Ammonia-Activated Siloxane Rinse for Sub-50nm Pattern Collapse
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Solution Overview
Problem
Current methods for manufacturing integrated circuits and other precision devices with patterned material layers of 50 nm or below suffer from pattern collapse due to capillary forces during chemical rinse and spin dry processes, especially for high aspect ratio structures.
Innovation Solution
A non-aqueous composition comprising an organic protic solvent and an ammonia-activated siloxane-type additive is used to prevent pattern collapse, specifically designed for substrates with line-space dimensions of 50 nm or less and high aspect ratios, which includes a kit with ammonia dissolved in an organic protic solvent and an H-silane additive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet chemical processing with aqueous rinse solutions is used, then particle removal and plasma etch residue removal are effective, but capillary forces during spin dry cause pattern collapse in high aspect ratio structures
Solution Approach 1:
The invention changes the physical-chemical parameters of the rinse solution by using non-aqueous solvents (isopropanol, ethyl carbonate, dimethyl sulfoxide, hexane) instead of water. This parameter change fundamentally alters the capillary forces and surface tension characteristics, preventing pattern collapse while maintaining effective particle and residue removal capabilities.
Solution Approach 2:
The invention introduces siloxane-type surfactants as intermediary substances that mediate between the patterned structures and the non-aqueous rinse solution. These surfactants modify the surface properties and interfacial tensions, enabling effective cleaning while preventing capillary-induced pattern collapse during the drying process.
2Productivity
If dimension shrinkage is continued to achieve smaller features, then device density and integration are improved, but particle and etch residue removal becomes more critical and difficult
Solution Approach 1:
The invention changes the chemical composition parameters of the rinse solution by employing non-aqueous solvents with different dielectric constants, viscosity, and surface tension properties compared to water. These parameter changes enhance the ability to remove particles and plasma etch residues from sub-50 nm features while preventing pattern collapse, thereby maintaining manufacturing precision at higher integration densities.
3Manufacturing precision
If conventional siloxane surfactants are used in aqueous solutions, then some pattern collapse prevention is achieved, but sub 50 nm structures still suffer from high pattern collapse rates
Solution Approach 1:
The invention fundamentally changes the solvent parameter from aqueous to non-aqueous (isopropanol, ethyl carbonate, dimethyl sulfoxide, or hexane), which alters the capillary pressure, surface tension, and evaporation characteristics. This parameter change, combined with siloxane-type surfactants, provides superior pattern collapse prevention for sub-50 nm structures compared to conventional aqueous systems.
Solution Approach 2:
The invention creates a composite rinse solution system combining non-aqueous solvents with siloxane-type surfactants. This composite formulation synergistically combines the low capillary pressure of non-aqueous solvents with the surface-active properties of siloxanes, achieving enhanced pattern collapse resistance that neither component achieves alone in aqueous systems.
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 composition effectively prevents pattern collapse during chemical rinse and spin dry processes, maintaining the integrity of high aspect ratio structures without using aqueous solvents, thus ensuring defect-free patterned structures in integrated circuits and other precision devices.
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 modified surface should have a contact angle in a range from about 70 degrees to about 110 degrees
Data Source
AI summary
Described herein is a non-aqueous composition including (a) an organic protic solvent, (b) ammonia, and (c) at least one additive of formulae I or IIwhereR1 is HR2 is selected from H, C1 to C10 alkyl, C1 to C10 alkoxy, C6 to C10 aryl, and C6 to C10 aroxy,R3 is selected from R2,R4 is selected from C1 to C10 alkyl, C1 to C10 alkoxy, C6 to C10 aryl, and C6 to C10 aroxy,R10, R12 are independently selected from C1 to C10 alkyl and C1 to C10 alkoxy,m is 1, 2 or 3, andn is 0 or an integer from 1 to 100.