Granular Masking Layer for Sub-10nm Magnetic Media Patterning
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Solution Overview
Problem
Current techniques for fabricating magnetic recording media struggle to achieve high data storage density and small grain sizes without degrading magnetic properties, particularly with traditional sputtering processes, and face challenges in patterning features smaller than 20 nanometers due to mask erosion during reactive ion etching with argon carrier gases.
Innovation Solution
A method involving the deposition of a non-granular magnetic layer on a substrate, followed by a granular masking layer with two materials forming grains and grain boundaries, where the grain boundary material is removed to create a hard mask, and unmasked portions of the magnetic layer are etched using reactive ion etching with carrier gases like helium or neon, which reduces mask erosion and allows for pattern transfer of features less than 10 nanometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional sputtering processes are used to reduce grain size for high data storage density, then data storage density is improved, but magnetic properties are degraded
Solution Approach 1:
The invention separates the grain size control function from the magnetic layer itself by introducing a distinct granular masking layer. The magnetic layer remains non-granular and continuous, preserving its magnetic properties, while the masking layer is segmented into grains that define the pattern. This segmentation allows high-density patterning without degrading the magnetic layer's properties.
Solution Approach 2:
The granular masking layer acts as an intermediary between the deposition process and the magnetic layer. It transfers the grain pattern to the magnetic layer through selective removal and RIE etching, enabling precise grain size control while the magnetic layer itself maintains its optimal continuous structure for magnetic performance.
2Productivity
If reactive ion etching with argon carrier gas is used for pattern transfer, then etching capability is improved, but mask erosion increases preventing sub-20 nanometer patterning
Solution Approach 1:
The invention changes the carrier gas parameter from argon to helium or neon. This parameter change reduces the ion mass and energy transfer to the mask, minimizing mask erosion while maintaining sufficient etching capability to transfer sub-10 nanometer patterns from the granular mask to the magnetic layer.
Solution Approach 2:
The process creates a precise copy of the granular mask pattern onto the magnetic layer. By using helium or neon RIE, the mask pattern is transferred with high fidelity at sub-10 nanometer scale without significant mask material loss, achieving the desired pattern precision.
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 enables the fabrication of high-density magnetic recording media with precise grain sizing and maintains desirable magnetic properties, allowing for sub-10 nanometer feature patterning and reducing mask erosion, suitable for advanced magnetic technologies like MRAM and STT applications.
Implementation Method 1
A granular masking layer may then be deposited on the magnetic layer
Implementation Method 2
the grain boundary material may be removed (e.g., via an etching process)
Implementation Method 3
the unmasked portions of the magnetic layer may then be removed using a reactive ion etching (RIE) process
Data Source
AI summary
In some examples, a method including depositing a functional layer over a substrate; depositing a granular layer over the functional layer, the granular layer including a first material defining a plurality of grains separated by a second material defining grain boundaries of the plurality of grains; removing the second material from the granular layer such that the plurality of grains of the granular layer define a hard mask layer on the functional layer; and removing, via reactive ion etching with a carrier gas, portions of the functional layer not masked by the hard mask layer, wherein the carrier gas comprises a gas with an atomic number less than an atomic number of argon.