Magnetic Head Pole Layer Manufacturing via Dry Etching
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in forming high-quality pole layers in narrow grooves, leading to defects like key holes and degraded write characteristics due to rough seed layers and columnar crystals, which affect recording density and overwrite properties.
Innovation Solution
A method involving the formation of a pole-layer-encasing layer with an initial nonmagnetic layer by physical vapor deposition, followed by dry etching to widen the groove and smooth the surface, allowing for the deposition of a high-quality pole layer using physical vapor deposition or plating, with alternating magnetic films and nonmagnetic layers to control thickness and residual magnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the track width is reduced to achieve higher recording density, then recording density is improved, but write characteristics such as overwrite property suffer degradation
Solution Approach 1:
The patent changes the geometric parameters of the pole layer, specifically reducing the neck height (length of track width defining portion) to optimize the magnetic field distribution. This parameter adjustment allows achieving better overwrite property while maintaining reduced track width for high recording density
Solution Approach 2:
The patent employs composite material structures including alternating magnetic films (e.g., CoFeB, CoFe) and nonmagnetic layers (e.g., Ru, Ta) to form the pole layer. This composite structure enables precise control of magnetic properties and thickness, achieving both high recording density and improved write characteristics
2Ease of manufacture
If physical vapor deposition is used to form the pole layer in a narrow groove, then manufacturing process is simplified, but defects like key holes and columnar crystals occur leading to degraded crystal quality
Solution Approach 1:
The patent introduces a nonmagnetic layer (e.g., Ru, Ta) as an intermediary between the groove and the magnetic pole layer. This intermediary layer prevents direct contact between the magnetic material and the groove walls, eliminating key hole defects and columnar crystal formation while maintaining the simplicity of physical vapor deposition
Solution Approach 2:
The patent performs preliminary actions by first forming the nonmagnetic layer in the groove before depositing the magnetic pole layer. This preliminary step prepares the surface to prevent defects during subsequent magnetic layer deposition, ensuring high crystal quality without complex manufacturing processes
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 method enables the formation of a pole layer with improved crystal quality and saturation flux density, reducing defects and enhancing write characteristics such as overwrite property and recording density.
Implementation Method 1
forming an initial nonmagnetic layer in the groove of the pole-layer-encasing layer by physical vapor deposition
Implementation Method 2
etching a surface of the initial nonmagnetic layer by dry etching so that the initial nonmagnetic layer becomes the nonmagnetic layer
Implementation Method 3
allowing for the deposition of a high-quality pole layer using physical vapor deposition or plating
Implementation Method 4
allowing for the deposition of a high-quality pole layer using physical vapor deposition or plating
Implementation Method 5
with alternating magnetic films and nonmagnetic layers to control thickness and residual magnetization
Data Source
AI summary
A method of manufacturing a magnetic head includes the steps of: forming a pole-layer-encasing layer having a pole-layer-encasing section; and forming a pole layer in the pole-layer-encasing section. The pole layer includes a first layer, and a second layer formed thereon. The step of forming the pole layer includes the steps of: forming an initial first layer by physical vapor deposition; etching the surface of the initial first layer by dry etching so that the initial first layer becomes the first layer; and forming the second layer on the first layer.