NFT Peg-Disc Segmentation for HAMR Thermal Robustness
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Solution Overview
Problem
The thermal robustness of near-field transducers (NFTs) in heat-assisted magnetic recording (HAMR) systems is compromised due to temperature rises from laser energy, leading to degradation and reduced service life, along with issues like misshapen or recessed NFTs and contamination affecting their reliability.
Innovation Solution
The formation of NFTs with a disc and peg structure, where the peg extends towards the recording media, and the use of a barrier layer and specific materials like gold alloys and barrier layers to enhance thermal robustness, reduce variability, and improve microstructure, allowing for better alignment and higher areal densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NFTs are used in HAMR systems, then recording capability is improved, but thermal robustness deteriorates due to temperature rises from laser energy
Solution Approach 1:
The NFT is divided into two distinct components: a peg portion that extends toward the recording media and a disc portion that is optically coupled to the waveguide. This segmentation allows the peg to be positioned closer to the media for improved recording capability while the disc remains separated to reduce thermal exposure from the laser energy, thereby resolving the contradiction between recording capability and thermal robustness.
2Reliability
If NFTs operate under laser energy, then recording function is enhanced, but service life reduces due to degradation
Solution Approach 1:
The disc portion acts as an intermediary component that optically couples the waveguide to the peg while being positioned at a distance from the recording media. This intermediary structure allows laser energy to be delivered to the peg for enhanced recording function while the disc itself remains thermally isolated, reducing degradation and extending the service life of the NFT assembly.
3Use of energy by moving object
If NFTs are exposed to high temperature, then laser energy delivery is improved, but misshaping and recession occur
Solution Approach 1:
By segmenting the NFT into a peg portion and a disc portion separated by a gap, the design allows the peg to receive concentrated laser energy for effective recording while the disc remains in a cooler region. This spatial separation through segmentation prevents the misshaping and recession that would occur if the entire NFT structure were exposed to high temperatures, thereby maintaining structural integrity while enabling effective energy delivery.
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
The enhanced thermal robustness of NFTs increases their service life, reduces variability and rework, and enables higher areal densities with improved microstructure and alignment, minimizing peg-disc separation and temperature-related issues.
Implementation Method 1
forming a barrier layer adjacent at least the back edge of the rod
Implementation Method 2
polishing the deposited disc material to form a top surface substantially planar with the top of the forward rod portion
Data Source
AI summary
Methods of forming a NFT the methods including forming a hard mask positioned over at least a portion of the rod, the hard mask including at least one layer; patterning a resist mask over the hard mask, the resist mask having an edge positioned over at least a portion of the rod; etching a portion of the hard mask to expose a back edge of the rod and to form a back edge of the hard mask, wherein the back edge of the rod is equivalent to the back edge of the peg; and wherein a forward portion of the rod which is the portion of the rod forward of the back edge is covered by the hard mask; forming a disc mask including a void configured to form a disc of a NFT, the disc mask being formed over at least a portion of the hard mask so that the exposed back edge of the rod is within the void configured to form the disc; etching an area exposed in the void of the disc mask to remove both a rear portion of the rod and the surrounding dielectric up to the back edge of the hard mask edge; depositing a disc material in the etched void, wherein the back edge of the hard mask defines the front edge of the disc and the back edge of the rod is in contact with the front edge of the disc; and polishing the deposited disc material to form a top surface substantially planar with the top of the forward rod portion.