Substrate Support Oxide Prevention via Positive Potential
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Solution Overview
Problem
Lithographic apparatuses face challenges in maintaining the flatness and uniform coefficient of friction of substrate supports due to non-uniform oxide growth on burls, leading to focus and overlay errors during substrate processing.
Innovation Solution
A system comprising a conductive or semi-conductive element contacting the substrate support and a charging device applying a positive potential to counteract electrochemical oxidation, preventing or reducing oxide growth, and potentially removing existing oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substrate support with burls is used to hold the substrate, then the substrate can be supported at multiple positions, but non-uniform oxide growth on the burls causes variations in flatness and coefficient of friction leading to focus and overlay errors
Solution Approach 1:
The patent applies a positive electrical potential to the substrate support to change its electrochemical state. This parameter change prevents oxide growth by creating an electrochemical environment that inhibits oxidation reactions on the burl surfaces, thereby maintaining uniform flatness and friction characteristics throughout the substrate support lifecycle
Solution Approach 2:
The patent converts the harmful oxidative environment into a beneficial protected state by applying positive potential. The oxidation that would normally degrade the burls is prevented, and the electrochemical protection mechanism transforms the potential harm of electrical potential application into the benefit of oxide prevention and surface property maintenance
2Ease of manufacture
If mechanical cleaning is used to remove contamination from the substrate support, then contamination can be removed, but the treatment tool may cause damage to the substrate support and interfere with production
Solution Approach 1:
The patent replaces the mechanical cleaning system with an electrochemical protection system. Instead of using physical treatment tools that mechanically contact and potentially damage the substrate support, the invention uses electrical potential application to prevent oxide formation, thereby eliminating mechanical wear and production interruptions
Solution Approach 2:
The patent applies protective electrical potential in advance to prevent oxide growth before it occurs. This preliminary protective action eliminates the need for subsequent cleaning operations, maintaining continuous production without interruptions for substrate support maintenance
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 solution effectively maintains the initial flatness and uniform friction of the substrate support, reducing oxide growth and preventing errors in substrate processing, thereby enhancing the precision and accuracy of lithographic processes.
Implementation Method 1
a charging device configured to apply a positive potential to the conductive or semi-conductive element with respect to the part of the substrate support that is covered by the conductive or semi-conductive element
Implementation Method 2
the positive potential is applied to the conductive or semi-conductive element with respect to the terminal end surfaces of the plurality of burls of the substrate support
Data Source
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AI summary
A system comprising: a substrate support configured to hold a substrate; a conductive or semi- conductive element contacting the substrate support and covering at least part of the substrate support; and a charging device configured to apply a positive potential to the conductive or semi-conductive element with respect to the part of the substrate support that is covered by the conductive or semi- conductive element.