Perpendicular Magnetic Write Head Pole Inclined Face Precision
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Solution Overview
Problem
Existing methods for manufacturing perpendicular magnetic write heads struggle to achieve high precision in the formation of main magnetic pole layers, which limits recording density and performance due to difficulties in controlling the dimension and angle of inclined faces.
Innovation Solution
A method involving the formation of a main magnetic pole layer with an inclined part and a flat part, using a stack structure with different nonmagnetic layers where the second nonmagnetic layer acts as a mask for precise etching and milling, reducing leak magnetic flux and enhancing magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single nonmagnetic layer is used as a mask for etching the main magnetic pole layer, then the manufacturing process is simple, but the dimension precision and angle control of the inclined face are insufficient
Solution Approach 1:
The single nonmagnetic mask layer is segmented into two distinct layers: a first nonmagnetic layer and a second nonmagnetic layer. The second layer serves as the primary etching mask while the first layer acts as a sacrificial layer that is selectively removed to create the inclined face. This segmentation enables precise control of both the position and angle of the inclined face, directly resolving the dimension precision issue without excessive complexity.
Solution Approach 2:
The second nonmagnetic layer is formed first as a precise mask pattern, and then the first nonmagnetic layer is deposited over it. This preliminary action of establishing the mask pattern before adding the sacrificial layer ensures that the etching process will produce the desired inclined face geometry with high precision, addressing the dimension control problem.
2Reliability
If the thickness of the main magnetic pole layer is gradually decreased toward the recording medium facing surface to form an inclined face, then the intensity of recording magnetic field is improved, but the control of formation position and angle becomes difficult
Solution Approach 1:
The two-layer nonmagnetic structure acts as an intermediary system that mediates between the desired inclined face geometry and the etching process. The second nonmagnetic layer defines the precise position and angle through its mask pattern, while the first nonmagnetic layer provides the material to be selectively removed. This intermediary structure enables precise control of the inclined face formation position and angle, directly resolving the manufacturing precision issue while maintaining recording performance.
3Manufacturing precision
If higher recording density is pursued, then more severe demand for dimension precision is generated, but existing forming methods cannot sufficiently address the demand
Solution Approach 1:
The two-layer nonmagnetic structure enables self-service in the etching process. The second nonmagnetic layer automatically serves as the etching mask that defines the inclined face geometry, while the first nonmagnetic layer automatically serves as the sacrificial material that is selectively removed. This self-service mechanism eliminates the need for complex external control systems, making the high-precision formation process easier to manufacture despite the severe dimension precision demands.
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 method enables the formation of a main magnetic pole layer with high precision dimensions, reducing leak magnetic flux and improving recording performance by achieving a higher magnetic flux density.
Implementation Method 1
forming a first mask pattern on the second nonmagnetic layer and removing, through a first etching process, the second nonmagnetic layer in a region which is not covered with the first mask pattern
Implementation Method 2
selectively performing a first milling process on the first nonmagnetic layer and the magnetic layer with the pattern of the second nonmagnetic layer as a mask
Data Source
AI summary
In a perpendicular magnetic write head manufacturing method a magnetic layer is formed on a substrate. On the magnetic layer, first and second nonmagnetic layers are formed with different materials. A mask pattern is formed on the second nonmagnetic layer, and the second nonmagnetic layer in a region not covered with the mask pattern is removed. Thereby, the patterned second nonmagnetic layer is formed while leaving the first nonmagnetic layer. The mask pattern is removed and a milling process is selectively performed on the first nonmagnetic layer and the magnetic layer with the patterned second nonmagnetic layer as a mask to remove all of the first nonmagnetic layer in an exposed region and to dig down the magnetic layer in the exposed region, thereby forming a main magnetic pole layer having an inclined part whose thickness decreases with distance from an edge position of the patterned second nonmagnetic layer.