Supercritical Carbon Dioxide Substrate Drying System
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Solution Overview
Problem
Conventional drying processes for semiconductor substrates face challenges in removing water from narrow gaps between patterns, leading to pattern collapse and inefficiencies, especially in sub-30 nm devices, due to difficulties in mixing non-polar organic solvents with polar water.
Innovation Solution
A substrate treating system and method utilizing supercritical carbon dioxide to dry the substrate, where the carbon dioxide is maintained in a supercritical state within a controlled chamber to efficiently remove organic solvents from gaps between patterns, leveraging its high diffusion coefficient and low surface tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional drying processes using heated nitrogen gas or liquid organic solvent are used, then the drying process can be performed, but it is difficult to remove pure water from narrow gaps between patterns, leading to pattern collapse
Solution Approach 1:
The patent changes the physical parameters of the drying medium by using supercritical carbon dioxide (temperature above 31.1°C and pressure above 73.8 atm) instead of conventional gases or liquids. This parameter change allows the CO2 to penetrate narrow gaps effectively while providing sufficient drying power, resolving the contradiction between pattern integrity and drying efficiency
Solution Approach 2:
The patent utilizes the phase transition properties of carbon dioxide between supercritical and gaseous states. The CO2 is supplied in supercritical state for effective penetration and drying, then transitions to gaseous state for easy removal, achieving both thorough drying and pattern protection without collapse
2Quantity of substance
If liquid organic solvent is supplied for a long time to replace pure water, then the solvent can replace water, but it requires supplying a large amount of liquid organic solvent, increasing process complexity
Solution Approach 1:
The patent changes from liquid organic solvent to supercritical carbon dioxide, altering the physical state and chemical properties of the drying medium. This parameter change eliminates the need for large quantities of solvent and simplifies the process by avoiding solvent mixing issues and removal steps
Solution Approach 2:
The patent uses supercritical carbon dioxide as an intermediary substance that can effectively replace water without the mixing problems of non-polar solvents. The CO2 acts as a mediator that penetrates the water-containing structures, replaces the water, and then can be easily removed by pressure reduction
3Reliability
If supercritical carbon dioxide is supplied into the chamber, then the carbon dioxide can be directly changed from gas state to supercritical state, but temperature and pressure of the chamber must be maintained
Solution Approach 1:
The patent utilizes the phase transition of carbon dioxide from gaseous to supercritical state through controlled pressure and temperature changes. This phase transition enables efficient water replacement while the system recovers energy by reducing pressure to return CO2 to gaseous state for recycling
Solution Approach 2:
The patent implements a recovery system where carbon dioxide is not discarded after use but recovered by pressure reduction and recycling. This approach reduces energy consumption by avoiding continuous supply of fresh CO2 and minimizes waste, addressing the energy concern while maintaining reliable phase change operation
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 use of supercritical carbon dioxide enables effective drying of semiconductor substrates, preventing pattern collapse and improving process efficiency by quickly replacing organic solvents and reducing the burden on the drying process, while being environmentally friendly and cost-effective.
Implementation Method 1
leveraging its high diffusion coefficient
Implementation Method 2
low surface tension
Implementation Method 3
Temperature and pressure of the chamber may be maintained to allow carbon dioxide to be directly changed from a gas state to a supercritical state
Data Source
AI summary
Disclosed are systems and methods for treating a substrate. The method may include supplying supercritical carbon dioxide into a chamber to treat a substrate. Here, temperature and pressure of the chamber is maintained to allow carbon dioxide to be directly changed from a gas state to a supercritical state when the carbon dioxide is supplied into the chamber.