Hydrophobic Surface Treatment for Wafer Pattern Collapse
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Solution Overview
Problem
Pattern collapse during wet clean and drying processes in semiconductor manufacturing, particularly at sub-20 nm critical dimensions, is a significant issue due to high capillary forces, and existing methods fail to adequately address the role of liquid surface tension, viscosity, substrate mechanical strength, pattern density, and aspect ratio, as well as cleaner chemistry damage.
Innovation Solution
The formation of a hydrophobic layer on semiconductor substrates using low surface tension modifying fluids, specifically compositions containing trialkylsilyl compounds and solvents, which reduce capillary forces by achieving a water contact angle of at least 50 degrees, thereby minimizing pattern collapse during drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional wet clean and drying processes are used, then cleaning effectiveness is achieved, but pattern collapse occurs due to high capillary forces
Solution Approach 1:
The patent changes the surface energy parameters of the substrate by applying a hydrophobic coating, which modifies the contact angle to at least 50 degrees. This parameter change reduces capillary forces during drying, preventing pattern collapse while maintaining cleaning effectiveness. The surface treatment alters the physical-chemical properties of the substrate surface without changing the cleaning process itself.
Solution Approach 2:
The hydrophobic coating acts as an intermediary layer between the liquid cleaning solution and the patterned substrate. This intermediate layer modifies the interaction between the liquid and substrate, reducing capillary adhesion forces that cause pattern collapse, while still allowing effective cleaning to occur.
2Manufacturing precision
If hydrophobic coating is applied to reduce capillary forces, then pattern collapse is minimized, but water contact angle increases beyond optimal range
Solution Approach 1:
The patent precisely controls the hydrophobicity parameter by specifying a contact angle range of at least 50 degrees, which is sufficient to reduce capillary forces without creating excessive hydrophobicity that would interfere with subsequent processing steps. This optimized parameter range balances pattern protection with process compatibility.
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 hydrophobic layer significantly reduces pattern collapse during semiconductor manufacturing processes, ensuring the integrity of features with dimensions as small as 20 nm by minimizing capillary forces and maintaining surface treatment layer effectiveness.
Implementation Method 1
contacting the surface with a surface treatment composition to form a surface treatment layer such that the surface treatment layer has a water contact angle of at least about 50 degrees
Implementation Method 2
low surface tension modifying fluids that impart the surfaces of a semiconductor substrate with a hydrophobic layer can minimize the capillary forces that drive pattern collapse
Implementation Method 3
the Laplace pressure is minimized when the contact angle, i.e., the angle a liquid (e.g., water) creates when in contact with a substrate surface, is at or near 90 degrees. This in combination with the presence of a low surface tension fluid can greatly reduce the forces that cause pattern collapse
Data Source
AI summary
This disclosure relates to methods and compositions for treating a wafer having a pattern disposed on a surface of the wafer.