Substrate Drying with Two-Stage Heating for Pattern Integrity
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Solution Overview
Problem
The miniaturization of patterns on substrates, such as semiconductor wafers, leads to increased aspect ratios, making them prone to pattern collapse during drying due to surface tension, even when using sublimable substances in drying processes.
Innovation Solution
A substrate drying apparatus and method that involves forming a solid film of a sublimable substance on the substrate, followed by a controlled heating process to vaporize residual liquids at a temperature below the sublimation point, then removing the solid film at or above the sublimation temperature, preventing pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sublimable substance is used to fill pattern recesses for drying, then pattern collapse due to liquid surface tension is prevented, but pattern collapse may still occur due to residual liquid vaporization pressure during heating
Solution Approach 1:
The patent applies preliminary action by performing liquid removal before sublimation. The processed surface is treated to remove processing liquid and solvent prior to heating, preventing the harmful effect of residual liquid vaporization that would cause pattern collapse. This sequential approach ensures the sublimable substance is in a dry state before thermal processing.
Solution Approach 2:
The drying process is segmented into distinct stages: liquid removal stage followed by sublimation stage. This segmentation allows each stage to be optimized independently - first removing all liquid content, then sublimating the sublimable substance without liquid interference, thereby preventing pattern collapse at each step.
2Productivity
If the substrate is heated to sublimation temperature to remove the sublimable substance, then the solid film is effectively removed, but residual liquid may vaporize and cause pattern collapse
Solution Approach 1:
The patent performs liquid removal as a preliminary action before heating to sublimation temperature. By removing processing liquid and solvent beforehand, the subsequent heating step only needs to sublime the sublimable substance without risking liquid vaporization, thus maintaining both productivity and preventing pattern collapse.
Solution Approach 2:
The patent skips the intermediate stage of heating with residual liquid present. By rushing through the liquid removal step completely before initiating heating, the process transitions directly from dry solid film to sublimation, avoiding the dangerous intermediate state where liquid vaporization could cause pattern collapse.
3Device complexity
If solvent and processing liquid are not completely removed before sublimation, then the drying process is simpler, but residual liquid causes pattern collapse during heating
Solution Approach 1:
The patent emphasizes complete liquid removal as a necessary preliminary action before sublimation. The processed surface is treated to ensure all processing liquid and solvent are removed, creating a dry state that prevents pattern collapse during subsequent heating, regardless of increased process complexity.
Solution Approach 2:
The patent applies beforehand cushioning by completely removing liquid and creating a dry state prior to heating. This preparatory measure cushions against the potential harmful effect of liquid vaporization, ensuring pattern integrity even though it requires additional processing steps.
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
Effectively prevents pattern collapse by ensuring residual liquids are vaporized before the sublimable substance film is removed, maintaining the integrity of the pattern during the drying process.
Implementation Method 1
vaporize the solvent and the processing liquid remaining in the solid film by heating the substrate, on which the solid film is formed, and maintaining the substrate at a temperature falling within a first temperature range that is lower than a sublimation temperature of the sublimable substance
Implementation Method 2
remove the solid film from the processing surface by heating the substrate to a temperature falling within a second temperature range that is equal to or higher than the sublimation temperature of the sublimable substance
Data Source
AI summary
A substrate drying apparatus, a substrate drying method and a storage medium are capable of sublimating a sublimable substance filled in recesses of a pattern formed on a substrate while preventing pattern collapse. A first unit includes a solution supplier which supplies a sublimable substance solution containing a sublimable substance and a solvent to a processing surface, and a first liquid remover which forms a solid film of the sublimable substance on the processing surface by removing the solvent and a processing liquid from the processing surface. A second unit includes a second liquid remover which vaporize the solvent and the processing liquid remaining in the solid film by heating the substrate, and maintaining the substrate at a temperature within a first temperature range, and a solid film remover which remove the solid film from the processing surface by heating the substrate at a temperature within a second temperature range.