Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2002-06-17
2004-10-12
Tugbang, A. Dexter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S417000, C029S603060, C029S603070, C029S603130, C360S123090, C360S125330, C360S317000, C417S127000, C417S128000, C216S039000, C216S041000, C216S048000
Reexamination Certificate
active
06802115
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a working method of a bar block with a plurality of magnetic head sliders arranged in at least one line and to a manufacturing method of a thin-film magnetic head.
2. Description of the Related Art
Recent demand for higher recording density in a hard disk drive (HDD) apparatus makes a request of a thin-film magnetic head to have a higher sensitivity and a higher output characteristics. In order to satisfy the request, a thin-film magnetic head with a general anisotropic magnetoresistive effect (AMR) element, a thin-film magnetic head with a giant magnetoresistive effect (GMR) element utilizing, for example, a spin valve effect, and a thin-film magnetic head with a tunneling magnetoresistive effect (TMR) element are proposed and going into actual use.
When manufacturing thin-film magnetic heads with these high sensitive magnetoresistive effect (MR) elements, it is necessary to take countermeasures against breakdown of the MR elements as a result of electrostatic discharge (ESD).
A bar block obtained by dicing a wafer on which many thin-film magnetic head elements are formed has a plurality of aligned magnetic head elements. During machining of this bar block (slider working), it will be necessary to take countermeasures against an ESD-breakdown.
Conventionally, as a countermeasure against an ESD-breakdown during a slider working, electrode terminals or bonding pads electrically connected to an MR element are short-circuited by an electrically conductive ball such as an Au ball. After the slider working, the conductive ball is removed from the bonding pads.
However, the bonding process of the conductive balls between the bonding pads is very complicated, and also when the conductive ball for short-circuiting the bonding pads is removed after the slider working, damage may often occur at these bonding pads.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a working method of a bar block and a manufacturing method of a thin-film magnetic head, whereby countermeasures against an ESD-breakdown can be easily taken.
Another object of the present invention is to provide a working method of a bar block and a manufacturing method of a thin-film magnetic head, whereby countermeasures against an ESD-breakdown can be taken without causing damage to bonding pads for a magnetic head element.
According to the present invention, a working method of a bar block with a plurality of magnetic head elements and a plurality of pairs of electrode terminals electrically connected to the plurality of magnetic head elements arranged on an element-formed surface of the bar block in at least one line is provided. This method includes a step of pre-laminating an anisotropic conductive film (ACF) on the element-formed surface of the bar block, a step of bonding a conductive plate member with a plurality of projections located at positions faced to the plurality of pairs of terminal electrodes of the bar block, respectively, on the ACF so that each pair of the terminal electrodes is electrically short-circuited with each other, and a step of, then, working the bar block.
Also, according to the present invention a manufacturing method of a thin-film magnetic head, includes a step of forming by a thin-film fabrication method many of magnetic head elements and many pairs of electrode terminals electrically connected to the many of magnetic head elements on an wafer, a step of dicing the wafer to form a plurality of bar blocks each having a plurality of the magnetic head elements and a plurality of pairs of the electrode terminals electrically connected to the plurality of magnetic head elements arranged on an element-formed surface of the bar block in at least one line, a step of pre-laminating an ACF on the element-formed surface of the bar block, a step of bonding a conductive plate member with a plurality of projections located at positions faced to the plurality of pairs of terminal electrodes of the bar block, respectively, on the ACF so that each pair of the terminal electrodes is electrically short-circuited with each other, a step of, then, working the bar block, and a step of cutting the bar block into separated individual thin-film magnetic heads.
An ACF is pre-laminated on an element-formed surface of a bar block and a conductive plate member with projections located to face the respective terminal electrodes of the bar block is bonded on the ACF with a temperature and a pressure. Thus, a short-circuit from one terminal electrode, through the ACF, the projection of the conductive plate member, the body of the conductive plate member, the projection of the conductive plate member and the ACF to the other electrode terminal is formed. Under this short-circuited state, the bar block can be worked.
Because the electrical short-circuit can be achieved only by pre-laminating the ACF on the element-formed surface of the bar block and by bonding the conductive plate member on the ACF with a temperature and a pressure, countermeasures against an ESD-breakdown can be easily taken. Also, the conductive plate member can be easily detached by removing the ACF without causing damage to bonding pads for a magnetic head element. Furthermore, because the ACF covers the entire element-formed surface of the bar block, this surface can be effectively protected during slider working.
It is preferred that the method further includes a step of removing the anisotropic conductive film and the conductive plate member from the bar block after performing the working step of the bar block but before performing the cutting step.
It is also preferred that the removing step includes removing the anisotropic conductive film from the bar block by using a solvent.
It is further preferred that the plurality of magnetic head elements include a plurality of MR elements.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.
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“DC resistance instability in magnetoresistive recording heads”; Du, S.X.; Villaume, G.M.; Henderson, M.R.; Magnetics, IEEE Transactions on, vol. 36, Issue: 5, Sep. 2000 pp.:2493-2495.
Miyagawa Koichi
Shiraishi Masashi
Kim Paul
SAE Magnetics (H.K. ) Ltd.
Tugbang A. Dexter
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