Patterned Hot Seed Design for Hard Disk Write Head ATI Reduction
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Solution Overview
Problem
The increasing demand for higher data storage capacity in hard disk drives is hindered by adjacent track interference (ATI) caused by the wide hot seed (HS) in write heads, which reduces track per inch (TPI) while attempting to maintain bit per inch (BPI) and down-track gradient.
Innovation Solution
A patterned hot seed design is implemented, featuring a multi-step patterning process that partially or completely removes portions of the HS at multiple sides, creating designs such as a two-step cliff or flared angle, reducing magnetic volume and interference while maintaining magnetic flux concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hot seed (HS) is made wide to maintain magnetic flux concentration and down-track gradient, then write performance is improved, but adjacent track interference (ATI) increases and track per inch (TPI) decreases
Solution Approach 1:
The hot seed is divided into multiple segments along its length, with different widths at different positions. The HS has a narrower width near the write gap and a wider width toward the trailing shield, creating distinct functional zones that separate magnetic flux concentration from return field management
Solution Approach 2:
Different portions of the hot seed are given different widths to optimize local functions. The narrow portion near the write gap concentrates magnetic flux for effective writing, while the wider portion toward the trailing shield manages the return field to reduce adjacent track interference
2Measurement precision
If the hot seed (HS) is made wide to maintain bit per inch (BPI) and down-track gradient, then magnetic flux concentration is improved, but track per inch (TPI) decreases
Solution Approach 1:
The hot seed width is segmented along its length, creating a gradient structure that narrows toward the write gap and widens toward the trailing shield, allowing simultaneous optimization of BPI and TPI
Solution Approach 2:
The solution moves from a single-width-dimensional approach to a two-dimensional width variation along the HS length, allowing independent optimization of magnetic flux concentration (affecting BPI) and return field distribution (affecting TPI)
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 HS design effectively reduces adjacent track interference, maintaining BPI and improving TPI by concentrating the return field in the center, thus enhancing write head performance and data storage capacity.
Implementation Method 1
a main pole (MP) configured to concentrate a magnetic flux
Implementation Method 2
The patterned HS design effectively reduces adjacent track interference, maintaining BPI and improving TPI by concentrating the return field in the center
Data Source
AI summary
The present embodiments relate to a write head design with a patterned hot seed (HS). Particularly, the HS can be patterned as part of a multi-step patterning process that can partially or completely remove portions of the HS at multiple sides to form various designs. For example, the HS can have a two-step cliff design, etching multiple steps around an un-patterned center portion, and a flared angle. The designs of the patterned HS can improve write head performance.