Dynamic Gain Control for Imprint Alignment Speed
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Solution Overview
Problem
The alignment between a mold and a substrate in imprint apparatuses is slow due to the viscoelasticity of the imprint material, leading to reduced throughput, as the proportional gain for driving the stage needs to be reduced when the distance between the mold and substrate becomes constant, increasing the time required for alignment.
Innovation Solution
An imprint apparatus with a driving unit, measurement unit, and control unit that measures position deviations and adjusts the amplification factor of the command value for alignment control, allowing a higher amplification factor when the distance is maintained within a target range, thereby increasing the driving force during contact and reducing alignment time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the proportional gain is reduced when the distance between the mold and substrate becomes constant, then the alignment precision is improved, but the alignment time increases
Solution Approach 1:
The patent applies dynamics by making the proportional gain adjustable rather than fixed. The control system dynamically changes the proportional gain based on the contact state between the mold and imprint material. During the approach phase, a first proportional gain is used, and after contact is detected, a second proportional gain (higher than the first) is applied. This dynamic adjustment allows the system to achieve both precise alignment and reduced alignment time.
Solution Approach 2:
The patent implements parameter changes by modifying the proportional gain parameter in the control system based on the operational phase. The proportional gain is changed from a first value during the approach phase to a second value (higher than the first) after contact between the mold and imprint material is detected. This parameter change enables the system to optimize both alignment precision and speed at different stages of the process.
2Productivity
If the proportional gain is increased to reduce alignment time, then the throughput is improved, but the alignment precision deteriorates
Solution Approach 1:
The control system dynamically adjusts the proportional gain based on the contact state. During the approach phase before contact, a lower proportional gain is used to ensure precision. After contact between the mold and imprint material is detected, the system switches to a higher proportional gain to accelerate alignment and improve throughput. This dynamic switching resolves the contradiction between speed and precision.
Solution Approach 2:
The patent employs periodic action by dividing the alignment process into distinct phases with different control parameters. The first phase (approach phase) uses one proportional gain setting, and the second phase (contact phase) uses another setting. This periodic switching of control parameters allows the system to optimize performance for each phase, achieving both precision and speed.
3Speed
If the proportional gain is maintained at a high level during contact, then the alignment speed is improved, but the stability of the contact state deteriorates
Solution Approach 1:
The system dynamically adjusts the proportional gain based on the contact state between the mold and imprint material. During the approach phase, a lower gain maintains stability. After contact is detected, the system switches to a higher gain to improve alignment speed while the contact state itself provides inherent stability. This dynamic adjustment resolves the contradiction between speed and stability.
Solution Approach 2:
The patent uses feedback by detecting the contact state between the mold and imprint material to determine when to switch proportional gain values. The contact detection mechanism provides feedback about the system state, allowing the controller to adjust the proportional gain appropriately. This feedback mechanism ensures that high gain is only applied when the contact state provides sufficient stability.
Data Source
AI summary
The present invention provides an imprint apparatus which forms an imprint material on a substrate using a mold, comprising a driving unit driving at least one of the mold and the substrate, a measurement unit measuring a position deviation amount between the mold and the substrate, and a control unit controlling alignment between the mold and the substrate based on the position deviation amount, wherein in a first period from a start of contact between the mold and the imprint material until a distance between the mold and the substrate falls within a target range, and a second period in which the distance is maintained, the control unit obtains a command value for controlling the driving unit and controls the driving unit such that a amplification factor of the command value in the second period is larger than that in the first period.