Lithography Substrate Holding Force Control for Overlay Precision
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Solution Overview
Problem
Existing lithography devices face challenges in achieving high precision in transferring patterns from molds to substrates due to positional deviations and substrate deformations, which affect overlapping precision.
Innovation Solution
A lithography device equipped with a substrate holding unit that measures and controls the holding force to minimize overlapping errors by acquiring relationships among positional deviations, substrate deformation, and holding forces, using a control unit to adjust pressures in partitioned regions to correct substrate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is placed on the substrate holding unit, then the substrate is held for pattern transfer, but positional deviation occurs causing overlapping precision to deteriorate
Solution Approach 1:
The system measures the actual positional deviation of the substrate after placement, then feeds this information back to the control unit which adjusts the holding force accordingly. This closed-loop feedback mechanism compensates for positional deviations and restores overlapping precision.
Solution Approach 2:
The control unit changes the holding force parameter based on the measured positional deviation. By adjusting the magnitude of the holding force, the system compensates for positional deviations and maintains accurate pattern overlap.
2Manufacturing precision
If holding force is increased to reduce positional deviation, then overlapping precision improves, but substrate deformation increases affecting pattern accuracy
Solution Approach 1:
The control unit optimizes the holding force parameter to achieve the minimum force required to prevent excessive substrate deformation. By precisely controlling this parameter, the system maintains substrate shape while achieving adequate positional stability.
Solution Approach 2:
The system replaces purely mechanical holding with a controlled force application system that uses measurement feedback. Instead of relying on fixed mechanical clamping, the system dynamically adjusts holding force based on actual positional deviation, reducing unnecessary mechanical stress on the substrate.
3Ease of operation
If the substrate holding unit applies uniform pressure, then substrate is easily held, but positional deviation and overlapping error increase
Solution Approach 1:
The control unit applies different holding forces to different regions of the substrate based on local positional deviation requirements. Instead of uniform pressure, the system selectively adjusts force distribution to achieve optimal holding while minimizing overall positional deviation.
Solution Approach 2:
The substrate holding unit is divided into multiple independent pressure control regions. Each region can be controlled separately, allowing the system to segment the holding force application and optimize it for different areas of the substrate to improve overall positioning accuracy.
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
Improves overlapping precision by accurately aligning and forming patterns on substrates, reducing errors through controlled pressure adjustments based on measured positional deviations and substrate deformation.
Implementation Method 1
a substrate holding unit configured to hold the substrate; an acquisition unit configured to acquire relationships among an amount of positional deviation of the substrate relative to the substrate holding unit, a holding force applied to at least a part of the substrate to hold the substrate
Implementation Method 2
If positional deviation occurs, there is a problem that deformation of the substrate may change and an optimal value for overlapping precision may change
Data Source
AI summary
A lithography device includes: a pattern forming unit that forms a pattern in a shot region on a substrate held by a substrate holding unit by using a pattern unit; an acquisition unit that acquires relationships among the amount of positional deviation of the substrate relative to the substrate holding unit, a holding force applied to at least a part of the substrate to hold the substrate, and an overlapping error between the substrate and the pattern unit; a measurement unit that measures the amount of positional deviation of the substrate relative to the substrate holding unit; and a control unit that controls the holding force to reduce the overlapping error between the substrate and the pattern unit on the basis of the amount of positional deviation measured by the measuring unit and the relationships acquired by the acquisition unit.