Substrate Processing Apparatus for Pattern Collapse Prevention
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Solution Overview
Problem
In substrate processing, fine patterns with high aspect ratios are prone to collapse during drying due to surface tension issues, especially when using water as a rinse liquid, and existing methods face challenges in rotating substrates while heating with a hot plate, leading to incomplete processing and drying inefficiencies.
Innovation Solution
A method involving a substrate processing apparatus that rotates the substrate horizontally, forms a liquid film of a first organic solvent like IPA, supplies vapor of a second organic solvent to heat the substrate without direct contact, and then dries the substrate by stopping rotation and bringing the heater unit into contact, effectively managing surface tension and ensuring thorough processing and drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water is used as a rinse liquid, then the substrate is effectively rinsed, but pattern collapse occurs due to high surface tension during spin drying
Solution Approach 1:
The patent changes the physical parameter of surface tension by replacing water with organic solvents (IPA, ethyl carbonate) that have lower surface tension. This parameter change prevents pattern collapse during drying while maintaining effective rinsing capability
Solution Approach 2:
The patent introduces an intermediary substance (organic solvent film) between the water and the pattern structure. The organic solvent acts as a mediator that reduces surface tension effects on the pattern while still allowing effective rinsing
2Temperature
If the substrate is heated by a hot plate in contact with the substrate, then heating efficiency is high, but the substrate cannot be rotated during heating
Solution Approach 1:
The patent replaces the mechanical contact heating system (hot plate) with a thermal field system (infrared radiation heater). This substitution allows the substrate to be heated efficiently through radiation while maintaining rotation capability, as there is no mechanical contact required
Solution Approach 2:
The patent utilizes the rotation of the substrate as a dynamic mechanical action to distribute the organic solvent film uniformly during infrared heating, achieving both heating and film formation simultaneously through combined thermal and mechanical effects
3Device complexity
If the substrate is not rotated during heating with organic solvent film, then heating is simple, but the liquid film evaporates partially and exposes the upper surface
Solution Approach 1:
The patent introduces dynamic rotation of the substrate during infrared heating and organic solvent film formation. This dynamic action ensures uniform distribution of the liquid film and prevents localized evaporation, maintaining film integrity while enabling effective processing
4Device complexity
If the substrate is dried by spin drying, then the drying process is simple, but rinse liquid remains inside fine patterns causing pattern collapse
Solution Approach 1:
The patent changes the surface tension parameter by using organic solvents instead of water, and modifies the drying mechanism from spin drying to infrared heating evaporation. This parameter change allows effective removal of rinse liquid from fine patterns without causing pattern collapse
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 efficiently processes and dries substrates by reducing surface tension and ensuring uniform heating, preventing pattern collapse and achieving excellent substrate treatment even with volatile organic solvents, while allowing for reliable switching between heating and drying states.
Implementation Method 1
a heater unit 6 that has a facing surface 6a facing a lower surface of the substrate W and is relatively movable with respect to the substrate W between a contact position at which the heater unit 6 is in contact with the substrate W and a separation position at which the heater unit 6 is separated from the substrate W
Implementation Method 2
supplying a vapor of a second organic solvent to a space between a facing surface of the heater unit 6 having the facing surface facing a lower surface of the substrate W and the lower surface of the substrate W
Implementation Method 3
A part of the IPA liquid film is evaporated and is changed into a vapor phase thereby, so that the inside of the fine pattern is filled with vapor-phase IPA
Data Source
AI summary
A substrate processing method includes a substrate holding step of horizontally holding a substrate, a substrate rotating step of rotating the substrate held horizontally around a rotational axis along a vertical direction, a liquid-film forming step of forming a liquid film of a first organic solvent that is used to process an upper surface of the substrate on the upper surface of the substrate by supplying the first organic solvent to the upper surface of the substrate held horizontally, a vapor supplying step of supplying a vapor of a second organic solvent to a space between a facing surface of a heater unit that has the facing surface facing a lower surface of the substrate held horizontally and the lower surface of the substrate, a substrate heating step of heating the substrate being in a rotational state by means of the vapor of the second organic solvent in parallel with the substrate rotating step and the liquid-film forming step, and a substrate drying step of, after the substrate heating step, excluding the liquid film of the first organic solvent from the substrate held horizontally and drying the upper surface of the substrate in a state in which the rotation of the substrate is stopped and the substrate is in contact with the heater unit.