Amorphous Carbon Mask Patterning via Oxide Replacement
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Solution Overview
Problem
Contamination of the amorphous carbon layer during milling by metallic residue from a metal mask affects the control dimensions and fidelity of patterning in the pattern fabrication process, making it difficult to clean without damaging the magnetic properties.
Innovation Solution
Replacing the metal mask with an oxide layer and using chemical etching processes, such as reactive ion beam etching with gases like CHF3 and O2, to remove residual layers and prevent contamination, ensuring high fidelity image transfer and clean surfaces for patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metal mask is used to transfer the pattern image, then the pattern can be transferred to the magnetic layer, but metallic residue contaminates the amorphous carbon mask layer, degrading patterning precision and magnetic layer properties
Solution Approach 1:
The patent extracts and removes the metal mask from the patterning process entirely, replacing it with a metal-free amorphous carbon mask layer. This eliminates the source of metallic residue contamination while maintaining the essential pattern transfer function through sequential etching processes.
Solution Approach 2:
The patent introduces an amorphous carbon mask layer as an intermediary material between the pattern source and the magnetic layer. This intermediary serves the pattern transfer function without introducing harmful metallic contamination, and can be cleanly removed after patterning.
2Object-affected harmful factors
If metallic residue is cleaned from the amorphous carbon layer, then contamination is reduced, but the magnetic properties of the magnetic layer are affected
Solution Approach 1:
The patent employs a disposable amorphous carbon mask layer that is intentionally designed to be temporary and easily removable. This mask performs its pattern transfer function and is then cleanly removed using oxygen plasma or chemical methods, leaving no harmful residue and preserving magnetic layer integrity.
Solution Approach 2:
The patent replaces mechanical or chemical cleaning methods that could damage the magnetic layer with a controlled oxygen plasma removal process. This substitution allows for clean mask removal without affecting the magnetic properties of the underlying layer.
3Object-affected harmful factors
If the amorphous carbon mask layer is used instead of metal mask, then metallic residue contamination is prevented, but additional process steps are required for mask removal
Solution Approach 1:
The patent exploits the chemical parameter differences between amorphous carbon and the magnetic layer. By using oxygen plasma, which selectively reacts with and removes carbon-based materials, the mask is eliminated without affecting the magnetic layer, simplifying the overall process despite the additional removal step.
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 method effectively prevents contamination, maintains high fidelity and control dimensions, and ensures the magnetic properties are not affected, resulting in a simple, cost-effective, and fast patterning process with high-quality throughput.
Implementation Method 1
chemical etching processes, such as reactive ion beam etching with gases like CHF3 and O2
Implementation Method 2
chemical etching processes, such as reactive ion beam etching with gases like CHF3 and O2, to remove residual layers
Implementation Method 3
oxidation to remove organic residue
Data Source
AI summary
The embodiments disclose a method of fabricating a stack, including replacing a metal layer of a stack imprint structure with an oxide layer, patterning the oxide layer stack using chemical etch processes to transfer the pattern image and cleaning etch residue from the stack imprint structure to substantially prevent contamination of the metal layers.