Carbon Hard Mask for Sub-100 nm Write Pole Fabrication
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Solution Overview
Problem
Existing hard masks used in fabricating sub-100 nm write poles for magnetic transducing heads are unstable due to thickness issues and suffer from negative contamination, such as oxygen ion contamination, which affects the accuracy and steepness of the write pole's sidewalls.
Innovation Solution
A magnetic writer is developed with a non-magnetic, oxygen-free buffer material between the write pole and the substrate, using a carbon hard mask to pattern the write pole material, allowing for the formation of write poles with steeper sidewalls and improved stability by minimizing oxygen contamination during the milling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional hard mask materials (Al2O3, SiO2, SiON, poly-Si) are used to fabricate sub-100 nm write poles, then the hard mask can be deposited, but the patterned hard mask must be thicker than 100 nm which results in decreased stability and oxygen ion contamination
Solution Approach 1:
The patent changes the material parameter of the hard mask from traditional materials (Al2O3, SiO2, SiON, poly-Si) to carbon-based material. This material substitution enables the hard mask to be thinner (below 100 nm) while maintaining sufficient stability during the milling process, and eliminates oxygen ion contamination that plagues traditional hard mask materials.
2Length of moving object
If the hard mask thickness is reduced to enable sub-100 nm write pole fabrication, then the write pole width can be decreased to increase recording capacity, but the hard mask stability decreases
Solution Approach 1:
The patent changes the material parameter of the hard mask to carbon-based material, which has superior mechanical properties and stability. This enables the hard mask to maintain sufficient thickness (below 100 nm) for sub-100 nm write pole fabrication while retaining adequate stability during processing, unlike traditional hard mask materials that become unstable when made thin.
3Ease of manufacture
If traditional hard mask materials are used, then the fabrication process can proceed, but oxygen ion contamination occurs which affects sidewall steepness and accuracy
Solution Approach 1:
The patent uses carbon-based material as the hard mask, which creates an oxygen-free or inert environment during the milling process. This inert environment prevents oxygen ion contamination of the write pole sidewalls, enabling steep and accurate sidewalls while maintaining ease of fabrication.
Solution Approach 2:
The patent converts the potential harm of using carbon-based material (which can be reactive) into a benefit by utilizing its ability to prevent oxygen ion contamination. The carbon hard mask acts as a barrier that protects the write pole material from oxygen contamination during milling, turning a material choice that could be problematic into a solution that eliminates the harmful oxygen ion contamination effect.
Data Source
AI summary
A magnetic writer comprises a write pole, a substrate and a non-magnetic, oxygen-free buffer material. The write pole has a leading edge, a trailing edge, a first side and second side. The substrate is at the leading edge of the write pole. The non-magnetic, oxygen-free buffer material is located between the write pole and the substrate, and the oxygen-free buffer material is selected from Re, Ru, Os, Rh, Ir, and combinations thereof.