NFT Annealing for Thermal Protrusion Control in EAMR
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Solution Overview
Problem
Conventional energy-assisted magnetic recording (EAMR) transducers face reliability issues due to thermal protrusion of the near-field transducer (NFT) components, which leads to deformation and potential contact with the recording disk, causing performance and reliability problems.
Innovation Solution
A method involving the deposition of a dielectric layer over the NFT, creating an aperture to expose the pin portion, followed by annealing at a temperature above the expected operating temperature to relieve stress and deformations, thereby reducing thermal protrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the NFT operates at elevated temperatures to achieve high coercivity medium writing, then the magnetic recording performance is improved, but the NFT material undergoes elastic and plastic deformation causing protrusion from the ABS
Solution Approach 1:
The patent applies preliminary action by performing a pre-bake process on the NFT pin portion before final assembly. This pre-bake treatment pre-compensates for the thermal expansion and deformation that will occur during high-temperature operation, allowing the NFT to maintain proper dimensional stability and prevent protrusion from the air-bearing surface when operating at elevated temperatures for high coercivity medium writing
2Shape
If the NFT material hardness is increased to reduce protrusion, then the mechanical stability is improved, but the optical efficiency of the NFT is reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the thermal and mechanical parameters of the NFT pin portion through controlled pre-baking treatment. This process modifies the internal stress distribution and dimensional parameters of the pin without changing the material composition, thereby maintaining both optical efficiency and resistance to thermal protrusion during high-temperature operation
3Stability of the object's composition
If the NFT pin material softening temperature is increased to reduce deformation, then the thermal stability is improved, but it becomes difficult to find materials that maintain both mechanical stability and optical efficiency
Solution Approach 1:
The patent applies preliminary action by performing a pre-bake treatment on the NFT pin portion before final assembly. This pre-compensates for thermal deformation that will occur during operation, allowing the use of materials with lower softening temperatures while still achieving the required dimensional stability and preventing protrusion from the air-bearing surface
Solution Approach 2:
The patent applies parameter changes by modifying the thermal history and internal stress parameters of the pin material through controlled pre-baking. This allows standard materials to achieve the required thermal stability and dimensional control without needing to find exotic materials with extremely high softening temperatures, thereby easing manufacturing constraints
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 method effectively minimizes thermal protrusion of the NFT, improving the reliability and performance of the EAMR transducer by preventing contact with the disk and maintaining mechanical stability while maintaining optical efficiency.
Implementation Method 1
A dielectric layer that substantially covers the NFT is deposited
Implementation Method 2
The EAMR transducer is annealed at a temperature greater than the expected operating temperature of the EAMR transducer
Implementation Method 3
these deformations may be due to the combination of high internal stress and softening of the NFT material
Data Source
AI summary
A method and system provide a near-field transducer (NFT) for an energy assisted magnetic recording (EAMR) transducer. The method and system include forming an NFT having a disk and a pin. A dielectric layer that substantially covers the NFT is deposited. A portion of the dielectric layer is removed such that the dielectric layer has an aperture therein. The aperture exposes the pin of the NFT. The EAMR transducer is annealed at a temperature greater than the expected operating temperature of the EAMR transducer.