Block Copolymer Orientation Control via Surface Active Polymer
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Solution Overview
Problem
High-chi block copolymers with sub-10 nm half-pitch feature sizes face challenges in achieving perpendicularly oriented domains due to increased surface energy mismatch, requiring complex top-coat based orientation control strategies, which are not top-coat free and add integration complexity in standard lithography processes.
Innovation Solution
A composition comprising a block copolymer with a polycarbonate block and a surface active polymer (SAP) dissolved in a solvent, where the SAP has a high fluorinated repeat unit and a non-fluorinated hydrogen-bond donating repeat unit, allowing for non-covalent association and self-assembly to form perpendicularly oriented domain patterns without a top-coat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-chi block copolymers are used to achieve smaller feature sizes, then manufacturing precision is improved, but device complexity increases due to required top-coat based orientation control strategies
Solution Approach 1:
The patent removes the top-coat layer from the processing workflow by incorporating orientation control functionality directly into the block copolymer structure through side chains, thereby eliminating the need for separate top-coat application steps while maintaining perpendicular domain orientation
Solution Approach 2:
The orientation control capability is built into the block copolymer structure in advance through specifically designed side chains that provide neutral wetting properties, allowing perpendicular orientation to occur naturally during self-assembly without requiring subsequent top-coat processing steps
2Manufacturing precision
If top-coat based orientation control strategies are employed to achieve perpendicular orientation, then manufacturing precision is improved, but ease of operation deteriorates due to additional process complexity
Solution Approach 1:
The patent combines the orientation control function previously performed by a separate top-coat layer with the block copolymer structure itself through the incorporation of neutral wetting side chains, merging multiple functions into a single material component and simplifying the overall process
3Ease of manufacture
If neutral underlayer properties are used alone for high-chi block copolymers, then ease of manufacture is improved, but manufacturing precision deteriorates due to parallel orientation of domains
Solution Approach 1:
The patent introduces local chemical functionality through side chains attached to the block copolymer backbone, creating localized neutral wetting properties at the polymer-air interface that specifically guide perpendicular orientation without affecting the overall simplicity of the underlayer system
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
Enables perpendicularly oriented lamellar domains with sub-10 nm feature sizes without additional process complexity, improving the integration of high-chi block copolymers into standard lithography processes by using a surface active polymer to control orientation and surface energy.
Implementation Method 1
the SAP is preferentially soluble in the polycarbonate domain, allowing for non-covalent association and self-assembly to form perpendicularly oriented phase-separated domains
Implementation Method 2
allowing for non-covalent association and self-assembly to form perpendicularly oriented phase-separated domains without a top coat
Data Source
AI summary
A film layer comprising a high-chi (χ) block copolymer for self-assembly and a surface active polymer (SAP) was prepared on a substrate surface that was neutral wetting to the domains of the self-assembled block copolymer. The block copolymer comprises at least one polycarbonate block and at least one other block (e.g., a styrene-based block). The SAP comprises a hydrophobic fluorinated first repeat unit and a non-fluorinated second repeat unit bearing at least one pendent OH group present as an alcohol or acid (e.g., carboxylic acid). The film layer, whose top surface has contact with an atmosphere, self-assembles to form a lamellar or cylindrical domain pattern having perpendicular orientation with respect to the underlying surface. Other morphologies (e.g., islands and holes of height 1.0Lo) were obtained with films lacking the SAP. The SAP is preferentially miscible with, and lowers the surface energy of, the domain comprising the polycarbonate block.