Lithography Support Table With Edge-Zone Thermal Conditioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of immersion fluid in lithographic apparatuses introduces heat load issues, leading to non-uniform image formation on substrates due to localized temperature changes caused by fluid handling and evaporation, resulting in overlay errors and critical dimension variations.
Innovation Solution
A support table with a conditioning system that supplies or removes heat energy, featuring a base surface with protruding burls, where the stiffness and heat transfer are greater at the substrate's edge than at its center, and a controller that adjusts heat transfer based on measured position to minimize temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If immersion fluid is used in the lithographic apparatus, then imaging resolution is improved, but temperature uniformity deteriorates due to localized heat load from fluid handling and evaporation
Solution Approach 1:
The support table is designed with spatially varying thermal properties: the outer region has higher heat transfer capability than the inner region. This is achieved through different structures (e.g., fins, channels, or material composition) in different zones of the support table, allowing localized heat management that compensates for the non-uniform heat generation from immersion fluid handling.
Solution Approach 2:
The patent changes the thermal parameters (heat transfer coefficient, thermal conductivity) of the support table across different spatial regions. By adjusting these parameters locally, the system compensates for the non-uniform temperature distribution caused by immersion fluid, maintaining overall temperature uniformity across the substrate.
2Stability of the object's composition
If the support table provides uniform heat transfer across the substrate, then thermal stability is improved, but the ability to compensate for localized heat load from immersion fluid deteriorates
Solution Approach 1:
The support table transitions from a uniform structure to a non-uniform structure with different thermal characteristics in different regions. The outer region is designed with enhanced heat transfer capabilities (e.g., through fins, increased surface area, or different material properties) to specifically address the localized heat load from immersion fluid, while the inner region maintains appropriate thermal characteristics for the center substrate area.
3Device complexity
If the support table structure is simplified, then device complexity is reduced, but the ability to control non-uniform temperature distribution deteriorates
Solution Approach 1:
Rather than using a complex multi-component system, the patent implements local quality variations within the support table itself through integrated structural features (such as varying thickness, embedded channels, or surface structures) that provide different thermal characteristics in different regions, achieving sophisticated temperature control without proportionally increasing device complexity.
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 configuration reduces temperature variations across the substrate, minimizing thermal expansion and contraction, and thereby improves the accuracy of image formation by maintaining uniform heat transfer and reducing overlay errors.
Implementation Method 1
a conditioning system, configured to supply heat energy to and/or remove heat energy from the support section... when a substrate is supported by the support section, it is thermally coupled to the support section such that, when the conditioning system supplies heat energy to or removes heat energy from the support section, energy in turn transfers from the support section to the substrate or to the support section from the substrate, respectively
Implementation Method 2
the burls are configured such that the stiffness of the burls in a direction parallel to the upper surface of the support section is greater for burls in contact with a first region of the substrate that is adjacent to an edge of the substrate than for burls in contact with a second region of the substrate that is at the center of the substrate
Implementation Method 3
the use of immersion fluid in lithographic apparatuses introduces heat load issues, leading to non-uniform image formation on substrates due to localized temperature changes caused by fluid handling and evaporation
Implementation Method 4
minimizing thermal expansion and contraction
Data Source
AI summary
A support table for a lithographic apparatus, the support table having a support section and a conditioning system, wherein the support section, the conditioning system, or both, is configured such that heat transfer to or from a substrate supported on the support table, resulting from the operation of the conditioning system, is greater in a region of the substrate adjacent an edge of the substrate than it is in a region of the substrate that is at the center of the substrate.