Magnetic head with thin gap layers

Details Magnetic head with thin gap layers Magnetic head with thin gap layers

2001-01-29

2004-03-16

Letscher, George J. (Department: 2653)

Dynamic magnetic information storage or retrieval

Head

Magnetoresistive reproducing head

Reexamination Certificate

active

06707647

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the fabrication of magnetic heads for hard disk drives, and particularly to the fabrication of insulation layers within the read head portions of such magnetic heads.
2. Description of the Prior Art
To increase the areal data storage density of hard disks for hard disk drives, the data bits within the tracks upon such hard disks are written closer together, so that a greater number of bits per inch are recorded. To efficiently read data from a data track with such a greater number of bits, the read head portion of a magnetic head of a hard disk drive must be structured such that the resolution of the read heads is increased.
The read heads of the prior art magnetic heads are fabricated utilizing thin film deposition techniques on an upper surface of a wafer substrate. In fabricating the read head portion, a first electrical insulation layer is deposited upon the surface of the substrate, followed by the deposition of a magnetic shield, followed by a first gap insulation layer, followed by the fabrication of a plurality of layers and structures that generally include a plurality of active read head magnetic layers, magnetic hard bias elements and electrical lead traces. Thereafter, a second gap insulation layer is deposited, followed by a second magnetic shield, another insulation layer, and further magnetic head components such as write head structures, that complete the magnetic head.
One of the problems associated with prior art read heads so designed is that they have thick gap insulation layers. Consequently, the prior art read heads display low resolution because resolution is adversely affected by the spacing between the two magnetic shields i.e. thicker the gap insulation layers, greater the spacing between the two magnetic shields and lower the resolution. Even read heads designed with thinner gap insulation layers are not free of problems. One of the problems associated with prior art read heads with thinner gap insulation layers is the increased potential for electrical shorts between the electrical leads (and the sensor) and the magnetic shields due to the thinness of the gap insulation layers. Another problem associated with prior art read heads with thinner gap insulation layers is the lack of efficient electrical insulation. In these read heads, the gap insulation layers are so thin that they are unable to perform the function of electrical insulation effectively.
The present invention seeks to solve these problems associated with prior art read heads by providing new gap materials and deposition methods to produce thinner gap insulation layers that ensure high resolution of the read heads and that also provide robust electrical insulation.
SUMMARY OF THE INVENTION
The hard disk drive of the present invention includes a magnetic head wherein the read head portions of the magnetic head have novel gap insulation layers between the sensor and the two magnetic shields. In a preferred embodiment, the second of the gap insulation layers is made up of two portions. The first gap insulation portion is disposed over electrical leads in the read head and is thick enough to help ensure electrical insulation between the electrical leads and the second magnetic shield. The second portion of the gap insulation layer is disposed over the first gap insulation portion and also directly over the top portion of the sensor. It can be thinner than the first gap insulation portion. The second gap insulation portion ensures minimal spacing between the two magnetic shields. The gap insulation layers are made up of multilayer laminations wherein each lamination in the multilayered structure is made of an oxide of a metal selected from the group consisting of aluminum, silicon, chromium and tantalum. In accordance with the present invention, the fabrication of an individual lamination layer is a two step process starting with the deposition of a thin film of metal on a substrate layer, and then the oxidation of the deposited metal film to form a first metal oxide lamination. Each lamination may have a thickness of 10 Å to 50 Å. The process is repeated until a multilayered lamination structure of a desired thickness is formed. A preferred embodiment of the present invention includes 5-10 laminations in the multilayer structure, such that the total thickness of a gap insulation layer is approximately 50 Å-500 Å. The laminations are each fabricated by a process such as sputter deposition.
It is an advantage of the magnetic head of the present invention that it includes thin G
1
and G
2
gap insulation layers such that the distance between the magnetic shields of the read head is reduced.
It is another advantage of the magnetic head of the present invention that it includes a G
2
insulation layer having a first gap insulation layer portion and a second gap insulation portion, wherein the first gap insulation portion is disposed over the read head electrical leads and the second portion is disposed over the sensor and the first gap insulation layer portion.
It is a further advantage of the magnetic head of the present invention that it includes a read head with a G
2
insulation layer having a thinner second gap insulation portion formed of a laminated multilayer structure that reduces the distance between the sensor and the second magnetic shield.
These and other features and advantages of the present invention will no doubt become apparent to those skilled in the art after having read the following detailed description, which makes reference to the several figures of the drawings.


REFERENCES:
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patent: 5764567 (1998-06-01), Parkin
patent: 5801984 (1998-09-01), Parkin
patent: 5862022 (1999-01-01), Noguchi et al.
patent: 5898547 (1999-04-01), Fontana, Jr. et al.
patent: 5962080 (1999-10-01), Tan et al.
patent: 5966012 (1999-10-01), Parkin
patent: 6452761 (2002-09-01), Carey et al.
patent: 09198619 (1997-07-01), None
patent: 11181564 (1999-07-01), None

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