Etching a substrate: processes – Mechanically shaping – deforming – or abrading of substrate
Reexamination Certificate
2000-06-14
2003-07-08
Gulakowski, Randy (Department: 1746)
Etching a substrate: processes
Mechanically shaping, deforming, or abrading of substrate
C216S002000, C216S022000, C216S065000, C216S052000, C216S066000, C216S067000, C219S121690, C219S121730, C360S235400, C360S318100, C029S603120
Reexamination Certificate
active
06589436
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates in general to a method of adjusting the flatness, i.e., the crown and camber, of a slider using a selective plasma etching process. More particularly, the present invention is a method of selectively etching substrate chemical species from the surface of a slider, wherein selectively etching one species relative to another species on the slider surface will adjust the amount of crown and/or camber to the slider and hence, adjust the flatness of the slider.
2. Description of the Related Art
Magnetic head assemblies that “floats” or “flies” relatively to magnetic medium have been used extensively, and these assemblies are commonly referred to as magnetic head sliders. These assemblies provide a traducing relationship between a magnetic transducer and a magnetic recording medium, such as a rotating magnetic disk, so that a stable constant spacing can be maintained between the transducer and the disk. In magnetic recording technology it is continually desired to improve the aerial density at which information can be recorded and reliably read. This desire has lead to a trend toward greater bit density along the magnetic recording track and a shrinking track width. Another change that is usually required is a lower flying height, so it becomes more difficult to maintain the lower flying height constant to the degree required to reliably record and read data at the higher data rates.
The prior art process for making a magnetic head slider involves a lapping process in which the air-bearing surface (ABS) is defined and a subsequent process in which a pattern of rails is produced on the ABS. For example, U.S. Pat. No. 4,912,883 describes a lapping system in which the magnetic head assembly includes an inductive read/write head, and U.S. Pat. No. 4,914,868 describes a lapping system in which the magnetic head assembly includes a magneto-resistive write transducer. The pattern of rails can be produced by etching, ion milling, or other machine techniques, or by laser ablation as described in U.S. Pat. No. 4,301,353.
The prior art processes for making a magnetic head slider produce substantial stresses on the slider. The resulting distortion produces a concave surface on the lapped ABS surface which leads to negative crown and camber. Negative crown and camber can make it more difficult to meet the desired design requirements since the flying height is strongly affected by crown and camber. The prior art discloses several methods of correcting the flatness of a slider. U.S. Pat. No. 5,266,769 discloses a method of adjusting the flatness, i.e., the crown and/or camber, of a slider, wherein the lapped slider is exposed to a selective laser ablation process, whereby each slider is individually treated, typically on its flex side. On the flex side of sliders, laser ablation produces pits and grooves (1-10 micrometers deep) that allows for slider bowing towards ABS to create a positive crown. One drawback of the laser ablation method is that sliders are processed one at a time, which makes this method a low through-put process. Other similar methods can also be used such as micro-sandblasting.
What is needed is an improved method of adjusting the flatness of the slider which has a larger through-put and higher efficiency. The present invention is directed towards the use of selective reactive etching (otherwise known as reactive ion etching or RIE) to adjust the crown and camber of a slider.
SUMMARY OF THE INVENTION
It is therefore one object of the present invention to provide an improved method of altering the crown and camber (the “flatness”) of a slider.
It is another object of the present invention to provide a batch method of altering the crown and camber of a slider, whereby a row of sliders can be processed simultaneously, thus allowing from 10,000 to 100,000 sliders to be processed in several minutes.
It is another object of the present invention to provide a method of altering the crown and camber of a slider that diminishes the possibility of contaminating the slider surface.
The foregoing objects are achieved by providing a reactive ion etching (RIE) method of altering the flatness of a slider, whereby a slider or row of sliders is placed within a RIE apparatus. The apparatus comprises essentially an electrode within a chamber having an inlet and an outlet. The electrode is controlled by a bias power source. A source power is provided to the chamber to generate the plasma, wherein a gas or gas mixture is first introduced into the chamber and the source power is adjusted to maximize the plasma composition of ions and reactive neutral species. The ions and reactive neutral species are generated from reactive chemical species such as CHF
3
and other F-containing species. An inert gas such as Argon may also be present as a mixture with the reactive chemical species.
The bias power is adjusted to control the bombardment energy of the ions in the plasma, while the reactive neutral species react selectively with substrate species, thus leaving pits and craters in the exposed slider surface. These pits and craters thus effectuate a change in the crown and camber of the slider. Preferably, a positive crown and camber is generated in the slider(s). Also preferably, the flex-side of the slider is the exposed side of the slider. Further, in one preferred embodiment, the slider is made from Al
2
O
3
and TiC, the TiC being selectively etched relative to the Al
2
O
3
material, thus effectuating the adjustment of the slider flatness.
The above as well as additional objectives, features, and advantages of the present invention will become apparent in the following detailed written description.
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Campbell Richard T.
Fox Ciaran A.
Hsiao Richard
Hsiao Yiping
Tabib Jila
Bracewell & Patterson L.L.P.
Gulakowski Randy
Martin Robert B.
Winter Gentle
LandOfFree
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