Perpendicular Magnetic Recording Medium Grain Projection Angle
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Solution Overview
Problem
The challenge in magnetic recording media is maintaining uniformity and HDI characteristics as pattern sizes decrease, leading to degraded signal-to-noise ratios and jitter noise due to issues in the lift-off process of fine patterns in perpendicular magnetic recording media.
Innovation Solution
A perpendicular magnetic recording medium is developed with a non-magnetic granular underlayer comprising metal grains and a grain boundary layer, where the contact angle of the projecting portion is optimized between 45° to 85°, and a self-assembled lithography method using diblock copolymers forms a micro-phase separation structure to enhance pattern uniformity and crystal orientation, improving the separation between grains and reducing pitch dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of patterns is reduced to increase recording density, then the recording density is improved, but the uniformity of patterns is deteriorated in the lift-off process
Solution Approach 1:
The invention changes the physical and chemical parameters of the grain boundary layer by controlling the contact angle between metal grains and the grain boundary material to be within 45° to 85°. This parameter optimization ensures that fine patterns can be formed with high uniformity even at reduced sizes, resolving the contradiction between increased recording density and maintained pattern uniformity
Solution Approach 2:
The invention uses a composite grain boundary layer composed of specific materials (oxides such as SiO2, Al2O3, TiO2, or nitrides such as Si3N4) that exhibit controlled wetting properties. This composite structure enables the metal grains to form projections with optimized contact angles, allowing high-density recording while maintaining pattern uniformity during the lift-off process
2Manufacturing precision
If the contact angle of projecting portion is optimized to improve pattern uniformity, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The invention employs self-assembly processes where metal grains automatically form projections with optimized contact angles (45° to 85°) on the grain boundary layer during deposition. This self-organizing behavior eliminates the need for complex external control mechanisms, achieving high pattern uniformity without significantly increasing device complexity
Solution Approach 2:
By optimizing the contact angle parameter within a specific range (45° to 85°), the invention achieves a balance between pattern uniformity and structural simplicity. This parameter optimization allows the grain boundary layer to naturally guide pattern formation without requiring additional complex structural elements
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 enhances the signal-to-noise ratio and recording reproduction characteristics by improving the separation between grains and crystal orientation, reducing jitter noise and maintaining high-density recording efficiency.
Implementation Method 1
a self-assembled lithography using diblock copolymer is a method which can form fine patterns of several nanometers to several tens of nanometers at low cost by utilizing a micro-phase separation structure (lamellar, cylindrical or spherical structure or the like), which is formed by subjecting the diblock copolymer to thermal annealing
Implementation Method 2
a self-assembled lithography using diblock copolymer is a method which can form fine patterns of several nanometers to several tens of nanometers at low cost by utilizing a micro-phase separation structure
Implementation Method 3
the contact angle of the projecting portion is optimized between 45° to 85°
Data Source
AI summary
According to one embodiment, a perpendicular magnetic recording medium is provided, which includes a non-magnetic granular underlayer formed on a substrate and containing metal grains of a first metal and a grain boundary layer surrounding the metal grains, each metal grain including a projection projecting from the boundary layer and a bottom portion embedded in the grain boundary layer, and a contact angle of the edge of the projection to the surface of the grain boundary layer being 45° to 85°, a non-magnetic intermediate layer formed on a surface of each projection and a magnetic recording layer having a projection pattern formed on the basis of a pattern of the projections in the non-magnetic intermediate layer via the non-magnetic intermediate layer.