Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-06-01
2003-03-04
Huson, Gregory (Department: 3751)
Metal working
Method of mechanical manufacture
Electrical device making
C029S603090, C029S603150, C029S603160, C029S603180
Reexamination Certificate
active
06526649
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method of a magneto-resistive effect type head formed by having a magneto-resistive effect element.
Generally, a thin film magnetic head is a magnetic head composed by laminating a magnetic film, an insulating film, and other thin films in multiple layers, and forming conductor coils, lead wires, and terminals. This thin film magnetic head is formed by vacuum thin film forming technology, and is hence characterized by ease of micronizing the dimensions such as a narrow track and narrow gap, and high resolution recording, and is noticed as a magnetic head applicable to high density recording.
For example, a thin film magnetic head for recording and reproducing information signals in and from a magnetic recording medium is composed by forming a conductor coil and a magnetic film by vacuum thin film forming technology on a substrate composed of oxide magnetic material such as ferrite.
Specifically, a preferred thin film magnetic head for recording is a so-called inductive type magnetic head.
This inductive type magnetic head is used by mounting on a hard disk drive or the like as a composite type thin film magnetic head together with, for example, a magneto-resistive effect type thin film magnetic head (MR head) for reproduction.
In this composite type thin film magnetic head, the magneto-resistive effect type thin film magnetic head (MR head) is narrowed in the width of reproduction track as the recording density becomes higher.
As one of structures of magneto-resistive effect element (MR element) for the above-mentioned MR head for reproduction, it is proposed that a magneto-resistive effect film (MR film) with magneto-resistive effect be composed of a so-called spin valve element.
The spin valve element is formed by having two ferromagnetic films be opposed to each other via a nonmagnetic film, disposing an anti-ferromagnetic layer at one ferromagnetic film side, using this ferromagnetic layer as a fixed layer being fixed in the direction of magnetization, and setting the other ferromagnetic film as a free layer freely rotating in the direction of magnetization by an external magnetic field. By rotation (spin) of this free layer in the direction of magnetization, the resistance or voltage is changed.
In the MR head using this spin valve element in the MR film, bias magnet films composed of hard magnetic films are disposed at both sides of the MR film, and a specific bias magnetic field is applied to the MR film so that the magnetic characteristic of the free layer is stabilized.
In the MR head of this structure, the width of the reproduction track is defined as the effective width of the MR film (hereinafter called a reproduction width).
When the reproduction width of the MR film becomes narrower, as compared with the case of a wide reproduction width, slight changes of the adjacent bias magnetic film and electrode film are likely to affect the characteristic (stability) of the MR head, which is estimated to be due to the shape of the junction between the MR film and bias magnet film, or the state of the electrode film.
SUMMARY OF THE INVENTION
To solve these problems, the present invention is to present a manufacturing method of a magneto-resistive effect type head capable of manufacturing a magneto-resistive effect type head with a stabilized characteristic of the head.
The manufacturing method of magneto-resistive effect type head of the invention is a manufacturing method of magneto-resistive effect type head for manufacturing a magneto-resistive effect type magnetic head composed by forming on a substratea a magneto-resistive effect element having a fixed layer composed of an anti-ferromagnetic layer and a magnetic layer thereon, a nonmagnetic conductive layer on the fixed layer, and a free layer further thereon, and forming bias magnets on both sides of the magneto-resistive effect element, comprising a step of forming a magneto-resistive effect film in a trapezoidal shape having a specified abutting angle by means of ion milling through a resist mask of overhang structure, in which the angle of ion milling is 5° or less to the normal of the substrate surface.
According to the manufacturing method of the invention, by comprising the step of forming a magneto-resistive effect film in a trapezoidal shape having a specified abutting angle by means of ion milling through a resist mask of overhang structure, in which the angle of ion milling is 5
20
or less to the normal of the substrate surface, the abutting angle of the trapezoidal magneto-resistive effect film can be set at 15° or more to the substrate surface.
The manufacturing method of magneto-resistive effect type head in another aspect of the invention is a manufacturing method of a magneto-resistive effect type head for manufacturing a magneto-resistive effect type magnetic head composed by forming on a substrate a magneto-resistive effect element having a fixed layer composed of an anti-ferromagnetic layer and a magnetic layer thereon, a nonmagnetic conductive layer on the fixed layer, and a free layer further thereon, and forming bias magnets on both sides of the magneto-resistive effect element, comprising a step of forming a magneto-resistive effect film in a trapezoidal shape having a specified abutting angle by means of ion milling through a resist mask of overhang structure, a step of forming bias magnet films for filling in sides of the trapezoidal magneto-resistive effect film, and a step of forming an electrode film to overlap partly with the magneto-resistive effect film through the resist mask, in which the angle of ion beam sputtering when forming the electrode film is 30° or less to the normal of the substrate surface.
According to the manufacturing method of the invention, by comprising a step of forming a magneto-resistive effect film in a trapezoidal shape having a specified abutting angle by means of ion milling through a resist mask of overhang structure, a step of forming bias magnet films for filling in sides of the trapezoidal magneto-resistive effect film, and a step of forming an electrode film to overlap partly with the magneto-resistive effect film through the resist mask, in which the angle of ion beam sputtering when forming the electrode film is 30° or less to the normal of the substrate surface, it becomes possible to effectively decrease invasion of the electrode film into the bottom of the resist mask of overhang structure
As a result, it becomes possible to effectively control the position of the edge of the electrode film in the width direction on the magneto-resistive effect film in a way for it to come to an outer side position, for example, to a dead magnetic zone not contributing to detection of magnetic field from a magnetic recording medium.
The manufacturing method of a magneto-resistive effect type head in another aspect of the invention is a manufacturing method of a magneto-resistive effect type head for manufacturing a magneto-resistive effect type magnetic head composed by forming on a substrate a magneto-resistive effect element having a fixed layer composed of an anti-ferromagnetic layer and a magnetic layer thereon, a nonmagnetic conductive layer on the fixed layer, and a free layer further thereon, and forming bias magnets on both sides of the magneto-resistive effect element, comprising a step of forming a magneto-resistive effect film in a trapezoidal shape having a specified abutting angle by means of ion milling through a resist mask of overhang structure, in which the anti-ferromagnetic layer is etched to a position of 30% or less of the depth at the step of forming the magneto-resistive effect film in a trapezoidal shape.
According to the invention, comprising a step of forming a magneto-resistive effect film in a trapezoidal shape having a specified abutting angle by ion milling through a resist mask of overhang structure, in which the anti-ferromagnetic layer is etched to a position of 30% or less of the depth at the step of forming the magneto-resistive effect film in a trapezoida
deVore Peter
Huson Gregory
Sonnenschein Nath & Rosenthal
Sony Corporation
LandOfFree
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