Patterned Media Fabrication via Block Copolymer Self-Assembly
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Solution Overview
Problem
Conventional methods for fabricating patterned media, such as bit-patterned magnetic recording devices, are limited in achieving different feature densities in various regions, which restricts the ability to increase data bit island density while maintaining servo feature density within lithographic resolution limits, and are not suitable for integrated circuits with non-uniform features.
Innovation Solution
A method involving a substrate with a lithographically patterned surface layer having distinct regions, where self-assembled block copolymer structures are used to achieve different feature densities by transferring patterns into an exterior layer, allowing for separate processing of data and servo regions, and using masking materials to control the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional lithography is used to increase bit density, then areal bit density can be increased up to about 0.5 Tbit/in2, but further density increase is limited by lithographic resolution limits
Solution Approach 1:
The disk surface is divided into different regions (data regions and servo regions) that can be processed separately. Data regions undergo additional block copolymer self-assembly processing to achieve high density multiplication, while servo regions maintain conventional lithographic patterns for reliable positioning and control functions.
Solution Approach 2:
Different regions of the patterned medium are given different feature densities according to their functional requirements. Data regions use block copolymer self-assembly to achieve >1 Tbit/in2 density, while servo regions maintain lower density patterns suitable for conventional lithography, allowing each region to be optimized for its specific purpose.
2Quantity of substance
If block copolymer self-assembly is applied to the entire surface, then data region density can be increased, but servo region density cannot be maintained within lithographic limits
Solution Approach 1:
The surface is segmented into data regions and servo regions with different processing treatments. A first masking material is applied to data regions to protect them during block copolymer self-assembly, while servo regions remain exposed for conventional lithographic patterning. This segmentation enables independent optimization of each region type.
Solution Approach 2:
The invention implements local quality by applying block copolymer self-assembly only to data regions where high density is needed, while maintaining conventional lithographic patterns in servo regions. This selective application allows the data regions to achieve >1 Tbit/in2 density while servo regions maintain densities suitable for reliable positioning and control.
3Quantity of substance
If block copolymer self-assembly is used to multiply areal bit density, then density can exceed 1 Tbit/in2, but the method produces uniform density across the entire surface
Solution Approach 1:
The surface is divided into data regions and servo regions with different processing treatments. A first masking material is applied to data regions to protect them during block copolymer self-assembly, while servo regions remain exposed for conventional lithographic patterning. This segmentation enables independent optimization of each region type.
Solution Approach 2:
The invention implements local quality by applying block copolymer self-assembly only to data regions where high density is needed, while maintaining conventional lithographic patterns in servo regions. This selective application allows the data regions to achieve >1 Tbit/in2 density while servo regions maintain densities suitable for reliable positioning and control.
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 the fabrication of patterned media with regions of varying feature densities, enhancing storage capabilities and performance by allowing independent control over data and servo region densities, suitable for both magnetic storage devices and integrated circuits.
Implementation Method 1
forming self-assembled block copolymer structures over the lithographically patterned surface layer, the self-assembled block copolymer structures aligning with the first pattern in the first region
Data Source
AI summary
The disclosure relates generally to a method for fabricating a patterned medium. The method includes providing a substrate with an exterior layer under a lithographically patterned surface layer, the lithographically patterned surface layer comprising a first pattern in a first region and a second pattern in a second region, applying a first masking material over the first region, transferring the second pattern into the exterior layer in the second region, forming self-assembled block copolymer structures over the lithographically patterned surface layer, the self-assembled block copolymer structures aligning with the first pattern in the first region, applying a second masking material over the second region, transferring the polymer block pattern into the exterior layer in the first region, and etching the substrate according to the second pattern transferred to the exterior layer in the second region and the polymer block pattern transferred to the exterior layer in the first region.