Substrate Drying via IPA Impingement and DIW Buffer Film
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Solution Overview
Problem
Existing dry methods for substrate processing after chemical liquid processing, such as using low surface tension liquids like isopropyl alcohol (IPA), often result in uneven IPA replacement areas and the formation of empty spaces, which can lead to particle generation during the drying process.
Innovation Solution
A method and apparatus that form a high surface tension liquid film on a substrate, replace it with low surface tension liquid (IPA) by impinging IPA at the center, and continue supplying high surface tension liquid to prevent 'fingering' by injecting DIW outside the IPA replacement area, ensuring even IPA extension and effective drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low surface tension liquid (IPA) is supplied to replace high surface tension liquid film on substrate center area, then drying efficiency is improved, but IPA replacement area becomes uneven and empty spaces are generated
Solution Approach 1:
A high surface tension liquid film (DIW) is formed on the substrate surface before IPA replacement. This preliminary DIW film acts as a buffer that enables uniform IPA replacement across the substrate surface, preventing the generation of empty spaces while maintaining high drying efficiency.
Solution Approach 2:
The high surface tension liquid (DIW) serves as an intermediary substance between the substrate and the low surface tension liquid (IPA). By introducing this intermediate layer, the patent achieves uniform IPA replacement without direct IPA-substrate contact issues, thereby preventing empty space formation while maintaining drying efficiency.
2Productivity
If IPA is discharged on center area of substrate, then drying process is accelerated, but particle generation risk increases due to uneven replacement area
Solution Approach 1:
The substrate is first treated with a high surface tension liquid (DIW) to form a uniform liquid film before IPA replacement. This preliminary treatment ensures that subsequent IPA replacement occurs uniformly across the entire substrate surface, eliminating the conditions that lead to particle generation while maintaining rapid drying performance.
Solution Approach 2:
The patent changes the surface tension parameter of the liquid on the substrate by first applying high surface tension liquid (DIW) and then replacing it with low surface tension liquid (IPA). This controlled parameter change ensures uniform liquid distribution and prevents the formation of empty spaces that would otherwise lead to particle generation during drying.
3Productivity
If DIW is replaced with IPA in center area only, then drying efficiency is improved, but empty spaces and fingering defects are generated
Solution Approach 1:
A complete DIW liquid film is formed on the entire substrate surface before IPA replacement begins. This preliminary uniform coating ensures that when IPA replaces DIW, the replacement occurs evenly across the whole substrate rather than creating localized empty spaces or fingering defects, while still maintaining high drying efficiency through the low surface tension of IPA.
Solution Approach 2:
The patent utilizes the parameter change in surface tension by first establishing a high surface tension DIW film and then introducing low surface tension IPA. This controlled parameter transition ensures uniform liquid film composition across the substrate, preventing fingering defects and empty spaces while achieving efficient drying through the final low surface tension state.
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 ensures even IPA replacement and prevents particle formation during drying, allowing for efficient and effective substrate drying without generating empty spaces.
Implementation Method 1
The low surface tension liquid contains an organic solvent component such as isopropyl alcohol (IPA) having a lower surface tension than purified water (DIW)
Implementation Method 2
a spin chuck rotatably provided in the chamber and configured to support a substrate
Data Source
AI summary
A substrate processing method includes forming a high surface tension liquid film by supplying high surface tension liquid on a substrate surface, replacing the high surface tension liquid film with low surface tension liquid by supplying the low surface tension liquid to a center area of a substrate so that the low surface tension liquid impinges on the high surface tension liquid film formed on the center area of the substrate, and supplying high surface tension liquid for a predetermined period of time during the supplying the low surface tension liquid.