Polymer Brush Reflow for Directed Self-Assembly Nanopatterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current directed self-assembly methods face challenges in achieving pattern dimensions of ten nanometers or less due to difficulties in producing chemically modified pre-pattern surfaces and polymer brush grafting issues, which result in weak chemical contrast and defects in nanoscale features.
Innovation Solution
The method involves selective polymer grafting using a polymer brush reflow process to create chemical contrast patterns, where a polymer brush is deposited on a structured pattern, annealed at different temperatures to graft only into trenches, and then used with block copolymers to form aligned structures with dimensions smaller than the original pattern, enabling nanoimprint masters for high-density storage and integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional directed self-assembly methods are used to form nanoscale patterns, then pattern formation is achieved, but pattern dimensions of ten nanometers or less cannot be achieved due to weak chemical contrast and polymer brush grafting issues
Solution Approach 1:
The patent applies parameter changes by implementing a two-stage thermal annealing process with different temperature ranges and durations. The first anneal at 80-120°C for 1-24 hours initiates controlled polymer brush reflow, while the second anneal at 120-180°C for 1-12 hours completes the grafting process. This staged parameter adjustment enables precise control over polymer brush morphology and chemical contrast, achieving the required pattern dimensions of 10 nm or less
Solution Approach 2:
The patent applies preliminary action by performing a first annealing step before the second annealing step. The initial anneal at lower temperature pre-processes the polymer brush layer, creating preliminary reflow that prepares the system for the subsequent higher-temperature anneal. This sequential preparation ensures optimal conditions for achieving strong chemical contrast and defect-free nanoscale patterns
2Reliability
If polymer brush is deposited on structured pattern to create chemical contrast, then chemical contrast is improved, but polymer brush grafting issues result in defects in nanoscale features
Solution Approach 1:
The patent uses parameter changes by controlling annealing temperature and time to optimize polymer brush grafting. The specific temperature ranges (80-120°C for first anneal, 120-180°C for second anneal) and durations (1-24 hours, then 1-12 hours) are carefully selected to achieve complete grafting without creating defects, thereby simultaneously improving chemical contrast and nanoscale feature quality
Solution Approach 2:
The patent applies continuity of useful action by implementing a continuous two-stage annealing process rather than a single discrete step. The first and second annealing steps are sequential and complementary, with the second anneal building upon the work done in the first. This continuous thermal processing ensures complete and uniform polymer brush grafting across the entire structured pattern, eliminating gaps or incomplete regions that would create defects
3Productivity
If block copolymer layer is deposited to form aligned structures, then pattern density is increased, but process complexity increases due to multiple annealing steps
Solution Approach 1:
The patent applies merging by combining the polymer brush deposition and annealing process with the block copolymer self-assembly process into an integrated workflow. The polymer brush preparation (including both annealing steps) is performed immediately before block copolymer deposition, creating a unified process flow that achieves high pattern density while managing complexity through systematic integration rather than separate isolated steps
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 allows for the production of nanostructures with dimensions as small as ten nanometers, enhancing storage densities and feature sizes in bit-patterned media and integrated circuits, effectively addressing the limitations of existing DSA techniques.
Implementation Method 1
The polymer brush is annealed at a first temperature and then again at a second temperature where the second temperature is higher than the first temperature
Implementation Method 2
The polymer brush is annealed at a first temperature and then again at a second temperature where the second temperature is higher than the first temperature
Implementation Method 3
aligned first block structures and second block structures are formed on the structured pattern and polymer brush
Data Source
AI summary
A method comprises forming a first structured pattern having a first line width on a substrate. A polymer brush is deposited on the structured pattern, which is annealed a first time at a first temperature and then annealed a second time at a second temperature higher than the first temperature. A block copolymer is deposited on the structured pattern and polymer brush, and aligned first block and second block structures are formed on the structured pattern and polymer brush. The first block structures and portions of the polymer brush and the structured pattern positioned beneath the first block structures are removed, and the substrate between the second block structures is exposed. The second block structures are then removed to form a second structured pattern in the substrate having a second line width, the second line width being smaller than the first line width.