Stiction-Free Drying for High-Aspect Ratio Semiconductor Structures
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Solution Overview
Problem
Current wet cleaning techniques for semiconductor substrates with high-aspect-ratio features face challenges in preventing line stiction due to capillary forces, leading to deformation and residue issues during drying, which can damage the substrate and reduce yield.
Innovation Solution
A method involving exposure to a first solvent, followed by a second solvent, and then supercritical fluid to remove residual cleaning solutions, combined with electromagnetic energy and plasma processing to eliminate capillary forces and prevent stiction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet cleaning techniques are used to clean semiconductor substrates with high-aspect-ratio features, then cleaning effectiveness is improved, but line stiction occurs due to capillary forces during drying
Solution Approach 1:
The patent changes the physical state of the drying medium from liquid to supercritical fluid. By using supercritical carbon dioxide instead of liquid drying agents, the surface tension and capillary forces are eliminated while maintaining effective cleaning, thus resolving the line stiction problem that occurs with traditional wet cleaning methods
Solution Approach 2:
The patent utilizes phase transition of carbon dioxide from supercritical state to gaseous state for drying. The supercritical fluid penetrates high-aspect-ratio features effectively, then transitions to gas phase without forming liquid droplets, eliminating capillary forces and preventing line stiction during the drying process
2Duration of action of stationary object
If traditional drying methods are used after wet cleaning, then drying is achieved, but capillary pressure causes deformation of high-aspect-ratio structures
Solution Approach 1:
The patent changes the drying environment parameters by using supercritical fluid instead of liquid or gas drying agents. The supercritical state allows penetration into narrow features without liquid surface tension, and the subsequent gas phase transition prevents capillary pressure, thereby maintaining the shape integrity of high-aspect-ratio structures during drying
3Manufacturing precision
If cleaning liquids are used to clean substrates, then contaminant removal is improved, but residue from cleaning solution remains on substrate
Solution Approach 1:
The patent uses phase transition of supercritical carbon dioxide to gaseous state for residue-free drying. The supercritical fluid effectively removes cleaning solution residues, then transitions to gas phase without leaving any liquid residue on the substrate, solving the contamination problem associated with traditional liquid drying methods
Solution Approach 2:
The patent replaces mechanical liquid drying processes with supercritical fluid processing. Instead of using liquid evaporation or mechanical wiping that leaves residue, the supercritical fluid penetrates and removes contaminants, then transitions to gas phase for complete evaporation without residue
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 method effectively reduces or eliminates line stiction between semiconductor device features, ensuring clean and dry substrates by bypassing the liquid state during drying and using supercritical fluids' negligible surface tension, thereby enhancing substrate integrity and yield.
Implementation Method 1
exposing the surface of the substrate to a supercritical fluid to remove the second solvent disposed on the surface of the substrate
Implementation Method 2
transitioning the supercritical fluid to a gaseous state
Implementation Method 3
exposing the surface of the substrate to a supercritical fluid to remove the second solvent disposed on the surface of the substrate, and transitioning the supercritical fluid to a gaseous state
Implementation Method 4
exposing the surface of the substrate to a plasma and electromagnetic energy after exposing the substrate to a supercritical fluid
Implementation Method 5
exposing the surface of the substrate to electromagnetic energy
Data Source
AI summary
Embodiments of the present disclosure generally relate to a method of cleaning a substrate. More specifically, embodiments of the present disclosure relate to a method of cleaning a substrate in a manner that reduces or eliminates the negative effects of line stiction between semiconductor device features. In an embodiment, a method of cleaning a substrate includes exposing a substrate having high aspect ratio features formed thereon to a first solvent to remove an amount of a residual cleaning solution disposed on a surface of the substrate, exposing the surface of the substrate to a second solvent to remove the first solvent disposed on the surface of the substrate, exposing the surface of the substrate to a supercritical fluid to remove the second solvent disposed on the surface of the substrate, and exposing the surface of the substrate to electromagnetic energy.