Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
1997-06-19
2001-02-06
Pianalto, Bernard (Department: 1762)
Stock material or miscellaneous articles
Composite
Of inorganic material
C427S130000, C427S131000, C427S132000, C427S337000, C427S367000, C428S900000
Reexamination Certificate
active
06183891
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method of manufacturing a layered magnetic head having a head face and comprising an inductive transducing system, in which method a non-magnetic, insulating material is deposited for forming a first insulation layer on which an inductive transducing element is formed, whereafter a non-magnetic, insulating material for forming a second insulation layer is deposited on the first insulation layer and the inductive transducing element formed thereon, whereafter a magnetic flux guide bounding a nonmagnetic gap layer is formed, whereafter the head face is formed, whereby the flux guide and the gap layer terminate in the head face.
The invention also relates to a thin-film magnetic head having a head face and comprising an inductive transducing system.
A method and a magnetic head of this type are known from EP-A 0 617 409. For forming an inductive transducing system, the known method starts from a polished base of ferrite having a plane basic surface. A first insulation layer of quartz is provided on the basic surface by means of, for example PE CVD, which quartz insulation layer is subsequently provided with an electrically conducting layer. This layer is structured to form turns of an inductive element. Subsequently, quartz is deposited for forming a second insulation layer, and a through-connection aperture is etched in said two insulation layers in an area removed from a head face to be formed at a later stage. Subsequently, a relatively thick third quartz insulation layer is provided. The assembly of layers jointly constitutes a thick insulation layer of a non-magnetic material. A structured layer of a mask material is formed on this layer. With the structured layer as a mask, the thick insulation layer is subsequently sputter-etched for forming a recess which extends as far as the base via the through-connection aperture. After sputtering, the remaining parts of the structured layer are removed by wet-chemical etching. A soft-magnetic layer is provided on the structured thick insulation layer obtained, while the recess is filled. The soft-magnetic layer is used for forming a flux guide. The soft-magnetic layer and the adjoining thick insulation layer are polished for creating a plane surface. An insulation layer is provided on this surface, whereafter a magnetoresistive transducing system is formed.
A drawback of the known method is that the flux guide is formed on a non-planarized surface, so that parts of the flux guide will extend between turns of the inductive element, which has a detrimental influence on the efficiency of the inductive transducing system. Moreover, the known method does not allow any freedom of choice of the distance between the basic surface and the soft-magnetic layer, because the distance is entirely determined by the thickness of the insulation layers provided to form the gap length.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the invention to provide a method of manufacturing a magnetic head comprising an efficient inductive transducing system.
A first aspect of the method according to the invention, in which a nonmagnetic, insulating material for forming a first insulation layer, on which an inductive transducing element is formed, is deposited on a plane basic surface, whereafter a nonmagnetic, insulating material for forming a second insulation layer is deposited on the first insulation layer and the inductive transducing element formed thereon, whereafter a magnetic flux guide bounding a non-magnetic gap layer adjoining the basic surface is formed, whereafter the head face is formed, whereby the flux guide and the gap layer terminate in the head face, is characterized in that, after the formation of the second insulation layer, material is removed in an area, in which the head face is formed, for forming an aperture extending through the first and the second insulation layer and reaching as far as the basic surface, whereafter a non-magnetic, insulating material for forming the gap layer is deposited in the aperture, and subsequently a soft-magnetic material for forming a first soft-magnetic layer is deposited on the gap layer, whereafter the first soft-magnetic layer is planarized to form a plane surface on which a soft-magnetic material is subsequently deposited for forming a second soft-magnetic layer which, jointly with the first soft-magnetic layer, constitutes the magnetic flux guide. When the first soft-magnetic layer is being planarized, adjoining layer parts of deposited non-magnetic insulating material are preferably planarized as well.
A second aspect of the method according to the invention, in which a non-magnetic, insulating material for forming a first insulation layer, on which an inductive transducing element is formed, is deposited on a plane basic surface, whereafter a nonmagnetic, insulating material for forming a second insulation layer is deposited on the first insulation layer and the inductive transducing element formed thereon, whereafter a magnetic flux guide bounding a non-magnetic gap layer is formed, whereafter the head face is formed, whereby the flux guide and the gap layer terminate in the head face, is characterized in that, after the formation of the second insulation layer, material is removed in an area, in which the head face is formed, for forming an aperture extending through the first and the second insulation layer and reaching as far as the basic surface, whereafter a soft-magnetic material for forming a first soft-magnetic layer is deposited in the aperture, whereafter the first soft-magnetic layer is planarized to form a plane surface on which a non-magnetic, insulating material is subsequently deposited for forming the gap layer, and subsequently a soft-magnetic material is deposited for forming a second soft-magnetic layer constituting the magnetic flux guide. When the first soft-magnetic layer is being planarized, adjoining layer parts of deposited non-magnetic insulating material are preferably planarized simultaneously.
A third aspect of the method according to the invention, in which a nonmagnetic, insulating material is deposited for forming a first insulation layer on which an inductive transducing element is formed, whereafter a non-magnetic, insulating material for forming a second insulation layer is deposited on the first insulation layer and the inductive transducing element formed thereon, whereafter a magnetic flux guide bounding a nonmagnetic gap layer is formed, whereafter the head face is formed, whereby the flux guide and the gap layer terminate in the head face, is characterized in that, prior to the formation of the first insulation layer, a soft-magnetic material is deposited on a basic surface in an area, in which the head face is formed, for forming a first soft-magnetic layer, whereafter a non-magnetic, insulating material is deposited on the first soft-magnetic layer and on adjoining parts of the basic surface for forming the first insulation layer, whereafter the inductive transducing element and the second insulation layer are consecutively formed, whereafter planarizing as far as the first soft-magnetic layer is effected to form a plane surface on which a non-magnetic, insulating material for forming the gap layer and a soft-magnetic material for forming a second soft-magnetic layer constituting the flux guide are consecutively deposited.
When using the method according to the invention, the flux guide is situated on a planarized surface extending parallel to the inductive transducing element, while the distance between this surface and the relevant transducing element can be chosen independently of a desired gap length formed by the gap layer. This means that a relatively large distance between the flux guide and the inductive transducing element desired for reasons of efficiency can be realized without any consequence for the gap length and without any extra measures. The gap length can be determined by structuring the first soft-magnetic layer when the method is being carried out.
An embodiment of the me
Draaisma Eeltje A.
Pronk Franciscus A.
OnStream Inc.
Pianalto Bernard
Welsh & Katz Ltd.
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