Embodiments of the present invention will now be described by way of examples and with reference to the accompanying drawings, in which:
Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
The thin film magnetic head of the present embodiment is used for a magnetic disk drive unit and has a read-element constituted by a magnetoresistance effect element, e.g., tunnel junction element (TMR).
A method of producing the thin film magnetic head of the present embodiment will be explained with reference to
In
Next, a tunnel junction element layer 6 is formed on the lower shielding layer 4.
In
In
In
At that time, the insulating film 10 coats a surface of the resist layer 8 too. The insulating film 10 coating the resist layer 8 acts as a protection film against etching beams in the following etching step. Namely, the insulating film 10 restrains the resist layer 8 from etching. The insulating film (the protection film) 10 is made of one substance selected from the group consisting of: Al2O3, AlN or SiO2. A thickness of the protection film is 20 nm or less. Note that, a step of forming a protection film, which is resistant to the etching, on the surface of the resist layer 8 may be further added, besides the step of forming the insulating film 10 coating the upper face of the lower shielding layer 4 and the side faces of the read-element 6a.
Next, as shown in
Next, as shown in
In the etching step, the resist layer 8 acts as a shielding wall against ion beams, so that amount of ion beams 18 colliding with the hard bias film 12 in the vicinity of the resist layer 8 (the read-element 6a) can be reduced. Etching the hard bias film 12 is relatively advanced more with distance from the resist layer 8 (the read-element 6a), so that the surface of the hard bias film 12 can be flattened.
At that time, the read-element 6a is coated with the resist layer 8 and is not exposed, so that the read-element 6a is not badly influenced by the flattening process.
In the etching step, as shown in
The incoming direction of the ion beams 18, which are irradiated toward the wafer substrate 2, is inclined with a suitable angle θ, e.g., 10 degrees or more. With this structure, even if etching dusts, which are formed by the etching step, stick onto the side faces of the resist layer 8 again, the ion beams 18 collide with the side faces of the resist layer 8 so that the etching dusts can be removed. Therefore, sticking the etching dusts in the vicinity of the read-element 6a can be restrained when the resist layer 8 is removed in the following step. By removing the etching dusts, no asperities are formed in the surfaces of the hard bias film 12 and the read-element 6a after the resist layer 8 is removed.
Further, the inclination angle θ of the incoming direction of the ion beams 18 may be varied in the etching step so as to control flatness of the hard bias film 12. If the angle θ is wide, the amount of etching the hard bias film 12 can be reduced at a position distant from the resist layer 8. By controlling the inclination angle θ on the basis of an etching position, the amount of etching the hard bias film 12 can be controlled at all positions.
Further, by controlling the thickness of the resist layer 8, the amount of etching the hard bias film 12 can be controlled. With increasing the thickness of the resist layer 8, the amount of etching the hard bias film 12 is reduced not only in the vicinity of the resist layer 8 but also at positions distant therefrom.
According to the study by the inventors, the hard bias film 12 can be suitably flattened when the thickness of the resist layer 8 is 1 μm or less, preferably 300-400 nm.
After etching the hard bias film 12, as shown in
Next, as shown in
At that time, the surface of the hard bias film 12 has been made flat, so that the separating layer 14 and the upper shielding layer 16 can be made flat. Therefore, forming magnetic walls in the upper shielding layer 16 can be restrained, and characteristics of the upper shielding layer 16 can be improved.
Unlike the conventional method, the method of the present embodiment is capable of flattening the surface of the hard bias film 12 without badly influencing the read-element 6a.
The invention may be embodied in other specific forms without departing from the spirit of essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Number | Date | Country | Kind |
---|---|---|---|
2006-174872 | Jun 2006 | JP | national |