Substrate Drying with Localized Gas Layer Expansion
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Solution Overview
Problem
In substrate processing, fine patterns with high aspect ratios are prone to collapse during the drying process due to the surface tension of processing liquids, and existing methods struggle to efficiently exclude processing liquids from the substrate surface while maintaining a gas phase layer, leading to poor drying and pattern collapse.
Innovation Solution
A method involving the formation of a gas phase layer between the processing liquid and the substrate surface, where a light irradiation region is used to evaporate the processing liquid at the center of the substrate, creating an opening that expands as the gas phase layer moves towards the edge, while maintaining the liquid film warm to prevent evaporation and pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a gas phase layer is formed by heating the substrate to evaporate processing liquid, then the liquid is excluded from the substrate surface, but the substrate may be heated excessively causing local evaporation and liquid film splitting
Solution Approach 1:
The patent applies local quality by using a radiation unit to heat only a specific irradiation region on the substrate surface rather than heating the entire substrate. This localized heating approach allows the processing liquid to be evaporated and excluded from the substrate surface while preventing excessive heating of the whole substrate that would cause liquid film splitting. The irradiation region is carefully controlled to be smaller than the substrate, creating a temperature gradient that achieves effective drying without harmful thermal effects.
2Productivity
If the substrate is heated to form a gas phase layer, then processing liquid is excluded from the surface, but the processing liquid may evaporate locally and split the liquid film
Solution Approach 1:
The patent creates a localized gas phase layer in the irradiation region by heating only that specific area with the radiation unit. This localized approach allows the processing liquid to be effectively excluded from the substrate surface through controlled evaporation in the irradiation region, while the rest of the substrate maintains a stable liquid film. The irradiation region is positioned and sized to achieve liquid exclusion without causing liquid film splitting.
Solution Approach 2:
The patent performs preliminary action by forming a gas phase layer in the irradiation region before the processing liquid can evaporate locally and split the liquid film. The radiation unit is activated to create the gas phase layer and initiate liquid exclusion in a controlled manner, preventing the harmful local evaporation and liquid film splitting that would occur with uncontrolled heating.
3Productivity
If the entire substrate is heated to exclude the liquid film, then the liquid is removed from the surface, but the processing time is extended and energy consumption increases
Solution Approach 1:
The patent achieves rapid liquid exclusion by heating only the irradiation region with the radiation unit rather than heating the entire substrate. This localized heating approach concentrates thermal energy where it is most needed for liquid evaporation and exclusion, significantly reducing processing time and energy consumption compared to whole-substrate heating methods.
Solution Approach 2:
The patent replaces conventional thermal conduction heating with radiation heating. The radiation unit directly radiates energy to the processing liquid and substrate surface in the irradiation region, enabling faster and more efficient evaporation and liquid exclusion without the thermal lag and energy loss associated with conventional heating methods.
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 effectively excludes processing liquids from the substrate surface, preventing pattern collapse and particle generation by shortening the time of surface tension action on fine patterns and maintaining a stable gas phase layer, ensuring thorough drying without excessive heating.
Implementation Method 1
evaporating the processing liquid in contact with a center portion of an upper surface of the substrate and forming a gas phase layer which is in contact with the upper surface of the substrate and holds the processing liquid on a center portion of the liquid film by irradiating an irradiation region set on the center portion of the upper surface of the substrate with light from a radiation unit
Implementation Method 2
irradiating an irradiation region set on the center portion of the upper surface of the substrate with light from a radiation unit which faces the upper surface of the substrate to heat the center portion of the upper surface of the substrate
Implementation Method 3
a spin chuck that rotates the substrate around a rotation axis
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.