Patterned Template Layer for Perpendicular Magnetic Recording
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Solution Overview
Problem
Current perpendicular magnetic recording (PMR) disk fabrication methods using templated growth result in undesirable grain size distribution, random grain location, and poor surface texture due to etching of template layers, leading to variations in magnetic recording properties and thermal instability.
Innovation Solution
A patterned template layer with platinum (Pt) or palladium (Pd) regions arranged in a hexagonal-close-packed pattern, where the metallic magnetic material preferentially deposits on pristine surfaces and oxide material migrates to oxidized regions, guided by chemical contrast and epitaxy, eliminating the need for etching and ensuring a planar surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If templated growth with etched template layer is used, then grain segregation is achieved, but surface texture deteriorates and planarization is required
Solution Approach 1:
The patent extracts the harmful etching process from the template layer fabrication, using self-assembled monolayers (SAMs) that provide patterned templates without requiring material removal. The SAMs are formed by spontaneous organization of molecules on the template layer surface, creating the desired pattern through self-assembly rather than destructive etching.
Solution Approach 2:
The patent changes the physical-chemical parameters of the template layer surface by introducing SAMs with specific molecular structures and orientations. The SAMs modify surface energy, wettability, and chemical reactivity parameters, enabling selective deposition of magnetic material in desired patterns without altering the underlying template layer topography.
2Ease of manufacture
If random nucleation sites are used during sputtering deposition, then deposition is simple, but grain location becomes random and uniformity deteriorates
Solution Approach 1:
The patent performs preliminary action by pre-forming self-assembled monolayers on the template layer before magnetic material deposition. These SAMs create pre-patterned nucleation sites that guide the subsequent deposition process, ensuring uniform grain locations while maintaining a relatively simple overall manufacturing process.
Solution Approach 2:
The self-assembled monolayers serve as an intermediary layer between the template layer and the magnetic material. This intermediary provides controlled nucleation sites that mediate the deposition process, directing where grains form and ensuring uniform distribution without requiring complex deposition equipment or procedures.
3Reliability
If oxide segregants are added to enhance grain segregation, then intergranular coupling is reduced, but thermal stability may be compromised
Solution Approach 1:
The patent applies local quality by creating spatially varying properties through the self-assembled monolayers. Different regions of the template layer surface are functionalized with different SAMs or SAM configurations, providing locally optimized conditions for grain formation. This allows precise control over grain segregation and intergranular coupling in specific regions without globally compromising thermal stability.
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
This approach achieves uniform grain size and distribution, improved thermal stability, and eliminates the need for planarization, resulting in enhanced magnetic recording performance and surface quality.
Implementation Method 1
the lattice orientation of the magnetic grains can be guided by the epitaxy of the regions of pristine Pt or Pd material
Implementation Method 2
The two separate regions of the template layer are characterized by markedly different surface chemistries and energies, which provide a 'chemical contrast' to impinging atoms during deposition of the magnetic material and oxide material, effectively guiding the deposition
Implementation Method 3
the oxide migrating to the oxidized Pt or Pd regions due to the matching of lower surface energy
Implementation Method 4
achieves uniform grain size and distribution
Implementation Method 5
Pt or Pd regions arranged in a hexagonal-close-packed pattern
Data Source
AI summary
A perpendicular magnetic recording (PMR) disk has a patterned template layer for the growth of the magnetic grains and the nonmagnetic material surrounding the grains. The template layer is a substantially planar platinum (Pt) or palladium (Pd) layer that is patterned to have Pt or Pd regions arranged in a hexagonal-close-packed (hcp) pattern with the Pt or Pd regions surrounded by Pt-oxide or Pd-oxide regions. The two separate regions of the template layer have different surface chemistries and energies, which provide a “chemical contrast” to impinging atoms during deposition of the metallic magnetic material and nonmagnetic (typically oxide) material, effectively guiding the deposition. The metallic magnetic material is preferentially deposited on the pristine, epitaxial Pt or Pd regions to form the magnetic grains, while the oxide migrates to the oxidized Pt or Pd regions due to the matching of lower surface energy.