Substrate Surface Drying via Hydrophobic-Hydrophilic Liquid Replacement
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Solution Overview
Problem
Conventional drying techniques leave nonvolatile impurities in the concave portions of concavo-convex patterns during substrate processing, such as semiconductor wafers and FPD substrates.
Innovation Solution
A substrate processing method involving water-repellent treatment, hydrophobic and hydrophilic liquid replacements, and controlled drying steps to minimize liquid evaporation, using 1H,1H,2H,2H-perfluoro decyltriethoxysilane (FDTS) as a water repellent agent to enhance hydrophobicity and facilitate hydrophilic liquid flow for impurity reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional drying techniques (vaporization by heating or decompression) are used to dry the substrate, then the drying effect is achieved, but nonvolatile impurities remain in the concave portions of the pattern
Solution Approach 1:
The patent changes the physical parameters of the processing liquid by using a solvent with a lower boiling point than water (such as alcohol or isopropanol). This parameter change allows the liquid to be removed at lower temperatures through evaporation rather than vaporization by heating or decompression, thereby preventing nonvolatile impurities from remaining in the concave portions of the pattern while still achieving thorough drying
Solution Approach 2:
The patent utilizes the phase transition from liquid to gas through natural evaporation of the low-boiling-point solvent, rather than forced vaporization by heating or decompression. This controlled phase transition allows the solvent to evaporate completely without leaving nonvolatile impurities behind in the pattern's concave portions
2Manufacturing precision
If a large amount of liquid is vaporized or evaporated to achieve drying, then the drying effect is improved, but energy consumption increases and impurities may remain
Solution Approach 1:
The patent changes the boiling point parameter of the processing liquid by selecting solvents with lower boiling points than water. This allows the liquid to evaporate at lower temperatures with less energy input, reducing energy consumption while still achieving effective drying without leaving impurities in the pattern
3Manufacturing precision
If water is used as the processing liquid, then cleaning effectiveness is high, but drying difficulty increases due to high surface tension and evaporation rate
Solution Approach 1:
The patent changes the surface tension and evaporation rate parameters by replacing water with organic solvents that have lower surface tension and higher volatility. This makes the drying process easier by allowing the liquid to spread more uniformly and evaporate completely without leaving residues, while maintaining cleaning effectiveness
Solution Approach 2:
The patent uses a solvent that replicates the cleaning function of water but with improved drying characteristics. The organic solvent copies the cleaning effectiveness while possessing superior evaporation properties that facilitate easier and more complete drying without impurity deposition
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
The method effectively reduces impurities in concave portions by promoting hydrophilic liquid flow and minimizing evaporation, ensuring thorough drying without residual contaminants.
Implementation Method 1
a water-repellent treatment step of performing a water-repellent treatment on the major surface of the substrate to supply a water repellent agent-containing liquid to the major surface of the substrate and to change a contact angle of pure water with respect to a flat surface to 90° or greater
Implementation Method 2
a hydrophobic liquid replacement step of, after the water-repellent treatment step, supplying a hydrophobic liquid to the major surface of the substrate and replacing the water repellent agent-containing liquid on the major surface of the substrate with the hydrophobic liquid
Implementation Method 3
a hydrophilic liquid replacement step of, after the hydrophobic liquid replacement step, supplying a hydrophilic liquid that is mixable with the hydrophobic liquid and that has hydrophilicity higher than the hydrophobic liquid to the major surface of the substrate and replacing the hydrophobic liquid on the major surface of the substrate with the hydrophilic liquid
Implementation Method 4
a drying step of, after the hydrophilic liquid replacement step, drying the major surface of the substrate by causing the hydrophilic liquid on the major surface of the substrate to flow and by removing the hydrophilic liquid from the major surface of the substrate
Data Source
AI summary
In this substrate processing method, a water-repellent treatment is performed on a upper surface of a substrate so as to change the contact angle of pure water with respect to a flat surface to 90° or greater, and then a hydrophobic liquid is supplied to the upper surface of the substrate, thereby replacing a water repellent agent-containing liquid on the upper surface of the substrate with the hydrophobic liquid. After the hydrophobic liquid replacement step, a hydrophilic liquid is supplied to the upper surface of the substrate, thereby replacing the hydrophobic liquid on the upper surface of the substrate with the hydrophilic liquid. After the hydrophilic liquid replacement step, the hydrophilic liquid on the upper surface of the substrate is caused to flow and is removed from the upper surface of the substrate, and the upper surface of the substrate is thereby dried.