Block Copolymer Self-Assembly for BPM Master Template Fabrication
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Solution Overview
Problem
Overlay misalignments during the fabrication of bit patterned media (BPM) disk master-templates using nano-imprint lithography lead to inaccuracies in creating high-density patterns, particularly in combining data and servo patterns.
Innovation Solution
A self-aligned fully integrated stack fabrication method that avoids overlay steps by using low-frequency guiding patterns etched into an imprint substrate, allowing for simultaneous creation of high-frequency data and servo fields through guided self-assembly, ensuring accurate integration of servo information into the stack fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If overlay processes are used to combine data and servo patterns, then pattern integration is achieved, but overlay misalignments cause inaccuracies in master templates
Solution Approach 1:
The patent merges the data pattern and servo pattern fabrication into a single integrated process using block copolymer self-assembly. The block copolymer system simultaneously forms both pattern types without requiring separate overlay steps, eliminating misalignment issues while achieving complete pattern integration in one manufacturing process
Solution Approach 2:
The block copolymer system performs self-alignment through its inherent micelle formation and phase separation properties. The polymer chains automatically organize into the correct spatial arrangement of data and servo patterns without external alignment assistance, achieving self-aligned fabrication that eliminates overlay errors
2Quantity of substance
If self-assembly processes are used to create high density patterns, then pattern density is improved, but overlay misalignments still occur when combining multiple patterns
Solution Approach 1:
The block copolymer acts as an intermediary material that translates the master template features into high-density self-assembled patterns. The polymer's micelle formation process serves as a mediation step that multiplies pattern density while the self-aligned nature of micelle formation preserves alignment accuracy when combining multiple pattern types
Solution Approach 2:
The patent changes the physical and chemical parameters of the fabrication process by using block copolymer phase separation and micelle formation. This parameter change enables simultaneous high-density pattern formation with inherent self-alignment, achieving both high quantity of patterns and high precision alignment
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 method enables the production of highly accurate fully integrated stack fabrication master templates with reduced inaccuracies, effectively planarizing and encoding servo information, thus enhancing the precision and reliability of bit-patterned media fabrication.
Implementation Method 1
Self-assembly processes create regular patterns such as hexagonal close packed or square structures used for creating BPM data-patterns
Implementation Method 2
The remaining portions of the high density structures and etched image layer form a mask for an etching process
Data Source
AI summary
Provided herein is a method, including etching a first pattern into a mask, wherein the first pattern includes a first set of features corresponding to features of an imprint template; forming a second set of features over and in-between the first set of features by directed self-assembly of a block copolymer composition, wherein the first and second sets of features combine to form a second pattern; and etching the second pattern into a substrate.