Perpendicular Magnetic Head Ru Electrode Film Width Control
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Solution Overview
Problem
In perpendicular recording magnetic heads, achieving high accuracy in controlling the width of the main magnetic pole film is challenging, and there is a need to prevent the 'pole erase' phenomenon while maintaining high overwrite characteristics, which existing technologies struggle to address effectively.
Innovation Solution
A magnetic head structure is developed where the main magnetic pole film is formed within a recess in an insulating film, with an electrode film including a Ru film adhered to the recess's inner wall and a conductive magnetic film on top, allowing for precise control of the film width and crystal orientation, enhancing soft magnetic properties and reducing coercive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the main magnetic pole film width is reduced to increase track density, then recording density is improved, but manufacturing precision and yield control become significantly more difficult
Solution Approach 1:
The patent transitions from controlling magnetic pole film width through planar photolithography to controlling it through vertical recess depth and shape. By forming the magnetic pole film within a recess structure, the width is determined by the recess geometry rather than direct surface patterning, enabling more precise width control at smaller dimensions.
Solution Approach 2:
The recess structure is formed in advance before depositing the magnetic pole film. This preliminary formation of the recess cavity provides a pre-defined geometric constraint that guides the subsequent film deposition process, ensuring precise width control without relying solely on final film patterning steps.
2Reliability
If high saturation magnetic flux density materials are used in the main magnetic pole film to improve overwrite characteristics, then recording performance is enhanced, but the coercive force increases causing pole erase phenomenon
Solution Approach 1:
The patent changes the crystallographic orientation parameter of the magnetic pole film from conventional orientations to (110) orientation. This parameter change in crystal structure fundamentally alters the magnetic anisotropy, enabling the film to achieve both high saturation magnetic flux density and low coercive force, thus resolving the contradiction between overwrite performance and pole erase prevention.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers including Ru film, FeCo alloy film with specific crystal orientation, and other functional layers. This composite material system combines the high saturation flux density properties of FeCo with the low coercive force characteristics achieved through crystal orientation control and interface engineering, simultaneously achieving high overwrite capability and pole erase resistance.
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 structure enables accurate control of the main magnetic pole film width, improves overwrite characteristics, and effectively prevents the pole erase phenomenon, leading to enhanced recording density and stability in magnetic recording.
Implementation Method 1
the Ru film is adhered to an inner wall surface of the recess or a surface of a second non-magnetic film adhered thereto, thereby following a shape of the inner wall surface of the recess
Implementation Method 2
The magnetic pole film is constituted by a plated film formed by electroplating on an electrode film intended to function as a seed film
Data Source
AI summary
The present invention relates to a perpendicular recording magnetic head. A main magnetic pole film includes an electrode film and a plated magnetic film. The electrode film includes a Ru film and a conductive magnetic film, and the Ru film, which follows the shape of an inner wall surface of a recess formed in a first non-magnetic film, is adhered to the inner wall surface of the recess or a surface of a second non-magnetic film adhered thereto. The conductive magnetic film is adhered to a surface of the Ru film, thereby following the shape of the inner wall surface of the recess. The plated magnetic film is disposed adjacent the conductive magnetic film, thereby filling up the recess.