Abrading – Precision device or process - or with condition responsive... – With indicating
Reexamination Certificate
2001-09-10
2004-04-20
Morgan, Eileen P. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
With indicating
C451S011000, C451S041000, C451S078000, C029S603160
Reexamination Certificate
active
06722947
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a lapping machine, a lapping method and a magnetic head manufacturing method and, more particularly, a lapping machine and a lapping method capable of working a work with high precision, and a magnetic head manufacturing method using the lapping method.
BACKGROUND ART
In case the slider equipped with the magnetic head is formed, normally such slider is formed via the steps of forming a plurality of magnetic heads in a matrix fashion on a substantially disk-like substrate, then dividing the substrate into a plurality of pieces to form Bar-like (stripe-like) works, then shaping the works, and then dividing the works into chips every magnetic head. The chip-like substrate is employed as the slider.
In the steps of shaping the work, steps of forming a rail surface for the slider and lapping a part of the work are contained. The bar-like work is also called a “row bar” on which at least the magnetic heads are aligned.
The lapping of the work is carried out to adjust a height of a magneto-resistive layer constituting the magnetic head and a height of the gap layer. Since the precision in the order of submicron unit is required for the height of the magneto-resistive layer or the gap layer, capable of working the work with high precision is needed.
In case the magnetic head is lapped, the lapping machine as set forth in Patent Application Publication (KOKAI) Hei 10-286765, for example, is employed.
As shown in
FIG. 1
, in case the work is lapped by the lapping machine, the work
101
is fitted to a lower surface of a lapping jig
102
in the situation that a top end of the magnetic head (not shown) on the work
101
is directed downward, and then the lapping jig
102
is fitted to an adaptor
103
. Then, top ends of the work
101
and the magnetic head are lapped by a lapping surface plate
104
. The work
101
is pushed against the lapping surface plate
104
by a pressure machine
105
via the adaptor
103
and the lapping jig
102
. In addition, because the camber is generated in many works
101
, all the magnetic heads on the work
101
are seldom brought into contact with an upper surface of the lapping surface plate
104
under the same conditions. For this reason, a lower end of the lapping jig
102
is pushed against the lapping surface plate
104
by one or three bending arms
106
that are passed through an opening
102
a
provided in the center of the lapping jig
102
, and then a distribution of the pushing force to the lapping surface plate
104
on work
101
is adjusted by changing the pushing force, whereby the camber of the work
101
with respect to the upper surface of the lapping surface plate
104
is corrected.
Meanwhile, as shown in
FIG. 1
, in order to correct the camber of the work
101
by using one or three bending arms
106
, top end positions of a plurality of magnetic heads being aligned on the work
101
must be successively changed along the work
101
, as shown in FIG.
2
. In other words, in the case of the state as shown in
FIG. 2
, the use of the bending arm
106
makes it easy to uniformize the lapping of a plurality of magnetic heads on the work
101
. If the lapping of the top ends of the magnetic heads is carried out uniformly, characteristics of the lapping heads become constant.
However, in case the top ends of a plurality of magnetic heads aligned on the work
101
are arranged discontinuously as shown in FIGS.
3
(
a
),
3
(
b
), it is difficult to correct the camber of the work
101
by using the bending arm
106
. Thus, the characteristics of the magnetic heads on the work
101
after the lapping do not become uniform.
Such camber of the work
101
is generated by several causes. As the causes, for example, there are the alignment error generated when a plurality of magnetic heads are formed on one substrate by the thin film growing technology, or the alignment error of the mask employed to pattern the thin film on the substrate, or the minute undulation of the cutting surface generated when the works
101
are formed by cutting the circular substrate, or the chips generated by cutting the substrate, or the flatness difference of the work contact surface of the lapping jig
102
, or the fine dusts that are present between the work
101
and the lapping jig
102
, etc.
Also, as another problem, when the crown, the camber, or the twist, as shown in FIGS.
4
(
a
) to
4
(
c
), is generated in the shape after the work
101
is lapped, variation in a floating amount of the sliders obtained by dividing the work
101
or deterioration of the characteristics of the magnetic head is caused.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a lapping machine and a lapping method capable of lapping a work while correcting appropriately a camber of the work, and a method of manufacturing a magnetic head slider using the lapping method.
The above subject can be overcome by providing a lapping machine which comprises a lapping surface plate rotated by a rotating mechanism, a lapping jig having a plurality of projections to bottom surfaces of which a work to be lapped by a lapping surface on the lapping surface plate is fitted, variation-of-projection adjusting elements for adjusting the variation of the plurality of projections to the lapping surface plate individually, and a control circuit for outputting variation-of-projection control signals to the variation-of-projection adjusting elements.
In the lapping machine, preferably a plurality of resistive elements which are lapped by the lapping surface of the lapping surface plate are fitted to the work, and the control circuit has a function for calculating resistance values of the plurality of resistive elements.
Also, the above subject can be overcome by providing a lapping method which comprises the steps of fitting a bar-like work, which is lapped by a lapping surface of the lapping surface plate, to bottom surfaces of a plurality of projections of a lapping jig, adjusting a variation of the projections by variation-of-projection adjusting elements individually, and lapping the work by the lapping surface.
In the lapping method, preferably the work is separated between the projections before lapping of the work.
In the lapping method, preferably resistive elements arranged on the projections respectively are formed on the work, and resistance values of a plurality of resistive elements are measured, and then the variation-of-projection of the projections is increased as a resistance value is smaller.
According to the lapping machine and the lapping method of the present invention, a plurality of projections are provided to the lapping jig, the work is fitted to bottom surfaces of the projections, and a variation of the projections is adjusted individually. Therefore, discontinuous positional displacement of the work can be corrected at a plurality of locations individually by changing a variation of a plurality of projections individually, and thus the camber of the work can be corrected with good precision.
Also, in the case that the work is divided into a plurality of pieces finally, the operability can be improved if the projections are provided in the same number as the division and then the work is divided at spaces between a plurality of projections before or after the lapping of the work.
In addition, if the resistive elements are formed on the work, resistance values of the resistive elements are changed in compliance with the lapping of the resistive elements. Therefore, it is possible to grasp easily the lapping progress situation and the amount of camber by detecting the resistance values of all the resistive elements. Then, if a variation of the projections is changed based on the variation in magnitude of the resistance values of the resistive elements by the lapping, it is possible to render the amount of lapping of the work to coincide with the target value by making uniform the resistance values of the resistive elements.
Further, the above subject can be overcome by providing a magnetic head manufact
Nishioka Teruaki
Sone Shunsuke
Sudo Koji
Sugiyama Tomokazu
Yanagida Yoshiaki
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