Block Copolymer Nanopatterning via SiOx Conversion
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Solution Overview
Problem
Current block copolymers face challenges in controlling lateral placement and long-range ordering during self-assembly, particularly in patterning substrates at nanoscale dimensions below 50 nm, with limitations in etch resistance and propensity to form patterns everywhere on pre-patterned surfaces.
Innovation Solution
A copolymer composition comprising a poly(methyl methacrylate) block and a poly((trimethylsilyl)methyl methacrylate) block with specific molecular weight and polydispersity ranges, allowing for controlled self-assembly and conversion to an etch-resistant SiOx species, enabling precise patterning of nanostructures on silicon substrates in the 20-40 nm range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If block copolymer self-assembly is used for nanoscale patterning, then feature size below 50 nm can be achieved, but control over lateral placement and long-range ordering is difficult
Solution Approach 1:
The substrate is pre-patterned with topographic features (grooves, holes, or posts) before applying the block copolymer. This preliminary topographic guidance directs the self-assembly process, ensuring that microdomains form only in desired locations with controlled lateral placement, while achieving sub-50 nm feature sizes through the copolymer's microphase separation
Solution Approach 2:
Different regions of the substrate are given different topographic properties (grooves for one orientation, holes for another) to locally control where and how block copolymer microdomains assemble. This allows spatially selective patterning with precise lateral placement control while maintaining nanoscale feature dimensions
2Reliability
If conventional block copolymers are used for patterning, then self-assembly occurs, but etch resistance is insufficient
Solution Approach 1:
The invention uses a composite block copolymer system consisting of polystyrene-b-poly(2-methyl-2-oxazoline) that combines the self-assembly capability of block copolymers with the etch resistance of poly(2-methyl-2-oxazoline). The latter block provides superior resistance to plasma etching processes while the former enables microdomain formation, achieving both patterning reliability and etch resistance simultaneously
3Manufacturing precision
If block copolymer patterning is applied to pre-patterned surfaces, then directed self-assembly occurs, but patterns form everywhere on the surface
Solution Approach 1:
The substrate is pre-patterned with topographic features that serve as physical templates before block copolymer deposition. These pre-formed topographic structures act as confinement regions that restrict self-assembly to specific locations only, preventing unwanted pattern formation in areas without topographic guidance while enabling precise pattern positioning
Solution Approach 2:
Topographic features are selectively created in specific regions of the substrate to provide localized guidance for block copolymer assembly. This spatially differentiated approach ensures that self-assembly occurs only where topographic features exist, eliminating harmful unwanted patterns while achieving precise positional control
4Manufacturing precision
If annealing is performed to achieve self-assembly, then microdomains form, but defect formation increases
Solution Approach 1:
The invention optimizes annealing parameters including temperature (typically 100-200°C), time (1-24 hours), and atmosphere to achieve complete microphase separation without excessive thermal energy input. This controlled parameter adjustment allows microdomains to form with high periodicity while minimizing defects by avoiding thermal degradation and unwanted side reactions
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 copolymer composition achieves low defect structures and improved etch resistance, enabling efficient thermal processing and directed self-assembly of periodic nanostructures with reduced defect formation and enhanced control over feature sizes.
Implementation Method 1
treating the annealed film to remove the poly(methyl methacrylate) from the annealed film and to convert the (trimethylsilyl)methyl methacrylate in the annealed film to SiOx
Implementation Method 2
Some block copolymers, consisting of two or more distinct homopolymers joined end to end, are known self-assemble into periodic micro domains having typical dimensions of 10 nanometers to 50 nanometers (nm)
Implementation Method 3
annealing the film; wherein the block copolymer exhibits a number average molecular weight, MN, of 1 to 1,000 kg/mot and, wherein the block copolymer exhibits a polydispersity, PD, of 1 to 2
Data Source
AI summary
A copolymer composition including a block copolymer having a poly(methyl methacrylate) block and a poly((trimethylsilyl)methyl methacrylate) block is provided; wherein the block copolymer exhibits a number average molecular weight, MN, of 1 to 1,000 kg/mol; and, wherein the block copolymer exhibits a polydispersity, PD, of 1 to 2. Also provided are substrates treated with the copolymer composition.