Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2002-01-14
2004-04-27
Tugbang, A. Dexter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S428000, C029S603070, C029S603120, C029S603160, C029S851000, C216S022000, C216S039000, C216S041000, C264S434000, C360S234500, C360S235800, C438S003000
Reexamination Certificate
active
06725526
ABSTRACT:
FIELD OF THE INVENTION
Embodiments of the present invention relate generally to disk drive systems and to microsuspension structures which support read/write recording heads within the systems.
DESCRIPTION OF RELATED ART
Direct access storage devices typically include a rotatable magnetic disk having concentric data tracks defined for storing data, and a magnetic recording head or transducer for reading data from and writing data to the various data tracks. In typical disk drive systems, a stack of one or more magnetic disks is mounted over a spindle on a drive motor. The system also includes a head actuator including a head suspension assembly for supporting and moving the magnetic recording head relative to the disk surfaces, and electronic circuitry for processing signals to implement various functions of the disk drive. The head suspension assembly typically provides an arm-like structure. The suspension assembly supports the head close to the surface of the disk as the disk rotates. The magnetic head is carried on a slider having an air bearing surface which is positioned during operation adjacent to the data surface of the disk and usually separated from the surface of the disk by a cushion of air generated by the rotating disk. The terms “head” and “slider” are sometimes both used to refer to the slider having a head attached thereon. The slider design affects the efficiency, density, speed and accuracy with which the data can be read and written to the disk.
The suspension assembly connects the slider to a rotary or linear actuator which operates to move the suspension assembly to position the magnetic head directly adjacent to the desired track location on the disk. Suspension assemblies are typically shaped as an elongated load beam adapted to be connected to an actuator arm at one end. The other end includes a flexure member on which the slider is positioned. The flexure member is designed to permit an amount of spring-type movement of the slider, while also being rigid in a lateral direction to minimize undesirable side to side motion of the slider. Steel has been used as a suspension assembly material due to its mechanical properties and because it can be milled into fine structures. However, as magnetic heads and sliders become smaller and lighter, smaller suspension assemblies with a higher width to thickness ratio are needed. However, materials such as steel have a limited strength to mass ratio.
Silicon has been proposed as a magnetic head suspension assembly material. The use of silicon for the entire head suspension assembly has certain advantages such as the ability to form certain electrical components directly on the assembly, and the ability to utilize certain processing methods similar to those used for integrated circuit manufacture. U.S. Pat. No. 5,711,063 describes a process for forming a magnetic head assembly in which silicon is cut into a suspension assembly shape and then masked and etched to remove additional silicon and to form structures such as a plateau on the head suspension assembly. However, micromachining silicon to form such structures is time consuming and complex and such silicon structures may lack the necessary mechanical properties needed for the suspension assembly.
SUMMARY
Certain embodiments relate to suspension structures for a magnetic recording head and methods for producing such suspension structures. The suspension arm contains a membrane structure that primarily supports the head structure. Other properties include the option to electrically conduct or isolate conductive paths to and from the head via the suspension arm.
Embodiments include a head suspension assembly including a suspension arm having a trench formed therein. The head suspension assembly also includes a membrane positioned on the suspension arm and adapted to support a slider thereon, wherein at least a portion of the membrane is positioned adjacent to the trench. In one aspect of certain embodiments, the suspension arm is silicon and the membrane is a glassy carbon material.
Embodiments also include a method for forming a head suspension assembly. The method includes forming a spacer layer in a portion of a substrate. The method also includes forming a transfer film having a mold of a suspension membrane therein, and filling the mold of the suspension membrane with a layer of material. The transfer film including the mold of the suspension membrane filled with the layer of material is positioned over the substrate. The layer of material is baked to densify at least a portion of the layer of material. The spacer layer is removed from the substrate to form a cavity extending a distance into the substrate, and the baked layer of material is at least partially positioned over the cavity.
Embodiments also include a method for forming a head suspension assembly, including forming a spacer layer in or on a silicon substrate. A transfer film having an opening defining the shape of a slider support membrane is provided, and the opening is filled with a resin material. The transfer film with the resin material therein is positioned in contact with the silicon substrate so that at least a portion of the resin material is positioned adjacent to the spacer layer. The resin material is baked to form a glassy carbon material, and the spacer layer is removed to form a cavity in the silicon substrate surface adjacent to the glassy carbon material.
Embodiments also include a method for forming a head suspension assembly, including forming a sacrificial layer in or on a portion of a substrate. A transfer film is formed across the substrate. A patterned photoresist layer is formed on top of the transfer film. The method also includes transferring the image of patterned photoresist layer through the transfer film, and removing the patterned photoresist layer. In addition, the sacrificial layer is removed to form a cavity extending a distance into the substrate.
Embodiments also include a disk drive for reading and writing disks. The disk drive includes at least one disk and read/write head adapted to read from and write to the disk. The disk drive also includes a slider onto which the read/write head is provided. The disk drive also includes a suspension assembly adapted to support the slider, wherein the suspension assembly includes a membrane positioned on a support arm having a cavity therein, and the membrane is positioned to extend adjacent the cavity. The disk drive also includes a rotatable hub for mounting the disk.
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Schueller et al., “Fabrication of glassy carbon microstructures by soft lithography,”Sensors and Actuators, A72 (1999) 125-139.
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Hitachi Global Storage Technologies - Netherlands B.V.
Kim Paul
Konrad Raynes & Victor LLP
Raynes Alan S.
Tugbang A. Dexter
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