Etching a substrate: processes – Forming or treating article containing magnetically...
Reexamination Certificate
1999-11-01
2001-12-04
Gulakowski, Randy (Department: 1746)
Etching a substrate: processes
Forming or treating article containing magnetically...
C029S603010, C029S603140, C029S603150, C360S112000, C360S125330
Reexamination Certificate
active
06325947
ABSTRACT:
TECHNICAL FIELD
This invention relates to merged thin film magnetic heads, and, more particularly, to merged thin film magnetic heads having multi-layer thin film coil structures in the yoke regions thereof, air bearing sliders and magnetic storage systems employing merged thin film magnetic heads, and the methods for fabricating merged thin film magnetic heads and multi-layer thin film coil structures and air bearing sliders employing merged thin film magnetic heads and multi-layer thin film coil structures.
BACKGROUND OF THE INVENTION
Merged thin film magnetic heads are used to perform both “write” and “read” operations on magnetic media. The write and read operations are performed by separate write and read thin film heads which are merged together in a single thin film structure. Typically, the write head is an inductive structure with a thin film core of ferromagnetic material having a gap with a multi-turn coil wrapped around the thin film core which generates magnetic fields across the gap in response to electrical signals in the coil. The read head is typically a magnetoresistive read sensor which detects magnetic field signals through the resistance changes of the element as a function of the strength of the magnetic flux being sensed by the read sensor.
The merged thin film magnetic head is typically employed to write (or record) data as magnetic signals on a recording surface of a recording media and to read the recorded data as magnetic signals. Examples of recording media include magnetic disks which rotate at high speed, or magnetic tape which is moved in a linear fashion. The merged thin film magnetic head is typically closely spaced from the recording surface, often on an air bearing slider which has an air bearing surface which rides on an air bearing at the surface of a rotating disk, but also as a contact or near contact transducer.
The writing of data is accomplished by a signal in the thin film coil which induces a magnetic flux in the core. The core has two opposed pole pieces which terminate in two pole tips separated by a thin gap. The magnetic flux induced by the coil creates a magnetic field which extends beyond the core at the gap and to the recording media, magnetizing the media. The reading of data is accomplished by a read sensor positioned adjacent to the gap and pole pieces and between two shields which “shield” the read sensor from the write flux.
So as to increase the density of data recorded on the recording media, it is desirable to reduce the physical size of the merged thin film magnetic head. But, reducing the size of the head reduces the room available for windings of the thin film coil. The top pole piece of the thin film merged head is formed on top of the thin film coil and is kept as flat as possible and as short as possible between the back gap and pole tip. The typical merged thin film magnetic head has only one layer for the thin film coil and, since the induced magnetic flux is directly related to the number of turns of the coil, has more than one turn of the coil spaced apart in the single layer in the yoke region between the pole tips and the back gap.
As the head is reduced in size, the distance between the pole tips and back gap must also be reduced. To attempt to maintain a plurality of turns for the thin film coil, it would be advantageous to stack the turns in layers. However, each added coil layer raises the coil by the thickness of the layer and of the associated insulation to a substantially greater height than the pole tips and back gap, so that the top pole piece becomes highly sloped (apex angle) towards the pole tip and is also sloped toward the back gap, resulting in a high profile head. As described in coassigned U.S. Pat. No. 5,621,596, Santini, the high apex angle and high sloping layers pose a problem in construction of the head. To reduce the slope angles, the region in the yoke for placement of the thin film coil must be placed a distance away from the pole tip and away from the back gap, lengthening the pole pieces and reducing their efficiency.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a merged thin film magnetic head with a multi-turn coil in multiple layers while maintaining a low profile.
Disclosed is a merged thin film magnetic head having a first shield layer and a combined second shield and bottom pole piece layer arranged in a sandwich supporting a read sensor therebetween at the pole tip region. The combined second shield and bottom pole piece layer are magnetically coupled with the first shield layer at the pole tip end of the yoke region adjacent the read sensor, and overlaying and magnetically coupled with the first shield layer at the back gap region. A patterned opening is provided in the combined second shield and bottom pole piece layer at the yoke region thereof exposing the first shield layer and forming a flat planarization surface thereon. A plurality of stacked thin film coil layers are provided in the patterned opening, and a top pole piece layer overlies the thin film coil at the yoke region, overlies the bottom pole piece at the pole tip region providing a pole tip and gap thereat, and overlies the bottom pole piece at the back gap region.
The patterned opening which exposes the first shield layer allows the provision of a multi-layer coil while maintaining a low profile of the head.
A magnetic air bearing slider assembly is disclosed with a merged thin film head having a first shield layer and a combined second shield and bottom pole piece layer with a patterned opening in the combined second shield and bottom pole piece layer at the yoke region thereof exposing the first shield layer, a plurality of stacked thin film coil layers in the patterned opening, and a top pole piece layer overlaying the thin film coil at the yoke region, overlaying the bottom pole piece at the pole tip region providing a pole tip and gap thereat, and overlaying the bottom pole piece at the back gap region.
A magnetic data storage system is disclosed in another aspect of the present invention, comprising a magnetic storage medium having at least one track for the recording of data, and a magnetic transducer maintained close to the magnetic storage medium during relative motion therebetween. The transducer includes a patterned opening in the combined second shield and bottom pole piece layer at the yoke region which exposes the first shield layer, so that a plurality of stacked thin film coil layers are provided in the patterned opening, and the top pole piece layer overlies the thin film coil at the yoke region, the bottom pole piece at the pole tip region providing a pole tip and gap thereat, and overlies the bottom pole piece at the back gap region.
Still another aspect of the present invention comprises a method for forming a merged thin film magnetic head, comprising the steps of:
forming a first shield layer having a flat planarization surface;
disposing a read sensor including gap layers on the first shield layer at the pole tip region;
forming a patterned combined second shield and bottom pole piece layer overlaying the read sensor arranged in a sandwich having the read sensor between the first shield layer and the bottom pole tip, the combined second shield layer and bottom pole piece overlaying and magnetically coupled with the first shield layer at the pole tip end of the yoke region, and overlaying and magnetically coupled with the first shield layer at the back gap region, wherein the pattern of the combined second shield and bottom pole piece layer forms an opening in the yoke region thereof exposing the flat planarization surface of the first shield layer;
depositing a plurality of thin film coil layers at the flat planarization surface of the first shield layer; and
depositing a top pole piece layer overlaying the thin film coil.
Additionally, a method is disclosed for fabricating an air bearing slider and merged thin film magnetic head comprising the steps of providing a slider substrate having a sensor surface, forming a first shield layer having a flat pl
Garfunkel Glen Adam
Lee Edward Hinpong
Smyth Joseph Francis
Yuan Samuel Wonder
Ahmed Shamim
Gulakowski Randy
Holcombe John H.
International Business Machines - Corporation
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