Azeotropic Solvent Mixtures for Sub-50 nm Pattern Collapse Prevention
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Solution Overview
Problem
Existing methods for manufacturing integrated circuits with sub-50 nm features suffer from pattern collapse due to capillary forces during wet chemical processing, despite efforts to lower surface tension and contact angle, and fail to account for chemical reactions and elastic retraction forces.
Innovation Solution
A composition comprising an azeotropic mixture of alkanol and carboxylic acid ester is used to minimize pattern collapse, focusing on the selection of organic solvents without surfactants, which forms a homogeneous solution with low water content and supports aspect ratios up to 20 or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet chemical processing with conventional solvents is used, then manufacturing process is simple, but pattern collapse occurs due to capillary forces
Solution Approach 1:
The patent changes the physical-chemical parameters of the processing fluid by using an azeotropic solvent mixture instead of conventional water-based solvents. This mixture has different surface tension characteristics and evaporation properties that reduce capillary forces during drying, thereby preventing pattern collapse while maintaining manufacturing simplicity
Solution Approach 2:
The patent employs a composite solvent system consisting of an azeotropic mixture of organic solvents (such as isopropanol and ethyl acetate) rather than a single solvent or water-based solution. This composite fluid system provides optimized properties for reducing capillary stress on high aspect ratio patterns during the drying process
2Manufacturing precision
If surface tension of the fluid is lowered to prevent pattern collapse, then pattern stability improves, but particle and plasma etch residue removal becomes insufficient
Solution Approach 1:
The azeotropic solvent mixture modifies the chemical parameters of the processing environment to provide both mechanical support against capillary forces and adequate chemical cleaning capability. The specific solvent composition enables simultaneous achievement of pattern stability and effective removal of particles and plasma etch residues
Solution Approach 2:
The composite solvent system combines multiple organic solvents in specific proportions to achieve synergistic effects: one component provides surface tension management for pattern stability while another component ensures effective cleaning of contaminants, thus simultaneously addressing both pattern stability and defect removal requirements
3Loss of time
If conventional rinsing and spin dry processes are used, then processing time is short, but capillary forces cause bending and collapsing of high aspect ratio structures
Solution Approach 1:
The patent changes the evaporation parameters and surface tension characteristics of the rinsing fluid by using an azeotropic solvent mixture. This modification allows the fluid to evaporate or be removed with reduced capillary forces, preventing structure collapse while maintaining efficient processing timing
Solution Approach 2:
The azeotropic solvent mixture acts as an intermediary substance during the rinsing and drying process. It replaces water-based solvents and provides a transition medium that reduces harmful capillary forces while enabling effective removal of processing liquids without requiring extended processing time
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 solvent mixture effectively prevents pattern collapse in structures with high aspect ratios, maintaining stability during drying without requiring extensive drying processes.
Implementation Method 1
These structures may suffer from bending and/or collapsing, in particular, during the spin dry process, due to excessive capillary forces of the liquid or solution of the rinsing liquid deionized water remaining from the chemical rinse and spin dry processes
Implementation Method 2
the approaches focused on lowering the surface tension γ of the fluid, or increasing the contact angle of the fluid on the feature material surface, or both
Implementation Method 3
A composition comprising an azeotropic mixture of alkanol and carboxylic acid ester is used to minimize pattern collapse, focusing on the selection of organic solvents without surfactants, which forms a homogeneous solution with low water content
Data Source
AI summary
The invention relates to the use of a composition comprising a C1 to C6 alkanol and a carboxylic acid ester of formula (I) wherein R1 is selected from a C1 to C6 alkyl, which may be unsubstituted or substituted by OH or F, and -X21-[O-X22]n-H; R2 is selected from a C1 to C6 alkyl, which may be unsubstituted or substituted by OH or F, and -X21-[O-X22]n-H; X21, X22 are independently selected from C1 to C6 alkandiyl, which may be unsubstituted or substituted by OH or F; n is an integer from 1 to 5. wherein, the C1 to C6 alkanol and the carboxylic acid ester are selected so as to form an azeotropic mixture and are present in an amount from 20 % by weight below to 20 % by weight above such azeotropic mixture.