The present invention relates to a method of manufacturing a head slider, more precisely relates to a method of manufacturing a head slider, in which a row bar cut from a wafer substrate is uniquely processed.
In a head slider of a magnetic storage unit, step-shaped sections, i.e., an air bearing surface (ABS) section(s) and a step section(s), are formed in a facing surface, which faces a surface of a recording medium, thereby the head slider can be floated from the surface of the recording medium by an air stream, which is generated by rotation of the recording medium. Step-shaped sections of head sliders have different configurations. In some head sliders, step-shaped sections have different heights.
An example of a head slider having step-shaped sections, whose heights are different, is shown in
A sensor 12, which includes a read-element and a write-element, is formed on a side face of the substrate 11, which is perpendicular to the facing surface of the head slider 10. The sensor 12 is constituted by thin films so as to form the read-element, etc. on a wafer substrate.
The ABS sections 14a and 14b, the step sections 15a and 15b, and the groove surface 16 are formed by the steps of: laminating films on the wafer substrate; cutting a row bar from the wafer substrate; abrading a surface of the row bar, which will face the recording medium; and ion-milling the abraded surface of the row bar so as to form the step-shaped sections.
The conventional method is disclosed in, for example, Japanese Laid-open Patent Publications No. 2005-276284 and No. 2002-373477.
However, the conventional method of manufacturing a head slider has following problems. Namely, when the step-shaped sections are formed in the facing surface of the head slider, the head slider is ion-milled, so burrs will stick onto the facing surface and will damage the recording medium.
The production process of the head slider includes steps of abrading and cutting the ALTIC substrate, so particles of the ALTIC material, which fall from a tip or a crack formed while processing the wafer substrate, invade into a clearance between the head slider and the recording medium. Therefore, disk crush will be caused during the operation.
Heights of the ABS sections and the step sections are fixed, but a relative rotational speed of the recording medium with respect to the head slider is varied depending on positions of the head slider with respect to the recording medium, e.g., a position facing a center part of the recording medium, a position facing an outer part of the recording medium. Therefore, an amount of floating the head slider from the recording medium varies.
To restrain the variation of the amount of floating the head slider, a dynamic flighing height (DFH) method, in which a heater circuit is formed in the sensor and a clearance between the sensor and the recording medium is adjusted by thermal expansion of a thermal expansion material of the sensor which is controlled by passing an electric current through the heater circuit, is proposed. However, the heater circuit is located close to the sensor, so the heat will badly influence characteristics of the sensor.
The heater circuit may be formed in the ABS of the head slider, but the head slider or the sensor is located close to the recording medium and the disk crush will be occurred.
The present invention was conceived to solve the above described problems.
An object of the present invention is to provide a method of manufacturing a head slider, which is capable of improving a floating characteristic and an electromagnetic conversion characteristic of the head slider and preventing a recording medium from being damaged by burrs, etc. stuck on a surface of the head slider.
To achieve the object, the present invention has following constitutions.
Namely, the method of manufacturing a head slider comprises the steps of: forming terminals on a leading end face of a row bar, to which an air inflows; forming a resist pattern, which corresponds to a configuration of an air bearing surface (ABS) section to be formed on a facing surface of the row bar, which will face a storage medium; partially thinning the facing surface of the row bar until reaching a groove surface, with using the resist pattern as a mask, so as to form the ABS section; forming a base layer of a step section on the groove surface; forming a heater circuit, which is electrically connected to the terminals, on the base layer; and coating the base layer, on which the heater circuit has been formed, with a thermal expansion material layer so as to form the step section.
In the method, the base layer of the step section may be formed on the groove surface after forming the ABS section, the heater circuit may be formed on the base layer, and the base layer, on which the heater circuit has been formed, may be coated with the thermal expansion material layer. With this method, the heater circuit can be formed in the ABS section.
The method may further comprise the step of finish-abrading an ABS of the ABS section, which is performed after forming the ABS section and the step section. With this method, the ABS can be accurately formed.
The method may further comprise the steps of: cutting the row bar, which is supported by a supporting jig, to form the head slider after forming the ABS section and the step section; and finish-abrading an ABS of the head slider, which is supported by the supporting jig.
The method may further comprise the steps of: cutting the row bar, which is supported by a supporting jig, to form the head slider after forming the ABS section and the step section; and coating an outer surface of the head slider, which is supported by the supporting jig, with a protection film. With this method, the head slider including the outer surface can be coated with the protection film.
By employing the method of the present invention, the heater circuit is formed in the step section, so that a height of the step surface can be adjusted by controlling thermal expansion of the step section. Height variation of the step surface, which is caused in the steps of processing the head slider, can be absorbed, so that characteristics of the head slider can be improved.
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.
(Basic Steps of Manufacturing Head Slider)
Basic steps of manufacturing a head slider will be explained with reference to
In
In
Generally, the ABSs and the sensors are finish-abraded, in the abrading step, to have the prescribed size. On the other hand, in the method of the present invention, the ABSs are finish-abraded and the sensors are finally positioned in the following step. Therefore, an abrasive margin, which will be removed in the finish-abrading step, is left in this abrading step.
After completing the abrading step, the outermost row bar 27 of the stack bar 24 is cut from the stack bar 24 and set on a setting plate 28 composed of an electrically conductive ceramic (see
A cut surface of the stack bar 24 is abraded every time the row bar 27 is cut from the stack bar 24, and then the new outermost row bar 27 is cut from the stack bar 24. This process is repeated, and the row bars 27 cut from the stack bar 24 are set on the setting plate 28 in order (see
Next, ABS sections and step sections of the row bars 27 are formed in the sate in which the row bars 27 are set on the setting plate 28. The ABS sections and the step sections formed in the abraded surfaces of the row bars 27 are shown in
In
(Characteristic Steps of Manufacturing Head Slider)
The above described production steps shown in
In
Ends of the heater circuits will be connected to end faces of the terminals 32, which are parallel to an abraded surface (a facing surface) 20b of the row bar 27, in the step of forming the heater circuits. Therefore, the terminals 32 are formed at suitable positions, at which the ends of the heater circuits can be easily connected to the terminals 32 in the step of forming the heater circuits.
Note that, the terminals 32 may be formed in the LE surface of the row bar 27 by performing the sputtering from the abraded surface side of the row bar 27. To easily form the terminals 32, the resist pattern is formed on the LE surface of the row bar 27 and the sputtering is performed from the LE surface side.
In
In
In
The conventional method of manufacturing the head slider, which has the ABS sections and the step sections, comprises the steps of: ion-milling outer regions of the ABS sections until reaching step surfaces; coating the ABS sections and the step sections with resist; and ion-milling outer regions of the step sections until reaching the groove surface. The ion milling is performed twice for forming the ABS sections, the step sections and the groove surface. On the other hand, the present embodiment is characterized in that the ion milling is performed, beyond the step surfaces, until reaching the groove surface 16 when the ABS sections 14a and 14b are formed.
Note that, when the resist patterns 36a and 36b are formed, the terminals 32 are coated with the resist pattern 36a so as to protect the terminals 32 while performing the ion milling. The resist pattern 36b is patterned so as to coat and protect the sensor of the element section 22.
In the present embodiment, the ABS sections 14a and 14b are separately formed on the element section 22 side and on the terminal 32 side. The ABS sections 14a and 14b can be optionally formed by patterning the resist.
In
In the present embodiment, the heater circuits will be formed in the step sections 15a and 15b. In this case, preferably, the base layer 38a and 38b are composed of a low-thermal expansion material so as to restrain heat conduction from the heater circuits to the base member 20a. In case of forming the heater circuit, the base layers 38a and 38b are composed of an electrically insulating material, e.g., alumina, so as to electrically insulate from the base member 20a.
Note that, in case of forming no heater circuits in the step sections 15a and 15b, the base layers 38a and 38b may be composed of a good heat conductive material, e.g., metal, or an electrically conductive material. In this case, the base layers 38a and 38b themselves act as the step sections 15a and 15b.
The base layers 38a and 38b are formed by the steps of: coating the surface of the row bar 27 including the groove surface 16 with resist; patterning the resist to form opening sections corresponding to the base layers 38a and 38b; and filling the opening sections with the material of the base layers 38a and 38b, e.g., alumina, by sputtering. In
In the present embodiment, the heater circuits 40 are formed in the step sections 15a and 15b, so the heater circuits 40 are patterned on the surfaces of the base layers 38a and 38b after forming the base layers 38a and 38b. The heater circuits 40 are formed by the steps of: coating the base layers 38a and 38b with resist; patterning the resist according to configurations of the heater circuits 40; and filling the resist patterns with an electrically conductive material, e.g., Ti, Ta, by sputtering. By forming the thin and winding heater circuits 40 on the surfaces of the base layers 38a and 38b with a suitable electrically conductive material, desired heater circuits can be formed. In
The ends of the heater circuits 40 are electrically connected to the terminals 32. When the resist patterns for forming the heater circuits 40 are formed, the resist patterns are designed to extend the ends of the heater circuits 40 until reaching the end faces of the terminals 32. Since the end faces of the terminals 32, which will face a recording medium, are exposed, the heater circuits 40 can be electrically connected to the terminals 32 by sputtering the electrically conductive material after forming the resist patterns.
In the present embodiment, the ABS sections 14a and 14b are formed between the step sections 15a and 15b. Therefore, the base layers 38a and 38b are formed on the both sides of the ABS sections 14a and 14b. The heater circuits 40 are respectively formed on the base layers 38a and 38b, and the heater circuits 40 are respectively connected to the terminals 32. Each of the heater circuits 40 is connected to the plus terminal 32 and the minus terminal 32, so the heater circuits 40 are connected to four of the terminals 32.
After forming the heater circuits 40, the base layers 38a and 38b are coated with thermal expansion material layers 42a and 42b, and the heater circuits 40 are encased therein as shown in
For example, the thermal expansion material of the thermal expansion material layers 42a and 42b is TiW. In case that the thermal expansion material layers 42a and 42b are composed of an electrically conductive material, insulating layers are provided to the thermal expansion material layers 42a and 42b.
The surfaces of the thermal expansion material layers 42a and 42b become the step surfaces, i.e., an outer surface of the head slider, so the thermal expansion material must be selected in consideration of corrosion resistance and lubricity to the recording medium. Outermost layers of the thermal expansion material layers 42a and 42b may be composed of a material having enough corrosion resistance, and a plurality of metal layers, which are composed of high-thermal expansion metals, and insulating layers may be formed in the thermal expansion material layers 42a and 42b as inner layers.
Since the outer surfaces of the step sections 15a and 15b define the step surfaces, thicknesses of the base layers 38a and 38b and the thermal expansion material layers 42a and 42b are suitably controlled in the forming steps so as to correctly set heights of the step surfaces with respect to the groove surface 16.
In
In
In the present embodiment, the ABS section 14a is formed between the step sections 15a and 15b. Therefore, six terminals 32 are formed for the heater circuits 40 and 41 of the step sections 15a and 15b and the ABS section 14a, and they are positioned close to the step sections 15a and 15b and the ABS section 14a.
In the present embodiment, the heater circuit 41 is formed in the ABS section 14a located close to the LE surface so as not to badly influence the sensor of the element section 22. If the heater circuit 41 does not badly influence the sensor of the element section 22, a heater circuit may be formed in the ABS section 14b located close to the element section 22.
In the present embodiment, the heater circuit 41 is formed in the ABS section 14a after forming the heater circuits 40 in the step sections 15a and 15b. These steps may be reverse-sequentially performed.
Further, in the present embodiment, the heater circuits are formed in the the ABS section 14a and the step sections 15a and 15b, but the heater circuits may be formed in only the ABS section(s) or the step sections.
As shown in
Next, the separated head sliders 30 adhered on the ceramic tool 29 are abraded, by an abrasive plate 26, until the ABSs reach the prescribed height. Simultaneously, the sensors in the element sections 22 are finish-abraded until reaching the prescribed size. By finish-abrading the ABSs in the following step, the height of the ABSs can be accurately controlled. In case that the heater circuit 41 is formed in the ABS section 14a like the present embodiment, the ABSs can be highly flattened and the height thereof is accurately defined by the finish-abrading step.
The finish-abraded head slider 30 is shown in
In the production steps, burrs will be formed while performing the ion milling and the cutting works, and they will stick onto the surfaces of the head sliders 30. By abrading the ABSs of the separated head sliders 30, burrs and foreign substances projected form the ABSs can be removed, so that the flat ABSs can become outermost layers of the head sliders 30. Therefore, damaging the recording medium by burrs, etc. stuck on the ABS can be prevented.
In
After coating the outer surfaces of the head sliders 30 with the protection films 46, the head sliders 30 are peeled from the ceramic tool 29, so that the independent head sliders 30 can be obtained as products.
The step sections 15a and 15b are constituted by the base layers 38a and 38b, the heater circuits 40 and the thermal expansion material layers 42a and 42b. The ABS section 14a is constituted by the base member composed of ALTIC, the base layer 38c formed in the concave part, the heater circuit 41 and the thermal expansion material layer 44.
In the present embodiment, the height difference between the ABS and the step surfaces is about 0.1-0.2 μm, and the height difference between the groove surface 16 and the step surfaces is 1-2 μm. The height differences may be optionally designed according to products.
In case of mounting the head slider 30, which has been produced by the method of the above described embodiment, on a head suspension, the sensor of the element section 22 is electrically connected to a read/write control circuit, and the terminals of the heater circuits 40 and 41 are electrically connected to a heater control circuit. By the heater control circuit, the thermal expansion of the ABS section 14a and the step sections 15a and 15b can be controlled, so that the heights of the ABS and the step surfaces can be controlled.
In the production method of the present embodiment, the heater circuits 40 and 41 can be easily formed in the the ABS section 14a and the step sections 15a and 15b, and the heights of the ABS and the step surfaces can be controlled, so that height variation of the ABS and the step surfaces can be absorbed and the head slider having a superior electromagnetic conversion characteristic can be produced.
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 |
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2008-074435 | Mar 2008 | JP | national |