Imprint Pattern Guided Self-Assembly for Bit-Patterned Media Templates
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Solution Overview
Problem
Unguided lamellar block copolymer directed self-assembly in bit-patterned media (BPM) stacks results in curvilinear and swirling patterns, which are not suitable for magnetic stacks that require straight lines and circular lines for magnetic material patterns, limiting the ability to fabricate high-density bit-patterned media templates.
Innovation Solution
The use of imprint pattern guided self-assembly of lamellar block copolymer on a quartz substrate, involving a resist layer deposition, descum and trim process, brush backfill for chemical contrast pattern generation, and a dry Cr lift-off process to create lamellar guiding lines, which are then etched into the substrate to produce high-density bit-patterned media templates with straight line features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If unguided lamellar block copolymer directed self-assembly is used, then the self-assembly process is simple, but the resulting patterns are curvilinear and swirling which are not suitable for BPM stacks requiring straight and circular line patterns
Solution Approach 1:
The patent introduces an intermediary guiding layer with imprinted patterns that mediates between the simple self-assembly process and the requirement for straight line patterns. The guiding layer acts as a template that directs the block copolymer assembly into linear configurations, resolving the contradiction by adding a intermediate structure that imposes geometric constraints on the self-assembly process.
Solution Approach 2:
The patent changes the parameter of pattern geometry by introducing a guiding layer with specific imprinted patterns. This parameter change transforms the unguided random self-assembly into guided directional self-assembly, enabling the formation of straight and circular line patterns suitable for BPM stacks while maintaining the self-assembly mechanism.
2Device complexity
If unguided self-assembly is used, then the process requires fewer steps, but it cannot achieve the high-density pattern transfer needed for BPM templates
Solution Approach 1:
The patent applies preliminary action by pre-imprinting patterns in the guiding layer before the block copolymer self-assembly occurs. This preliminary patterning action creates a template that directs subsequent material deposition and assembly, enabling high-density pattern transfer to be achieved through a structured multi-step process rather than relying on unguided random assembly.
3Manufacturing precision
If imprint pattern guided self-assembly with multiple process steps is used, then straight line patterns suitable for BPM are achieved, but the process complexity increases
Solution Approach 1:
The patent segments the manufacturing process into distinct functional steps: imprinting the guiding layer, depositing the block copolymer, and performing selective removal. This segmentation allows each step to be optimized independently, achieving precise linear patterns while making the overall complex process more controllable and manufacturable through modular processing stages.
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 fabrication of high-density bit-patterned media templates with straight line magnetic features, overcoming the limitations of unguided self-assembly by achieving precise pattern transfer and increasing density through directed self-assembly and etching processes.
Implementation Method 1
imprint pattern guided self-assembly of lamellar block copolymer
Implementation Method 2
etched into the substrate to fabricate a high-density bit patterned media (BPM) template
Data Source
AI summary
The embodiments disclose a method of using a trimmed imprinted resist and chemical contrast pattern to guide a directed self-assembly (DSA) of a predetermined lamellar block copolymer (BCP), creating chromium (Cr) lamellar guiding lines using the BCP and DSA in a dry Cr lift-off process and etching the Cr lamellar guiding line patterns into a substrate to fabricate the imprint template.