Substrate Back Surface Cleaning for EUV Exposure
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Solution Overview
Problem
Substrate processing apparatuses face contamination issues during film formation, leading to irregularities on the substrate's back surface, which can cause dimensional errors and shape defects during exposure processing, especially when using EUV exposure techniques that require a high vacuum environment.
Innovation Solution
A substrate processing apparatus with a photosensitive film forming unit and a back surface cleaning unit that cleans the substrate's back surface after film formation, using a transport device with multiple holders to maintain the substrate's cleanliness during transfer to and from the exposure device, preventing contaminants from adhering to the holders and ensuring a clean substrate is transported in the exposure device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single holder is used to transport the substrate before and after exposure processing, then the device complexity is reduced, but the substrate becomes contaminated after exposure processing and the exposure device vacuum deteriorates
Solution Approach 1:
The transport device is divided into a first holder for transporting the substrate before exposure processing and a second holder for transporting the substrate after exposure processing. This segmentation prevents contaminants from the post-exposure substrate from adhering to the holder that will hold the clean pre-exposure substrate, thereby preventing contamination while maintaining operational efficiency.
Solution Approach 2:
The first holder is dedicated to transporting clean substrates before exposure and is kept free from contaminants. After the substrate is transferred to the exposure device, the first holder is effectively discarded for that cycle and will not come into contact with contaminated substrates, thus preserving its cleanliness for the next clean substrate transport.
2Ease of operation
If the substrate is transported in air between processing units, then the ease of operation is improved, but the substrate picks up contaminants and the vacuum degree in the exposure device deteriorates
Solution Approach 1:
The substrate transport between the substrate processing apparatus and the exposure device is performed in a vacuum environment or inert atmosphere rather than air. This prevents the substrate from picking up contaminants during transport while maintaining ease of operation through automated transfer mechanisms.
Solution Approach 2:
A vacuum transfer chamber or interface chamber serves as an intermediary environment between the substrate processing apparatus and the exposure device. The substrate is transferred through this controlled environment that maintains vacuum conditions, preventing contaminant adhesion while enabling convenient automated transport.
3Manufacturing precision
If exposure processing is performed in vacuum environment, then the manufacturing precision is improved, but the operation rate decreases due to frequent vacuum maintenance
Solution Approach 1:
The substrate is cleaned on its back surface before exposure processing to remove all potential contaminants. This preliminary cleaning action ensures that the substrate will not release contaminants during exposure processing, thereby maintaining vacuum quality and reducing the frequency of vacuum maintenance operations, which improves the operation rate while preserving manufacturing precision.
Solution Approach 2:
The back surface cleaning unit performs preliminary anti-contamination action by removing contaminants from the substrate back surface before the substrate enters the vacuum exposure environment. This prevents contaminants from adhering to the substrate or being released into the vacuum chamber during exposure, thereby maintaining vacuum integrity and reducing maintenance frequency.
Data Source
AI summary
A substrate processing method for a substrate having a photosensitive film on a top surface thereof, includes cleaning a back surface of the substrate after the formation of the photosensitive film and before exposure processing; transporting the substrate to a temperature adjuster such as a cooling unit, while holding the substrate with a first holder; adjusting a temperature of the substrate with the temperature adjuster; transporting the substrate from the temperature adjuster to the exposure device with a second holder; and transporting the substrate after the exposure processing to a first platform while holding the substrate with a third holder.