation Method 1
Japanese Patent Laid-Open No. 2007-509769 describes that residual bubbles are suppressed by filling a space between a mold and a substrate with a gas having high solubility, high diffusibility, or both characteristics with respect to an imprint material.
Implementation Method 2
According to the photo-curing method, a mold is brought into contact with a photo-curable imprint material applied on a substrate (contact step), the imprint material is cured by light irradiation (curing step)
Implementation Method 3
In the imprint process on the outer peripheral region of the substrate, if the imprint process is performed in an atmosphere with sufficient oxygen, even if the imprint material adhering to the mold is irradiated with light, oxygen inhibits curing of the imprint material.
Data Source
AI summary
An imprint apparatus is provided. The apparatus includes a supplier configured to supply a gas to a space between a mold and an imprint material on a shot region, an irradiator configured to perform light irradiation, and a controller. A plurality of shot regions on a substrate include a full shot region having a size where a pattern region of the mold is fully transferred, and a partial shot region where only a part of the pattern region is transferred because of being located in an outer peripheral portion of the substrate. When performing an imprint process on the partial shot region, the controller reduces a supply amount of a gas from the supplier and increases an amount of irradiation light from the irradiator as compared to a case of performing the imprint process on the full shot region.