Segmented Chuck Design for Substrate Flatness Control
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Solution Overview
Problem
Existing substrate-holding apparatuses, particularly in lithography systems, face challenges in maintaining the flatness of thin substrates due to contact-induced deformation when using conventional chuck designs that rely on gas exhaustion for holding.
Innovation Solution
A chuck design featuring support portions with four convex and three concave sections arranged in a specific pattern, where the concave sections are connected to a common exhaust system, preventing substrate deformation and maintaining flatness by controlling pressure and minimizing contact with non-support regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional chuck design with continuous contact surface is used to hold substrates, then the substrate can be securely held, but the flatness of thin substrates is degraded due to contact-induced deformation
Solution Approach 1:
The chuck surface is segmented into multiple convex portions and concave portions instead of a continuous contact surface. The substrate back surface contacts only the convex portions while concave portions remain non-contacting, preventing deformation while maintaining secure holding through localized contact points
Solution Approach 2:
Different regions of the chuck surface have different functions: convex portions provide contact and holding force, while concave portions provide non-contacting support and flatness maintenance. This local differentiation allows the chuck to simultaneously secure the substrate and preserve its flatness
2Force
If gas exhaustion is applied over the entire chuck surface to hold substrates, then strong holding force is achieved, but substrate deformation occurs due to pressure distribution issues
Solution Approach 1:
The gas exhaustion system is segmented to exhaust gas only from concave portions rather than the entire surface. This creates localized pressure zones that provide strong holding force through convex portions while preventing uniform pressure-induced deformation
Solution Approach 2:
Instead of exhausting gas from the entire surface as in conventional designs, the invention inverts the approach by exhausting gas only from concave non-contacting portions, allowing convex portions to provide contact force while concave portions maintain flatness through controlled pressure release
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
The design effectively maintains high flatness of substrates, even when they are thin, reducing deformation and particle attachment, and prevents suction marks, thereby enhancing the accuracy of exposure processes in lithography.
Implementation Method 1
gas in the concave portion is exhausted to hold a substrate
Data Source
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AI summary
A chuck according to an embodiment of the present invention includes first and second support portions 10 each of which has a repetition structure of a convex portion 11 and a concave portion 13 on a base. A substrate is held by bringing each convex portion 11 into contact with the substrate and exhausting gas in each concave portion 13 such that the concave portion 13 has a negative pressure with respect to a space between the first support portion 10 and the second support portion 10. At least one support portion of the first support portion 10 and the second support portion 10 includes at least four convex portions 11 and three concave portions 13.