Patent Application
20090110962
1. Technical Field
The present invention relates in general to the construction of perpendicular media and, in particular, to an improved system, method, and apparatus for eliminating an adhesion layer between the glass substrate and the soft underlayer in perpendicular media in order to reduce the cost of fabricating perpendicular media for hard disk drives.
2. Description of the Related Art
Perpendicular recording is becoming the dominant recording technology for the hard disk drive (HDD) industry. With a severe price war taking place between competitors, reductions in the cost of media fabrication is a top priority for all HDD vendors. The perpendicular media tends to have more layers than longitudinal media, and it requires expensive sputtering tools that have more process chambers than conventional sputtering tools.
As shown in
One way to significantly reduce manufacturing cost is to remove the adhesion layer by using a conventional, low cost sputtering machine with fewer process chambers. Alternatively, one extra chamber may be used in the conventional sputtering machine to improve the media performance without increasing the process chamber numbers. Although these processes are workable, still other solutions for an improved system, method, and apparatus for reducing the cost of fabricating perpendicular media would be desirable.
Embodiments of a system, method, and apparatus for eliminating adhesion layers between substrates and soft underlayers (SUL) to reduce the cost of fabricating perpendicular media are disclosed. The thickness of the SUL is reduced from a conventional size of over 100 nm down to a thickness of less than 50 nm. By reducing the total SUL thickness, the film adhesion strength between the substrate and SUL is increased, and the adhesion layer can be eliminated for lower cost production of disk drives having perpendicular media.
In one embodiment, the perpendicular media comprises only a substrate, the SUL, an exchange break layer (EBL), a recording layer, and a protective overcoat. The substrate may be formed from a glass material or an aluminum alloy material. The SUL may comprise one layer or multiple layers formed from non-crystalline, amorphous materials or nanocrystalline materials. The SUL also may comprise multiple layers with non-magnetic or slightly magnetic layers, and the recording layer may be formed from a Co-based alloy with perpendicular anisotropy. The overcoat may comprise a carbon or silicon-based material.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings.
So that the manner in which the features and advantages of the present invention, which will become apparent, are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings which form a part of this specification. It is to be noted, however, that the drawings illustrate only some embodiments of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
Referring to
In one embodiment (
The SUL 23 may comprise one layer or multiple layers formed from non-crystalline, amorphous materials such as FeCoTaZr, FeCoTaZrB, FeCoTaZrBSi, FeCoTaZrMoB, CoB, CoFeSiB, CoFeB, CoZrTa, CoZrNb, CoZrTaNb, FeCoTaZr, FeCoB, FeCoB, FeCoBCr, FeCoTaB, FeCoTa, and/or FeCoTaCr. Alternatively, the SUL 23 may be formed from microcrystalline or nanocrystalline materials. Microcrystalline and nanocrystalline materials are intermediate structures between amorphous SUL and crystalline SUL. These materials have a short range of order of crystal that is less than 10 nm in size, but in the long range, there is no crystalline correlation between those ordered particles. Its mechanical behavior is very similar to amorphous film rather than crystalline film. In another embodiment, the SUL 23 may comprise anti-ferromagnetically coupled soft magnetic underlayers.
The EBL 25 also may comprise multiple layers with non-magnetic or slightly magnetic layers. The recording layer 27 may be formed from a Co-based alloy with perpendicular anisotropy. The overcoat 29 may comprise a carbon or silicon-based material.
Referring now to
As shown in
The method also may comprise sputtering the SUL without an atmosphere of krypton or xenon gas, and/or forming the SUL from one or more non-crystalline, amorphous materials. The method also may comprise forming the substrate from a material selected from the group consisting of glass and an aluminum alloy, and/or forming the SUL from one or more layers of material selected from the group consisting of non-magnetic and slightly magnetic materials (e.g., FeCoTaZr, FeCoTaZrB, FeCoTaZrBSi, FeCoTaZrMoB, CoB, CoFeSiB, CoFeB, CoZrTa, CoZrNb, CoZrTaNb, FeCoTaZr, FeCoB, FeCoB, FeCoBCr, FeCoTaB, FeCoTa, and/or FeCoTaCr).
In addition, the method may comprise forming the recording layer from a Co-based alloy with perpendicular anisotropy, and the overcoat from one of a carbon-based and silicon-based material. Furthermore, the method may comprise forming the recording layer without an additional layer of NiCrB or NiCrBCo between the recording layer and the SUL, and forming the recording layer without B4C.
The invention offers numerous advantages over the prior art. For example, the invention does not require a crystalline SUL for better orientation of the recording layer. The invention also does not require an additional layer of NiCrB or NiCrBCo between the SUL and the recording layer, and it does not require B4C in the recording layer. In addition, many prior art methods require the SUL to be sputtered with an atmosphere of krypton or xenon gas. Avoiding each of these prior art requirements during the fabrication of perpendicular media further reduces manufacturing costs.
While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.
