Substrate Drying Sequence Using Diluted IPA for 3D Pattern Stability
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Solution Overview
Problem
In the drying treatment step of substrate processing, patterns on the substrate surface tend to collapse due to the surface tension of rinse liquids, which invades the pattern structures. This collapse can be prevented by applying a water-repellent protective film, but existing methods are inefficient in ensuring uniform treatment, especially for substrates with three-dimensional structures.
Innovation Solution
A substrate treatment method and apparatus that involves a rinsing step followed by immersion in a diluted isopropyl alcohol (IPA) stored in a treatment tank. After the immersion, the substrate undergoes a first IPA treatment, and then a water-repellent treatment is applied. The apparatus includes a chamber, a treatment tank, a substrate holding part, liquid supply parts for IPA and water repellent agents, and a control part that coordinates the treatment steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a water-repellent protective film is applied to prevent pattern collapse, then pattern stability is improved, but treatment uniformity deteriorates due to insufficient IPA replacement on three-dimensional structures
Solution Approach 1:
The substrate is immersed in diluted IPA before the water-repellent treatment. This preliminary immersion action ensures that IPA thoroughly penetrates and replaces rinse liquid within three-dimensional pattern structures beforehand, creating a uniform foundation for subsequent water-repellent treatment and preventing non-uniform treatment effects
Solution Approach 2:
The patent uses diluted IPA (isopropyl alcohol) instead of pure IPA or other solvents. The dilution parameter is optimized to enhance capillary action and penetration into three-dimensional structures while maintaining effective surface tension characteristics. This parameter change ensures uniform IPA replacement throughout complex substrate structures
2Reliability
If rinse liquid is used for substrate treatment, then cleaning effectiveness is improved, but pattern collapse occurs due to surface tension invasion
Solution Approach 1:
IPA serves as an intermediary substance between the rinse liquid and the water-repellent protective film. It first replaces the rinse liquid uniformly throughout the substrate structure, then provides a compatible base for water-repellent treatment, preventing direct contact between high-surface-tension water-based liquids and sensitive patterns
Solution Approach 2:
The patent changes the liquid parameter from water-based rinse liquid with high surface tension to IPA-based liquid with lower surface tension. This parameter change reduces the harmful capillary invasion force while maintaining cleaning effectiveness and enabling uniform penetration into three-dimensional structures
3Manufacturing precision
If vapor phase treatment is used for water-repellent coating, then treatment uniformity is improved, but treatment time increases
Solution Approach 1:
The substrate undergoes preliminary immersion in diluted IPA to uniformly saturate the structure before vapor phase water-repellent treatment. This preliminary action reduces the time required for vapor penetration and reaction, as the pre-imbibed liquid facilitates faster and more uniform vapor phase treatment
Solution Approach 2:
The process transitions continuously from liquid phase immersion to vapor phase treatment without removing the substrate. This continuous action maintains treatment momentum and ensures uniform coverage throughout the three-dimensional structure, reducing total treatment time while preserving uniformity
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 prevents pattern collapse on substrates by ensuring thorough replacement of the substrate surface with IPA and subsequent water-repellent treatment, even for substrates with complex three-dimensional structures. This results in improved uniformity and effectiveness of the substrate treatment process.
Implementation Method 1
a water repellent agent which remains on a surface of the substrate is removed by being replaced with an isopropyl alcohol (IPA)
Implementation Method 2
the vapor of the isopropyl alcohol is supplied to the substrate
Implementation Method 3
the vapor of the water repellent agent is supplied to the substrate
Implementation Method 4
a pattern formed on the surface of the substrate may collapse. Collapse of a pattern is caused due to the surface tension of a rinse liquid
Data Source
AI summary
A substrate treatment method includes a rinsing step of performing treatment of a substrate with a rinse liquid, an immersing step of immersing the substrate in a diluted isopropyl alcohol (dIPA) stored in a treatment tank after the rinsing step, a first isopropyl alcohol treatment step of performing treatment of the substrate with an isopropyl alcohol after the immersing step, and a water-repellent treatment step of performing water-repellent treatment of the substrate after the first isopropyl alcohol treatment step.