Ta/C Hard Mask for Ion Implantation in Magnetic Media
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Solution Overview
Problem
Conventional hard masks for ion implantation in patterning magnetic recording media fail to meet multiple requirements, such as stopping ions, achieving high aspect ratios for small feature sizes, withstanding etching, and being removable without damaging the magnetic layer, due to issues like resist etching and damage from fluorine-based dry etch chemistries.
Innovation Solution
A hard mask configuration using a combination of tantalum (Ta) and carbon (C) layers, where a thin Ta layer is used for pattern transfer and a thick C layer for protection, allowing for high aspect ratio and effective ion stopping, and subsequent removal using specific etch chemistries to prevent damage to the magnetic layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single metal hard mask comprising Ta is used, then ion stopping capability is achieved, but aspect ratio extendibility to small features is not possible
Solution Approach 1:
The patent employs a composite hard mask structure consisting of multiple layers including Ta and other materials. This composite configuration enables the mask to achieve both high aspect ratio for small feature sizes and effective ion stopping capability, as each layer contributes different properties that collectively satisfy both requirements.
Solution Approach 2:
The hard mask is divided into multiple discrete layers rather than using a single material. This segmentation allows each layer to be optimized for specific functions - some layers provide ion stopping while others maintain the necessary aspect ratio for small features, resolving the contradiction between these two requirements.
2Reliability
If a single metal hard mask comprising Ta is used, then ion stopping capability is achieved, but removability without damaging magnetic layer is not possible
Solution Approach 1:
The composite mask structure includes layers selected for their differential etchability. The Ta layer provides ion stopping capability while other layers in the composite structure can be selectively removed using specific etch chemistries that do not damage the underlying magnetic layer, enabling easy removal without compromising the magnetic media.
Solution Approach 2:
The composite mask structure acts as an intermediary between the ion implantation process and the magnetic layer. The specific layer composition allows the mask to perform its protective function during ion implantation while enabling selective removal through intermediary etch processes that spare the magnetic layer.
3Ease of operation
If resist material is used for patterning, then pattern transfer is achieved, but resist etches away during ion implantation resulting in less sharp transitions
Solution Approach 1:
The hard mask serves as an intermediary layer between the patterned resist and the magnetic layer. The resist performs pattern transfer to the mask, while the hard mask maintains sharp transitions during ion implantation by resisting etching, thus preserving the sharp boundaries in the magnetic layer.
Solution Approach 2:
The resist material is used as a temporary, disposable patterning layer that is removed after transferring the pattern to the hard mask. The hard mask, being more durable, maintains the pattern integrity during ion implantation and is subsequently removed, while the resist's temporary nature allows it to be discarded after serving its pattern transfer function.
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
The Ta/C hard mask effectively stops ions, maintains high aspect ratio for small feature sizes, withstands etching, and is removable without damaging the magnetic layer, resulting in sharper transitions and higher areal density in patterned magnetic recording media.
Implementation Method 1
capable of stopping the ions from reaching the magnetic layer of the media
Implementation Method 2
robust enough to withstand the etching effects of the ion implantation process
Implementation Method 3
removable such that after the ion implantation process it can easily removed without damaging the magnetic layer
Data Source
AI summary
Embodiments of the present invention relate to systems and methods for designing and manufacturing hard masks used in the creation of patterned magnetic media and, more particularly, patterned magnetic recording media used in hard disk drives (e.g., bit patterned media (BPM)). In some embodiments, the hard mask incorporates at least one layer of Ta (tantalum) and at least one layer of C (carbon) and is used during ion implantation of a pattern onto magnetic media. The hard mask can be fabricated with a high aspect ratio to achieve small feature sizes while maintaining its effectiveness as a mask, is robust enough to withstand the ion implantation process, and can be removed after the ion implantation process with minimal damage to the magnetic media.