Circumferentially Aligned Features for Patterned Recording Media

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Solution Overview

Problem

The creation of complex servo patterns in hexagonal and rectangular bit-patterned media is challenging, particularly due to limitations in skew angle and the difficulty in forming patterns with lamella-forming block copolymer directed self-assembly.

Innovation Solution

An apparatus and method for patterned recording media that includes a data region and a servo region with features such as rhomboidal protrusions, where the features are circumferentially aligned according to concentrically circular lines, allowing for the creation of complex servo patterns and overcoming skew angle limitations through template fabrication techniques like nanoimprint lithography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If asymmetric arrangements are used to overcome skew angle limit, then skew angle flexibility is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveskew angle flexibilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The manufacturing process is segmented into two distinct stages: first forming concentric circular lines, then forming radial lines that intersect the circular lines. This segmentation allows independent optimization of each pattern element, enabling flexible skew angle adjustments in the final asymmetric arrangement without compounding manufacturing difficulties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The concentric circular lines are formed first as a preliminary structure before the radial lines are added. This preliminary action establishes a reference framework that simplifies subsequent radial line formation and enables precise control over the final asymmetric pattern geometry and skew angle.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If complex servo patterns are created in hexagonal and rectangular BPM, then servo pattern complexity is improved, but registration difficulty increases

Engineering Contradiction:

Improveservo pattern complexityVSAvoidregistration difficulty

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The invention intentionally introduces asymmetry through the combination of concentric circular lines and radial lines, where the radial lines intersect the circular lines at specific angles to create asymmetric servo patterns. This asymmetric design enables complex servo functionality while the systematic formation method maintains registration precision.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The concentric circular lines serve as an intermediary structure that mediates between the manufacturing process and the final servo pattern. By first creating the circular lines and then adding radial lines, the invention creates a systematic intermediate framework that simplifies the formation of complex asymmetric servo patterns while maintaining precise registration.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8941938B1Apparatus and methods for circumferentially aligned features

Publication Date: 2015.01.27 SEAGATE TECH LLC

AI summary

Provided herein is an apparatus, including a first region corresponding to a data region in a patterned recording medium; a first set of features in the first region; a second region corresponding to a servo region in a patterned recording medium; and a second set of features in the second region including rhomboidal protrusions, wherein the first set of features and the second set of features are circumferentially aligned in accordance with concentrically circular lines etched into the apparatus across the first region and the second region.