Supercritical Fluid Recycling Unit for Semiconductor Substrate Drying
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Solution Overview
Problem
Conventional drying processes for semiconductor substrates, especially those with fine circuit patterns, face inefficiencies and pattern damage due to the use of isopropyl alcohol, leading to unsuitable drying for devices with line widths of 30 nm or less, necessitating a more effective method for substrate drying.
Innovation Solution
A substrate treating apparatus that utilizes a supercritical fluid to dissolve organic solvents from substrates and includes a recycling unit with a separator, distiller, heating unit, and condensation unit to recover and recycle high-purity supercritical fluids, effectively reducing organic solvent concentrations and improving drying efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If isopropyl alcohol is used for drying substrates with fine circuit patterns, then the drying process can be performed, but pattern collapse occurs and drying efficiency is reduced
Solution Approach 1:
The patent changes the physical state parameters of the drying fluid from liquid (isopropyl alcohol) to supercritical fluid (carbon dioxide at supercritical temperature and pressure). This parameter change eliminates surface tension effects that cause pattern collapse while maintaining effective drying capability, thus resolving the contradiction between drying efficiency and pattern integrity
Solution Approach 2:
The patent utilizes the phase transition characteristics of carbon dioxide between supercritical and gaseous states. By controlling temperature and pressure, the fluid transitions to a supercritical state for drying, then expands to gas for easy removal. This phase transition enables effective drying without the harmful effects of liquid surface tension on fine patterns
2Productivity
If supercritical fluid is used to dissolve organic solvents from substrates, then drying efficiency is enhanced, but organic solvent contamination accumulates in the fluid
Solution Approach 1:
The patent implements a separation system that discards organic solvents from the supercritical fluid through a separator unit. The separated fluid is then recovered and recycled back to the drying chamber, while the organic solvent is removed. This resolves the contradiction by maintaining fluid purity through continuous separation and recovery
Solution Approach 2:
The patent utilizes parameter changes (temperature and pressure adjustments) to control the solubility and phase behavior of the supercritical fluid. By adjusting these parameters in the separator unit, organic solvents are selectively removed from the fluid, enabling purity recovery while maintaining the fluid's drying effectiveness
3Productivity
If supercritical fluid is discharged after use, then the drying process is complete, but the fluid is lost and cannot be reused
Solution Approach 1:
The patent implements a continuous recycling system where the supercritical fluid is continuously recovered, separated from contaminants, and fed back to the drying chamber. This continuous circulation eliminates fluid loss and maintains constant drying efficiency, resolving the contradiction between process efficiency and fluid conservation
Solution Approach 2:
The patent recovers the supercritical fluid from the discharge stream through a separator that removes organic solvents. The recovered pure fluid is then reused in the drying process, eliminating fluid loss while maintaining process efficiency through continuous 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 apparatus enables efficient drying of substrates with fine circuit patterns by recycling high-purity supercritical fluids, reducing the risk of pattern damage and enhancing the overall drying process, thereby improving semiconductor manufacturing yields.
Implementation Method 1
a drying chamber in which an organic solvent remaining on a substrate is dissolved by using a fluid that is provided as a supercritical fluid to dry the substrate
Implementation Method 2
a heating unit heating a fluid containing an organic solvent having a second concentration discharged from the distiller, the heating unit supplying an evaporated fluid containing an organic solvent having a third concentration into the distiller
Implementation Method 3
a condensation unit liquefying a fluid containing an organic solvent having a fourth concentration discharged from the distiller
Implementation Method 4
a separator for separating the organic solvent from the fluid discharged from the drying chamber to recycle the fluid
Data Source
AI summary
The substrate treating apparatus includes a drying chamber in which an organic solvent remaining on a substrate is dissolved by using a fluid, and a recycling unit including a separator for separating the organic solvent from the fluid discharged from the drying chamber to recycle the fluid. The separator includes a distiller in which a fluid containing an organic solvent having a first concentration is introduced, a heating unit heating a fluid containing an organic solvent having a second concentration discharged from the distiller, and supplying an evaporated fluid containing an organic solvent having a third concentration into the distiller, and a condensation unit liquefying a fluid containing an organic solvent having a fourth concentration discharged from the distiller. The organic solvent has the second concentration, the first concentration, the third concentration, and the fourth concentration which are successively lowered in concentration.