Imprint Apparatus Dynamic Control Gain for Resin Curing
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Solution Overview
Problem
In imprint technology using a light curing method, high positioning accuracy and speed are required to transfer fine patterns onto substrates, but existing technologies face issues with pattern breakage due to excessive forces exerted on the resin during curing and mold release, and reduced control gain compromises positioning accuracy.
Innovation Solution
An imprint apparatus with a stage that adjusts its position control gain based on measured position errors, using a combination of fine-motion and coarse-motion stages, and a control unit that reduces the ratio of manipulating variables to position errors during resin curing, employing a flexure mechanism for mold support and non-contact linear motors for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high control gain is used to achieve high-speed movement and high-accuracy positioning, then positioning accuracy and movement speed are improved, but excessive force is exerted on the resin causing pattern breakage
Solution Approach 1:
The control gain is dynamically adjusted based on the curing state of the resin. During early curing when the resin is still soft, the control gain is reduced to minimize exerted force and prevent pattern breakage. As curing progresses and the resin hardens, the control gain can be increased to maintain positioning accuracy. This time-varying gain adjustment resolves the contradiction between maintaining high positioning accuracy and preventing pattern breakage.
Solution Approach 2:
The control parameter (gain) is changed according to the curing progression of the resin. By monitoring the curing state and adjusting the control gain accordingly, the system adapts to the changing mechanical properties of the resin, ensuring both accurate positioning and prevention of pattern breakage throughout the curing process.
2Object-affected harmful factors
If control gain is reduced to prevent pattern breakage, then pattern integrity is maintained, but positioning accuracy of the substrate stage decreases
Solution Approach 1:
Rather than using a static low gain that compromises positioning accuracy, the system employs dynamic gain adjustment. The control gain is temporarily reduced only during the critical early curing phase when the resin is vulnerable, while maintaining higher gain values during alignment and later curing stages when positioning accuracy is paramount. This resolves the contradiction by applying low gain only when necessary for pattern integrity.
Solution Approach 2:
The control gain is adjusted in periodic stages corresponding to different phases of the curing process. During alignment and initial contact, high gain ensures precise positioning. During the critical early curing phase, gain is reduced to protect the pattern. As curing completes and the resin hardens, gain can be increased again for subsequent operations, creating a periodic adjustment pattern that balances both requirements.
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 prevents pattern breakage while maintaining high positioning accuracy and speed, ensuring stable control system operation and precise pattern transfer without excessive force on the resin or mold.
Implementation Method 1
a fine-motion stage which is supported in a non-contact manner and on which positioning with six degrees of freedom can be performed by driving with linear motors
Implementation Method 2
positioning with a high accuracy on the basis of information concerning a position that is measured by a high-accuracy laser interferometer
Implementation Method 3
the resin is irradiated with light used to cure a resin, such as ultraviolet light, thereby curing the resin
Data Source
AI summary
An imprint apparatus is disclosed that forms, by pressing a resin applied onto a substrate and a mold against each other, a pattern on the substrate. The imprint apparatus includes a substrate stage that holds the substrate, and a control unit for controlling the position of the stage by outputting a manipulating variable on the basis of a position error between a position of the stage which has been measured by position measurement unit and a target position. The control unit reduces a ratio of the manipulating variable to the position error while the substrate and the mold are in contact with each other until mold release.