Imprint Apparatus Alignment Control via Periodic Rotation
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Solution Overview
Problem
The alignment between the imprint region of a substrate and a mold in imprint apparatuses is challenging due to viscoelasticity, which causes overshooting and convergence issues during relative movement, especially when the substrate and mold are rapidly moved for alignment.
Innovation Solution
An imprint apparatus with a controller that performs a combination of translation and rotation operations between the mold and the substrate, including a first and second rotation operation with opposite rotation directions, to manage viscoelasticity and prevent overshooting by creating a low velocity region for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the substrate and mold are rapidly moved for alignment, then alignment speed is improved, but overshooting occurs due to viscoelasticity causing alignment convergence to fail
Solution Approach 1:
The alignment operation is divided into multiple periodic stages: a first operation moving in a first direction, followed by a second operation moving in a second direction opposite to the first. This periodic back-and-forth movement allows the viscoelastic imprint material to gradually adapt to velocity changes, preventing sudden overshooting while achieving alignment convergence through repeated cycles of adjustment.
2Loss of time
If the velocity of relative movement is increased, then alignment time is reduced, but the property of viscoelasticity rapidly changes causing overshooting
Solution Approach 1:
By implementing periodic operations with alternating directions, the system can maintain higher average velocities while ensuring that instantaneous velocity changes remain controlled. The alternating first and second operations create a rhythm of movement that prevents the viscoelastic material from experiencing sustained high-velocity shocks, thereby maintaining property stability and ensuring convergence.
Solution Approach 2:
The alignment process dynamically adjusts the velocity profile by alternating between first and second operations. Rather than maintaining a constant high velocity that would cause property changes, the system dynamically modulates velocity through periodic direction changes, allowing the viscoelastic material to adapt progressively and achieve alignment without overshooting.
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 ensures accurate alignment by controlling relative velocities and positions, reducing overshooting and improving alignment convergence, thereby enhancing the precision and efficiency of the imprint process.
Implementation Method 1
The imprint material has a property called viscoelasticity having both viscosity and elasticity. Hence, when the substrate and the mold are relatively moved in a direction along the surface, a shear force is generated in a direction that prevents relative movement due to viscoelasticity.
Data Source
AI summary
An imprint apparatus forms a pattern on an imprint region of a substrate by bringing a mold into contact with an imprint material on the imprint region and curing the imprint material. The apparatus includes a controller for controlling an alignment operation of adjusting relative position between the mold and the imprint region in a state that the mold is in contact with the imprint material. The alignment operation includes a translation operation of performing relative translation between the imprint region and the mold, and a rotation operation of performing relative rotation between the imprint region and the mold. The rotation operation includes a first operation and a second operation, and a relative rotation direction between the imprint region and the mold in the second operation is opposite to a relative rotation direction between the imprint region and the mold in the first operation.