Immersion Lithography Drying Station Residual Liquid Removal
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Solution Overview
Problem
In immersion lithography, residual liquid on the substrate after exposure can cause resist deterioration, leading to defects, and existing methods do not effectively address this without compromising throughput.
Innovation Solution
A lithographic apparatus with a drying station integrated into the substrate unloading path and post-exposure handling module actively removes liquid from the substrate surface as it is transferred, ensuring complete passage through the drying station during handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is exposed to radiation beam via liquid in immersion lithography, then the manufacturing precision is improved, but residual liquid remains on the substrate surface causing defects
Solution Approach 1:
The drying station performs preliminary drying action on the substrate surface immediately after exposure and before the substrate leaves the lithographic apparatus. This preliminary action removes residual liquid that would otherwise cause resist deterioration and defects in subsequent processing steps.
Solution Approach 2:
The drying station extracts and removes the harmful residual liquid from the substrate surface. By taking out the liquid that remains after immersion lithography, the system prevents the liquid from causing resist deterioration while maintaining the benefits of immersion exposure.
2Reliability
If a drying station is added to remove liquid from substrate, then defects are reduced, but the device complexity increases
Solution Approach 1:
The drying station is merged with the existing substrate handling system and integrated into the substrate unloading path. By combining the drying function with the substrate transfer mechanism, the system achieves defect reduction without proportionally increasing overall device complexity.
Solution Approach 2:
The drying station is designed to work within the existing substrate handling infrastructure, utilizing the substrate unloading path and post-exposure handling module for its operation. This multi-functional integration allows the drying function to be achieved using existing system components and pathways.
3Reliability
If the substrate is transferred through a drying station, then liquid removal efficiency is improved, but the throughput may be affected
Solution Approach 1:
The drying station is positioned in the substrate unloading path, allowing continuous drying action to occur as substrates are transferred out of the lithographic apparatus. The drying process operates continuously without interrupting the substrate transfer flow, maintaining both efficiency and throughput.
Solution Approach 2:
The drying action is performed preliminarily during the substrate transfer process itself, rather than as a separate subsequent step. By incorporating drying into the unloading path, the system removes liquid efficiently while the substrate is already in motion, avoiding additional throughput reduction.
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 approach effectively reduces defects caused by residual liquid while maintaining the apparatus's throughput by ensuring efficient liquid removal during substrate handling.
Implementation Method 1
a drying station configured to actively remove liquid from a surface of the substrate
Data Source
AI summary
A lithographic apparatus includes a substrate table, a post-exposure handling module, a substrate handling robot and a drying station. The substrate table is configured to support a substrate for an exposure process. The post-exposure handling module is configured to handle the substrate post-exposure. The substrate handling robot is configured to transfer the substrate from the substrate table along a substrate unloading path into the post-exposure handling module. The drying station is configured to actively remove liquid from a surface of the substrate. The drying station is located in the substrate unloading path. The drying station is located in the post-exposure handling module. The post-exposure handling module may be a substrate handler.