Patterned Leading Shield Notch for PMR Write Head
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Solution Overview
Problem
Current perpendicular magnetic recording (PMR) write heads face challenges in achieving higher bits per inch (BPI) and tracks per inch (TPI) capabilities while maintaining low bit error rate (BER) and minimizing adjacent track interference (ATI), with insufficient emphasis on leading shield design.
Innovation Solution
A patterned leading shield structure with a notch is introduced, where the leading shield has a tapered side extending from the air bearing surface (ABS) to a back end, intersecting with a main pole leading side, and featuring a recessed notch aligned below the main pole leading side, allowing additional magnetic flux release and return, enhancing overwrite capability and bit error rate while preserving adjacent track interference and side shield response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional leading shield design is used, then the structure is simple and manufacturing is easier, but overwrite capability and bit error rate performance are insufficient
Solution Approach 1:
The leading shield is divided into multiple segments: a first portion extending from the ABS and a second portion extending from the first portion. This segmentation allows each portion to be optimized independently for flux distribution, improving overwrite capability and bit error rate while maintaining manufacturability through modular design.
Solution Approach 2:
Different portions of the leading shield are given different geometries and orientations tailored to their specific functions. The first portion is optimized for one aspect of flux management while the second portion addresses another, allowing local optimization of magnetic flux distribution to enhance writing performance.
2Reliability
If the leading shield geometry is modified to improve flux distribution, then overwrite capability improves, but manufacturing precision requirements increase
Solution Approach 1:
By segmenting the leading shield into distinct portions with clear geometric definitions, each portion can be manufactured and assembled with standard tolerances. The modular structure reduces the cumulative precision requirements compared to a monolithic complex geometry, making the design more manufacturable while achieving the desired flux distribution.
3Productivity
If a patterned leading shield with notch is implemented, then magnetic flux distribution is improved and BPI increases, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patterned leading shield is implemented through segmentation into portions that can be formed using standard photolithography and etching processes. The notch and tapered sides are created as part of the segmented structure, allowing complex patterns to be manufactured using conventional semiconductor fabrication techniques rather than requiring advanced or specialized processes.
4Productivity
If the leading shield is optimized for higher BPI, then storage area density improves, but adjacent track interference may increase
Solution Approach 1:
The leading shield portions are designed with specific local geometries that create favorable magnetic flux distribution patterns. The tapered sides and notch configuration locally concentrate and direct flux in ways that improve writing performance for higher BPI while the overall shield geometry maintains appropriate field gradients to minimize adjacent track interference.
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 patterned leading shield design improves overwrite capability and bit error rate while maintaining tracks per inch and adjacent track interference, achieving higher BPI and BER performance without significant tradeoffs, thus enhancing storage area density.
Implementation Method 1
allowing additional magnetic flux release and return, enhancing overwrite capability and bit error rate
Data Source
AI summary
A method is disclosed for forming a perpendicular magnetic recording writer with an all wrap around (AWA) shield design wherein a surface of the leading shield that contacts the lead gap has a notch that is recessed 20 to 120 nm from the air bearing surface (ABS) and has a first side with a down-track dimension of 20-200 nm that is aligned parallel to the ABS. In one embodiment, the notch is aligned below the main pole leading side and has a cross-track width substantially the same as the track width of the main pole trailing side. The notch has two sidewalls formed equidistant from a center plane that bisects the leading shield wherein each sidewall intersects the first side at an angle of 90 to 170 degrees. Accordingly, overwrite and bit error rate are improved while adjacent track interference and tracks per square inch capability are substantially maintained.