Substrate Drying with a Moving Gas Phase Layer for Pattern Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In substrate processing, fine patterns with high aspect ratios are prone to collapse due to the surface tension of processing liquids, especially when using Isopropyl alcohol (IPA), as existing methods struggle to efficiently exclude the liquid from the substrate surface without causing excessive heating or local evaporation, leading to pattern collapse and particle generation.
Innovation Solution
A substrate processing method involving the formation of a gas phase layer between the processing liquid and the substrate surface, where a light radiation unit heats the center portion to evaporate the liquid, forming an opening that expands while maintaining a gas phase layer on the inner circumferential edge, using a moving irradiation region and controlled heating to prevent excessive heating and pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate is heated to evaporate the liquid film of IPA, then the liquid film can be excluded from the substrate surface, but excessive heating causes local evaporation and liquid film splitting leading to pattern collapse
Solution Approach 1:
The patent applies local quality by creating a gas phase layer specifically at the center portion of the substrate where the liquid film needs to be excluded, while maintaining different temperature conditions in different regions. The moving irradiation region provides localized heating that moves across the substrate surface, preventing excessive concentration of heat in one area while still achieving effective liquid film exclusion where needed.
Solution Approach 2:
The patent employs dynamics by moving the irradiation region across the substrate surface during the drying process. This dynamic approach allows the heating zone to traverse the substrate, creating and maintaining a gas phase layer that moves with the irradiation region, thereby preventing static heat concentration and liquid film splitting while maintaining effective drying.
2Reliability
If a gas phase layer is formed to exclude liquid from the substrate, then surface tension action time is shortened preventing pattern collapse, but maintaining the gas phase layer requires precise control of heating to prevent excessive heating
Solution Approach 1:
The patent implements feedback control by continuously moving the irradiation region across the substrate surface. This movement creates a dynamic equilibrium where the gas phase layer is maintained in the previously irradiated area while the heating zone moves forward, preventing excessive temperature buildup. The system self-regulates by the interaction between the moving heat source and the substrate, maintaining reliable pattern stability through controlled temperature distribution.
3Productivity
If the liquid film is excluded by heating the entire substrate, then drying is achieved, but uniform heating is difficult to maintain and may cause overheating or insufficient drying in different regions
Solution Approach 1:
The patent uses dynamics to achieve uniform drying by moving the irradiation region across the substrate surface. This movement distributes the heating effect uniformly across different areas of the substrate over time, ensuring that all regions receive appropriate heat treatment for liquid film exclusion without requiring complex multi-zone heating systems. The dynamic scanning approach simplifies the heating control while maintaining drying 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
This method effectively excludes the processing liquid from the substrate surface, preventing pattern collapse and particle generation by shortening the time of surface tension action, maintaining the gas phase layer, and ensuring uniform heating, thus enhancing drying efficiency and pattern stability.
Implementation Method 1
a light radiation unit heats the center portion to evaporate the liquid, forming an opening
Implementation Method 2
a light radiation unit heats the center portion
Implementation Method 3
the surface tension of the liquid acts on a contact position between the liquid level and the pattern
Implementation Method 4
using a moving irradiation region and controlled heating to prevent excessive heating and pattern collapse
Data Source
AI summary
A substrate processing method includes a liquid film forming step of forming a liquid film, a liquid film heat retaining step of keeping the liquid film warm, a gas phase layer forming step of forming a gas phase layer which holds the processing liquid on a center portion of the liquid film, an opening forming step of forming an opening in the center portion of the liquid film by excluding the processing liquid held by the gas phase layer, a substrate rotating step of rotating the substrate around a rotation axis, and an opening expanding step of expanding the opening, while a state in which the gas phase layer is formed on an inner circumferential edge of the liquid film is maintained, by moving the irradiation region toward a circumferential edge portion of the substrate while the liquid film heat retaining step and the substrate rotating step are performed.