Metal working – Means to assemble or disassemble – Means to assemble electrical device
Reexamination Certificate
2001-12-11
2004-07-06
Trinh, Minh (Department: 3729)
Metal working
Means to assemble or disassemble
Means to assemble electrical device
C029S729000, C029S721000, C029S423000, C029S603120, C029S603160, C451S005000
Reexamination Certificate
active
06757964
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for manufacturing sliders used for a thin-film magnetic head and the like.
2. Description of the Related Art
A flying-type thin-film magnetic head used for a magnetic disk device and so on is generally made up of a thin-film magnetic head slider (that may be simply called a slider) having a thin-film magnetic head element provided at the trailing edge of the slider. The slider generally comprises a rail whose surface functions as a medium facing surface (an air bearing surface) and a tapered section or a step near the end on the air inflow side. The rail flies slightly above the surface of a recording medium such as a magnetic disk by means of air flow from the tapered section or step.
A thin-film magnetic head element generally used is a composite-type element made up of layers of an induction magnetic transducer for writing and a magnetoresistive (MR) element for reading.
In general, such thin-film magnetic head sliders are formed through cutting a wafer in one direction in which sections to be sliders (called slider sections in the following description) each including a thin-film magnetic head element are arranged in a plurality of rows. A block called a bar in which the slider sections are arranged in a row is thereby formed. Rails are then formed in the bar and the bar is cut into the sliders.
The manufacturing process of the sliders includes a step of processing the medium facing surface of the bar, that is, grinding or lapping the medium facing surface and a step of cutting the wafer into the bars. The order of the step of processing the medium facing surface and the step of cutting the wafer into the bars depends on methods of processing the medium facing surface and cutting the wafer, as described later.
In the step of processing the medium facing surface, it is required that the MR height and the throat height of the thin-film magnetic head element formed in the bar each fall within a tolerance range and that processing accuracy of the surface processed falls within a tolerance range. The MR height is the length (height) between the end of the MR element close to the medium facing surface and the opposite end. The throat height is the length (height) of the magnetic pole of an induction magnetic transducer.
In related art the following method is generally taken to process the medium facing surfaces of the bars and cutting the wafer into the bars. That is, a bar including a row of slider sections is cut from a wafer. The bar is fixed to a specific jig by bonding the surface of the bar opposite to the medium facing surface to the jig. The medium facing surface of the bar thus fixed to the jig is then processed. This method is called a first method in the following description.
In related art, second and third methods described below have been proposed, in addition to the first method, for processing the medium facing surfaces of the bars and cutting the wafer into the bars.
The second method is, as shown in
FIG. 7
of U.S. Pat. No. 5,406,694, for example, a specific length of block including rows of slider sections is cut from a wafer. The block is fixed to a specific jig by bonding the surface of the block opposite to the medium facing surface to the jig. The medium facing surface of the block thus fixed to the jig is then processed. The block is then cut into bars whose medium facing surfaces have been processed.
The third method is, as shown in
FIG. 3
of Japanese Patent Application Laid-open Hei 4-289511, for example, a wafer is fixed to a specific jig and the medium facing surface of the wafer fixed to the jig is processed. The wafer is then cut into bars whose medium facing surfaces have been processed.
Of the foregoing methods, in the first method a bar including a row of slider sections is cut from a wafer. The bar is fixed to a jig and the medium facing surface of the separated bar is then processed. Consequently, the bar is often affected by the state of the interface between the bar and the jig or by warpage caused by bonding and likely to be deformed and to form a curvature and the like. As a result, it is likely that processing accuracy of the surface of the bar processed is reduced and deformation occurs, such as curvatures of the layers making up the thin-film magnetic head elements formed in the bar. In addition, it is difficult to precisely control the resistance of the MR element, the MR height and the throat height. It is therefore difficult to precisely fabricate thin-film magnetic head sliders with excellent properties.
In contrast, the second and third methods do not include the step of fixing a separate bar sliced from a wafer to the jig. Therefore, the above-stated problems are reduced. In the second and third methods, however, the medium facing surface is processed and then the wafer or block is cut into bars while the medium facing surface is exposed. Consequently, the pole portions may be eroded by a water-soluble grinding agent, dust may deposit on the medium facing surface, and mechanical scratches may result on the medium facing surface when the wafer or block is cut into bars. Furthermore, the bar may be chipped while handled after the bar is sliced from the wafer. It is therefore difficult to precisely fabricate thin-film magnetic head sliders with excellent properties.
Another method for overcoming the foregoing problems is to bond a dedicated jig to the medium facing surface of a wafer or a block with a binder such as a thermosetting resin or a thermoplastic adhesive. In this method, however, it is required that every time the wafer or block is sliced, the medium facing surface of the wafer or block is bonded to the jig before slicing, and the bar is detached from the jig after slicing. These bonding and removing make the manufacturing process complicated and require extra time, and the production efficiency is reduced. The method further has a problem that binder residues (adhesive transfer) are left on the medium facing surface and the cleaning ability (the cleaning efficiency and the state after cleaning) are not satisfactory. In addition, since it is required that the bar is removed from the jig after slicing, automation of the processing performed on the sliced bar is difficult.
The third method requires steps of fixing the wafer to the jig and separating the wafer from the jig every time the bar is sliced. The manufacturing process is therefore complicated and the production efficiency is reduced.
In related-art methods of manufacturing sliders, human handling and so on may cause static damage to the sliders and the thin-film magnetic head elements formed in the sliders, in particular.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method and an apparatus for manufacturing sliders having excellent properties with accuracy and for improving the production efficiency and the cleaning property.
A method of manufacturing sliders of the invention is provided for fabricating a slider aggregate that is made from a material including a plurality of rows of sections to be the sliders each having a medium facing surface. The slider aggregate includes one of the rows of the sections to be the sliders whose medium facing surfaces receive a specific processing. The method includes the steps of: performing the specific processing on the medium facing surfaces of the row of the sections to be the sliders located at one end of the material; and cutting the material while the medium facing surfaces are covered with a strip-shaped protection member such that the row of the sections to be the sliders whose medium facing surfaces have received the specific processing are separated from the material to be the slider aggregate.
In the method of manufacturing sliders of the invention, the specific processing is performed on the medium facing surfaces of the row of the sections to be the sliders located at one end of the material in the step of performing the processing. The material is cut while the medium facing
Harada Tatsuya
Nakata Kunimasa
Sasaki Yoshitaka
Oliff & Berridg,e PLC
TDK Corporation
Trinh Minh
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