Graded Side Shield for PMR Writer Pole Tip
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing perpendicular magnetic recording (PMR) write heads with non-conformal side shields face issues of asymmetries and non-uniformities, affecting on-track and off-track performance due to difficulties in aligning separate masks, leading to side gap asymmetries and reduced recording density.
Innovation Solution
A graded shield configuration is introduced where the main pole is partially or completely surrounded by a shield that is conformal at the top portion and non-conformal at the bottom portion, using a bi-layer substrate of MO/Al2O3, allowing for selective etching and alignment to create uniform and non-uniform side gaps, improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If non-conformal side shields are used to increase recording density, then areal recording density is improved, but side gap asymmetries and non-uniformities occur due to mask alignment difficulties
Solution Approach 1:
The side shield is designed with different gap characteristics at different locations: conformal at the top portion and non-conformal at the bottom portion. This local differentiation allows the top conformal region to provide uniform side gaps for manufacturing precision, while the bottom non-conformal region enables higher areal recording density through optimized field confinement.
2Productivity
If conformal side shields are used to maintain uniform side gaps, then manufacturing precision is improved, but areal recording density is limited
Solution Approach 1:
The side shield transitions from fully conformal to partially conformal design, where only the top portion maintains conformality for manufacturing ease, while the bottom portion adopts non-conformal geometry to enhance field confinement and increase areal recording density beyond what fully conformal shields can achieve.
3Reliability
If graded shield configuration is used to combine conformal and non-conformal portions, then on-track and off-track performance are improved, but device complexity increases
Solution Approach 1:
The side shield is segmented into two distinct portions along the air bearing surface: a top conformal portion and a bottom non-conformal portion. This segmentation allows each portion to independently optimize its function while being integrated into a single manufacturable structure through sequential deposition processes.
Solution Approach 2:
The shield geometry is extended in the vertical dimension perpendicular to the air bearing surface, creating a three-dimensional graded structure. This adds complexity to the shield shape but can be manufactured using standard sequential deposition and etching techniques, making the complexity manageable.
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 graded shield configuration enhances both on-track and off-track performance by maintaining the benefits of conformal and non-conformal shields, increasing the maximum vertical field and overwrite performance while reducing side fringing, thus achieving higher areal recording densities.
Implementation Method 1
using a bi-layer substrate of MO/Al2O3, allowing for selective etching and alignment to create uniform and non-uniform side gaps
Implementation Method 2
By means of fringing magnetic fields that extend between two emerging pole pieces, longitudinal recording heads form small magnetic domains within the surface plane of the magnetic medium
Implementation Method 3
a soft magnetic underlayer (SUL) formed beneath the magnetic layer acts as a stabilizing influence on these perpendicular domain structures
Data Source
AI summary
A perpendicular magnetic recording (PMR) head is fabricated with a pole tip shielded laterally by a graded side shield that is conformal to the shape of the pole tip at an upper portion of the shield but not conformal to the pole tip at a lower portion. The shield includes a trailing shield, that is conformal to the trailing edge of the pole tip and may include a leading edge shield that magnetically connects two bottom ends of the graded side shield.