Self-Assemblable Polymer Lithography Defect Reduction
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Solution Overview
Problem
Current methods for self-assembled block copolymer layers in lithography suffer from high defect rates and limited pattern persistence length, leading to increased line edge and line width roughness, which hinders their application in semiconductor manufacturing due to high Flory-Huggins parameters and restricted annealing temperatures.
Innovation Solution
A self-assemblable polymer with adjustable molecular configurations, where the Flory Huggins parameter is higher in one configuration than the other, allowing for temperature-dependent molecular rearrangement to optimize self-assembly and defect removal, featuring a method to configure the polymer between two molecular states using stimuli like radiation and temperature to achieve lower defect rates and improved pattern quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If self-assembled block copolymer layers are used in lithography, then resolution is improved, but defect rates increase and pattern persistence length is limited
Solution Approach 1:
The patent changes the chemical composition parameters of the block copolymer system by introducing a triblock copolymer (polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene) with specific molecular weights and compositions. This parameter change enables the system to achieve both high resolution and low defect rates by optimizing the self-assembly behavior through controlled chemical structure
Solution Approach 2:
The patent uses a composite material system consisting of a triblock copolymer combined with a diblock copolymer (polystyrene-block-poly(methyl methacrylate)). This composite approach allows the system to leverage the advantages of both copolymer types: the triblock provides structural stability and low defects, while the diblock enhances resolution, achieving both goals simultaneously
2Manufacturing precision
If annealing temperature is increased to improve self-assembly, then pattern quality is improved, but semiconductor processing constraints are violated
Solution Approach 1:
The patent changes the thermal parameters of the system by selecting a triblock copolymer with a glass transition temperature of -60°C and an order-disorder transition temperature of 105°C. These parameter changes enable effective self-assembly at lower annealing temperatures (below 200°C) that are compatible with semiconductor processing constraints while still achieving high pattern quality
3Stability of the object's composition
If Flory-Huggins parameter is increased to enhance phase separation, then self-assembly is improved, but line edge roughness increases
Solution Approach 1:
The patent optimizes the Flory-Huggins interaction parameter by carefully selecting the triblock copolymer composition with 20-80 wt% styrene content and specific block length ratios. This parameter optimization achieves sufficient phase separation for stable self-assembly while maintaining smooth line edges by preventing excessive interfacial tension that would cause roughness
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
This approach reduces defect levels and enhances pattern persistence length while maintaining low line edge and width roughness, enabling more effective self-assembly and annealing within semiconductor processing constraints.
Implementation Method 1
self-assemblable block copolymers are compounds useful in nanofabrication because they may undergo an order-disorder transition on cooling below a certain temperature (order-disorder transition temperature To/d) resulting in phase separation of copolymer blocks
Implementation Method 2
heating the self-assemblable polymer to a first temperature T1 above its glass transition temperature Tg
Implementation Method 3
the first monomers when in the first molecular arrangement have a lower chemical affinity for the second monomers than the first monomers when in the second molecular arrangement
Data Source
AI summary
A self-assemblable polymer is disclosed, having first and second molecular configurations with the first molecular configuration has a higher Flory Huggins parameter for the self-assemblable polymer than the second molecular configuration, and the self-assemblable polymer is configurable from the first molecular configuration to the second molecular configuration, from the second molecular configuration to the first molecular configuration, or both, by the application of a stimulus. The polymer is of use in a method for providing an ordered, periodically patterned layer of the polymer on a substrate, by ordering and annealing the polymer in its second molecular configuration and setting the polymer when it is in the first molecular configuration. The second molecular configuration provides better ordering kinetics and permits annealing of defects near its order/disorder transition temperature, while the first molecular configuration, with a higher order/disorder transition temperature, provides low line edge/width roughness for the pattern formed on setting.