HAMR Write Pole Heat Channel Adhesion Against Delamination
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) write heads, materials used for heat channels to dissipate heat from the write pole can cause undesired diffusion, affecting magnetic properties and leading to delamination, which reduces heat transfer efficiency.
Innovation Solution
A diffusion barrier layer is applied to prevent material interdiffusion, and an adhesion layer with similar thermal expansion properties is used to maintain adhesion and prevent delamination, along with a seed layer for stable heat channel formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat channel is abutted to the write pole tip to conduct heat away, then heat transfer efficiency is improved, but material interdiffusion between the write pole tip and heat channel occurs, affecting magnetic properties
Solution Approach 1:
A diffusion barrier layer is introduced between the heat channel and the write pole tip to prevent material interdiffusion while allowing thermal conduction. This intermediary layer resolves the contradiction by blocking atomic diffusion paths while maintaining thermal contact, thus preserving both heat transfer efficiency and material composition stability.
2Temperature
If the heat channel is exposed to elevated temperatures, then heat conduction function is improved, but delamination of the heat channel occurs, reducing reliability
Solution Approach 1:
An adhesion layer is positioned between the heat channel and the diffusion barrier layer to prevent delamination during thermal cycling. This intermediary layer acts as a buffer that accommodates thermal expansion differences and maintains structural integrity under elevated temperature conditions.
Solution Approach 2:
The adhesion layer is specifically selected with a coefficient of thermal expansion within 50% of the diffusion barrier layer and heat channel materials. This parameter matching reduces thermal stress during temperature cycling, preventing delamination and maintaining reliability while allowing effective heat conduction.
3Stability of the object's composition
If multiple layers are added between the write pole tip and heat channel to prevent diffusion and delamination, then material stability and adhesion are improved, but device complexity increases
Solution Approach 1:
The diffusion barrier layer serves multiple functions: it prevents material interdiffusion between the write pole tip and heat channel, provides a substrate for the adhesion layer, and maintains thermal contact. This multi-functionality reduces the need for additional separate layers, managing device complexity while ensuring material stability.
Solution Approach 2:
The write head employs a composite layered structure consisting of the diffusion barrier layer and adhesion layer, where each layer is made of specific materials selected for their properties. This composite approach allows each layer to contribute its specialized function (diffusion prevention and adhesion) while working together as an integrated system, balancing complexity with performance.
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 solution effectively prevents delamination and maintains heat transfer efficiency by ensuring compatibility and stability of the heat channel components during elevated temperatures, enhancing the performance of HAMR write heads.
Implementation Method 1
a diffusion barrier layer disposed between the write pole tip and the heat channel, the diffusion barrier layer configured to substantially prevent interdiffusion of materials between the write pole tip and the heat channel
Implementation Method 2
the adhesion layer has a coefficient of thermal expansion that is within 50% of the coefficient of thermal expansion of the diffusion barrier layer and/or the heat channel
Implementation Method 3
a heat channel abutted to at least the write pole tip of the write pole and configured to conduct heat away from the media-facing surface
Implementation Method 4
annealing magnetic write head after forming the heat channel to thereby increase heat conduction properties of the heat channel
Data Source
AI summary
Described are write head constructions that may be useful in magnetic recording, and in particular for heat-assisted magnetic recording. Such write head constructions include a heat channel abutted to the write pole to facilitate transferring heat away from the write pole and other components near the media-facing surface of the write head. To help prevent diffusion of materials between the heat channel and the write pole, a diffusion barrier layer is provided. Properties such as thermal expansion mismatch, the presence of oxide in the diffusion barrier layer, and so forth, may lead to undesired delamination of the heat channel during fabrication of the write head and/or during operation. In accordance with the present disclosure, an adhesion layer may be provided between the diffusion barrier layer and the heat channel to improve adhesion of the heat channel and effectively reduce delamination.