Substrate Support Inert Gas Layout to Prevent Oxidation Distortion
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Solution Overview
Problem
The formation of an oxide film on the substrate support due to oxidation, which leads to degradation in flatness and pattern distortion, is exacerbated by the presence of oxygen and water, particularly in immersion lithography processes.
Innovation Solution
A substrate holding system with a substrate support configured to supply inert gas through ports and conduits to the region between the substrate and support, inhibiting oxidation by maintaining an inert gas environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the substrate support is surrounded by air during immersion lithography, then the substrate support can be easily accessed and operated, but oxygen and water in the air cause oxidation of the substrate support surface
Solution Approach 1:
The patent introduces an inert gas (such as nitrogen or argon) to displace air from the region between the substrate and substrate support during immersion lithography. This creates an oxygen-free environment that prevents oxidation of the substrate support surface while maintaining ease of operation. The inert gas is supplied through a gas delivery system that introduces gas at the periphery and extracts it from the center region.
2Ease of manufacture
If an oxide film forms on the substrate support surface, then the substrate support can be manufactured with standard materials, but the oxide film degrades flatness and causes pattern distortion
Solution Approach 1:
By maintaining an inert gas environment between the substrate and substrate support, the patent prevents oxide film formation on the substrate support surface. This preserves the original flatness and optical properties of the substrate support, ensuring high manufacturing precision for lithographic patterning while allowing the use of standard support materials.
Solution Approach 2:
The patent applies preliminary protective action by introducing inert gas before oxidation can occur. The gas delivery system is designed to establish an oxygen-free environment in advance, preventing the harmful oxidation process rather than attempting to correct it after damage occurs.
3Productivity
If water is present in the region between substrate and support, then immersion lithography can proceed, but water attracts radially outward water and increases adhesive capillary forces causing distortion
Solution Approach 1:
The patent replaces air with an inert gas environment in the region between the substrate and substrate support. This prevents the formation of water bridges and eliminates adhesive capillary forces that would otherwise cause substrate distortion during immersion lithography, while still allowing the immersion process to proceed.
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
Reduces oxidation and maintains substrate support flatness, thereby improving wafer load grid accuracy and extending the substrate support's lifetime.
Implementation Method 1
Oxygen and water within the air can cause the substrate support to undergo oxidation, in which a top surface of the substrate support is chemically converted into an oxide film
Implementation Method 2
the oxide film is hydrophilic, so in substrate supports used in conjunction with water as an immersion fluid, the water radially outward of the substrate support is attracted into the region between the substrate and the substrate support. This increases adhesive capillary forces
Data Source
AI summary
A substrate holding system includes a substrate support configured to support a substrate, a gas source, and a plurality of conduits. The substrate support includes a first port and a plurality of second ports radially outwards of the first port. The first port and the plurality of second ports are configured to be in fluid communication with the gas source. The gas source is configured to supply an inert gas to a region between the substrate and the substrate support via the first port and the plurality of second ports. The substrate holding system is configured such that the inert gas can be supplied to the region between the substrate and the substrate support through the first port or the plurality of second ports. The substrate holding system is configured to extract gas from the region between the substrate and the substrate support through the plurality of second ports.