Magnetic Recording Pole Fabrication via Seed Layer Segmentation
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Solution Overview
Problem
Conventional seed milling processes for fabricating magnetic recording poles in energy assisted magnetic recording (EAMR) transducers face challenges with over-milling and core damage, particularly on SiO2 platforms due to faster mill rates and higher power requirements compared to Alumina platforms.
Innovation Solution
A method involving a thin seed layer of CoNiFe (10 nm) is used for the writer pole area and a thicker seed layer (40 nm) for the field area, allowing for controlled seed layer removal with reduced mill time and power, specifically using a wafer patterning technique to differentiate seed layer thickness between device and field areas, and employing a sequence of photoresist layers and etching processes to protect the core during milling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional seed milling process is used with high mill power and long mill time to fully remove the seed layer, then the seed layer is completely removed, but over-milling occurs at the bottom of the pole and core damage may occur
Solution Approach 1:
The patent applies preliminary action by forming a trench in the seed layer before plating the magnetic pole. This trench exposes a portion of the underlying layer, allowing the seed layer to be naturally removed during plating without requiring aggressive milling. The trench is formed using photolithography and etching processes, creating a controlled geometry that guides the plating process and prevents over-milling at the pole bottom.
Solution Approach 2:
The patent segments the seed layer removal process into two distinct regions: a trench area where the seed layer is removed to expose the underlying layer, and a pole area where the seed layer remains as a plating substrate. This segmentation is achieved through photolithographic patterning that defines the trench geometry, allowing differential treatment of different regions during the plating process.
2Manufacturing precision
If the substrate is patterned to have different seed thickness over field area and device area, then fabrication control is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating a substrate with non-uniform seed layer thickness, where the device area has a thinner seed layer (10 nm) compared to the field area (40 nm). This local differentiation is achieved through photolithographic patterning and selective etching, allowing the device region to be milled with lower power and shorter time while the field area maintains sufficient seed thickness for subsequent processing steps.
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 reduces the risk of over-milling and core damage, enabling precise fabrication of magnetic recording poles on SiO2-based EAMR devices with less mill time and power, maintaining the integrity of the core and improving fabrication control.
Implementation Method 1
Light is guided by the waveguide 110 to the NFT 104 near the air-bearing surface (ABS). The NFT 104, in turn, focuses the light to a magnetic recording medium, such as a disk. During operation, light from the laser is received by the EAMR transducer 102 through the grating 106, where the waveguide 110 directs light from the grating 106 to the NFT 104. The NFT 104 focuses the light from the waveguide 110 and heats a small region of the magnetic recording medium.
Data Source
AI summary
Systems and methods for fabricating a microelectric device are provided herein. Particular embodiments provide systems and methods for fabricating a magnetic recording pole for a magnetic recording head, such as an energy assisted magnetic recording (EAMR) head commonly used in a disk storage device. Some embodiments provide for systems and methods of fabricating magnetic recording poles that protect the core of the magnetic recording head during the removal of removal of seed layers.