Substrate Drying Apparatus Using Supercritical Fluids
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Solution Overview
Problem
Conventional drying processes for semiconductor substrates with fine circuit patterns are inefficient and prone to pattern damage, especially when the line width is less than 30 nm, due to low efficiency and pattern collapse during the drying process.
Innovation Solution
A substrate drying apparatus utilizing supercritical fluids with different temperatures and pressures to effectively dry the substrate, preventing pattern collapse and reducing particle generation by using a chamber, reservoirs, and a supply unit to manage the supercritical fluids, which are heated to specific temperatures and pressures to maintain their supercritical state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional drying process using isopropyl alcohol is used, then substrate can be dried, but drying efficiency is low and pattern collapse occurs
Solution Approach 1:
The patent changes the physical parameters of the drying medium by using supercritical fluids instead of conventional isopropyl alcohol. The supercritical fluid is maintained at specific temperature and pressure conditions (temperature at or above critical point, pressure at or above critical pressure) to achieve both high drying efficiency and pattern integrity through its unique properties of high diffusivity and low surface tension
Solution Approach 2:
The patent utilizes phase transition of the drying medium by employing supercritical fluid that can transition between liquid-like and gas-like states. The supercritical fluid penetrates the substrate effectively and then transitions to gas phase for removal, enabling efficient drying without causing pattern collapse due to controlled phase change behavior
2Productivity
If drying process is performed on substrate with fine circuit patterns, then substrate can be dried, but pattern damage frequently occurs
Solution Approach 1:
The patent changes the physical parameters of the drying medium to supercritical state with temperature at or above critical point and pressure at or above critical pressure. This parameter change gives the drying medium high diffusivity for effective penetration and low surface tension to avoid pattern damage, simultaneously achieving drying capability and pattern stability
Solution Approach 2:
The patent replaces the conventional mechanical drying process (using liquid isopropyl alcohol and physical removal) with a supercritical fluid-based process. The supercritical fluid's unique properties eliminate the need for harsh mechanical drying actions that cause pattern collapse, providing both drying capability and pattern stability
3Loss of time
If supercritical fluid with temperature less than substrate temperature is used, then drying time is reduced, but particle generation may increase
Solution Approach 1:
The patent optimizes the temperature parameter of the supercritical fluid to be at or above its critical point but controlled relative to substrate temperature. This parameter optimization enables rapid drying by reducing temperature difference-driven convection time while maintaining supercritical properties that prevent particle generation through controlled fluid behavior
4Productivity
If supercritical fluid with temperature greater than substrate temperature is used, then drying efficiency is improved, but particle generation increases
Solution Approach 1:
The patent optimizes the temperature parameter of the supercritical fluid to be at or above its critical point, balancing drying efficiency with particle generation control. The supercritical state provides high diffusivity for efficient drying while the controlled temperature and pressure prevent excessive particle formation through managed fluid expansion and condensation behavior
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 apparatus reduces substrate drying time and decreases particle generation, ensuring efficient drying of semiconductor substrates without damaging fine patterns by using supercritical fluids that replace solvents and remove impurities effectively.
Implementation Method 1
A substrate drying apparatus utilizing supercritical fluids with different temperatures and pressures to effectively dry the substrate, preventing pattern collapse and reducing particle generation
Implementation Method 2
heated to specific temperatures and pressures to maintain their supercritical state
Data Source
AI summary
Disclosed are a substrate drying apparatus, a facility of manufacturing a semiconductor device, and a method of drying a substrate. The substrate drying apparatus includes a chamber that is configured to dry a substrate at a first temperature, a first reservoir that is configured to store a first supercritical fluid at a second temperature that is less than the first temperature, a second reservoir that is configured to store a second supercritical fluid at a third temperature that is greater than the first temperature, and a supply unit connected between the chamber and the first reservoir and/or second reservoir. The supply unit is configured to supply the chamber with the first supercritical fluid and second supercritical fluid.