Magnetic Recording Transducer Side Shield Fabrication
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Solution Overview
Problem
Conventional methods for fabricating magnetic recording transducers often result in unwanted magnetic material at uncontrolled locations, such as inclusions and undercuts, which compromise the performance of the transducer.
Innovation Solution
A method involving a hard mask with a removal aperture and a side shield deposition mask is used to precisely form side shields, reducing extraneous magnetic material by controlling the shape and location of the apertures, thereby minimizing unwanted magnetic inclusions and undercuts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional wet etch mask method is used to form side shields, then the fabrication process is simple, but unwanted magnetic material appears at uncontrolled locations such as inclusions and undercuts
Solution Approach 1:
The patent divides the masking process into two separate masks: a first mask that defines the front edge of the side shield and a second mask that defines the back edge. This segmentation allows independent control of different geometric features, preventing unwanted magnetic material formation while maintaining fabrication simplicity.
Solution Approach 2:
The patent performs preliminary actions by forming the first mask and etching the front edge of the side shield before forming the second mask and etching the back edge. This sequential preliminary action ensures that magnetic material is deposited and removed in controlled stages, preventing uncontrolled inclusions and undercuts.
2Productivity
If a single mask is used for side shield formation, then the fabrication process is fast, but extraneous magnetic material remains at the air-bearing surface
Solution Approach 1:
The patent segments the side shield formation into two distinct etching operations with separate masks, allowing each mask to be optimized for its specific function. This ensures complete removal of extraneous magnetic material while maintaining a streamlined two-step process that preserves productivity.
Solution Approach 2:
The patent extracts and removes extraneous magnetic material by using the second mask to specifically target and remove material at the back edge of the side shield, including any inclusions or undercuts that formed during deposition, thereby improving transducer reliability.
3Manufacturing precision
If the mask aperture extends far from the pole in the track width direction, then complete side shield coverage is achieved, but unwanted magnetic material is deposited on remaining seed layer portions
Solution Approach 1:
The patent segments the masking function so that the first mask covers only the region needed for front edge definition, while the second mask covers the region needed for back edge definition. This prevents the mask from extending unnecessarily far from the pole, avoiding deposition of unwanted magnetic material on distant seed layer portions.
Solution Approach 2:
The patent applies local quality by making each mask aperture specifically sized and positioned for its local function. The first mask aperture is positioned to define the front edge, and the second mask aperture is positioned to define the back edge, ensuring coverage is provided only where needed rather than uniformly across all seed layer portions.
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 approach enhances the fabrication of side shields, reducing unwanted magnetic material at the air-bearing surface, improving the transducer's performance by better controlling the geometry and removing extraneous seed layer portions.
Implementation Method 1
A removal mask having a removal aperture therein is provided. The removal aperture exposes a portion of the pole proximate to the ABS location and a first portion of the aperture. The removal mask covers a second portion of the aperture in a track width direction from the ABS location of the pole and covers the second portion of the hard mask.
Implementation Method 2
A first portion of the nonmagnetic layer exposed by the removal aperture is removed, forming a side shield trench in the nonmagnetic layer.
Implementation Method 3
A seed layer for the side shield is deposited.
Implementation Method 4
A side shield deposition mask having a deposition aperture therein is provided. The deposition aperture exposes a first portion of the side shield trench and a portion of the nonmagnetic layer in the track width direction from the ABS location of the pole. The side shield deposition mask covers a second portion of the side shield trench.
Implementation Method 5
The transducer is planarized to remove a portion of the side shield material external to the side shield trench. A remaining portion of the side shield material forms the side shield.
Data Source
AI summary
A magnetic transducer having an air-bearing surface is described. The magnetic transducer includes a nonmagnetic layer on an underlayer, a pole having a plurality of sidewalls, a gap layer on the sidewalls, a seed layer and at least one side shield. The nonmagnetic layer has an aperture therein. The aperture is free of magnetic inclusions at the ABS. The pole is on the underlayer and within the aperture. The seed layer is for the side shield(s) and resides on the gap layer, a portion of the underlayer and a portion of the nonmagnetic layer. The side shield(s) residing on the seed layer and in the aperture. The side shield(s) are free of undercuts at the ABS.