Abrading – Machine – Rotary tool
Reexamination Certificate
1998-12-04
2001-07-03
Ostrager, Allen (Department: 3725)
Abrading
Machine
Rotary tool
C451S006000, C451S041000, C451S288000
Reexamination Certificate
active
06254465
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of machining a wafer for making filmed head sliders and a device for machining said wafer, and more precisely relates to a method of lapping or polishing said wafer during a process of forming film layers thereon and a device for lapping or polishing said wafer.
The filmed head slider is made by the steps of: forming a plurality of film layers on a wafer, which is a substrate; and forming various fine patterns in the film layers by etching, etc. In the forming step, a plurality of the film layers are piled on the wafer, so there are formed undulated parts, uneven parts, step-formed parts, etc. on the filmed surface of the wafer. If the film layers are piled with the undulated parts, etc., shapes and measurements of products will be badly influenced.
These days, recording media are made smaller in size but they have large capacity of memory, so the head sliders are required to be highly precisely machined. As described above, if there are undulated parts, etc., formed on the surface of the wafer, measurements of products are badly influenced and yield thereof is also reduced. Thus, the surface of the wafer is lapped or polished so as to remove the undulated parts, etc. and uniformly finish the whole surface thereof.
In the ordinary lapping or polishing step, the wafer is mounted on a machining plate (a lapping plate or a polishing plate), a prescribed pressure is applied to the wafer, and the surface is lapped or polished by the machining plate. However, lapping or polishing is advanced much in the vicinity of an outer edge of the wafer, so lapping or polishing cannot be uniformly executed on the wafer.
A conventional method of uniformly lapping the wafer with a partial load will be explained with reference to
FIG. 7. A
wafer
12
, which is mounted on a machining plate
10
, is pressed by a work presser
14
. The work presser
14
is properly shifted from a center of the wafer
12
, so the partial load is applied to the wafer
12
. By using the partial load method, the film layers
16
on the surface of the wafer
12
can be uniformly lapped by the machining plate
10
. However, this method cannot always selectively lap uneven parts, and bad wafers are sometimes produced because of excessive lapping by the partial load.
A substrate of the wafer is sometimes bent, and the wafer is sometimes slightly bent while forming the film layers and etching the film layers. In this case, the bend of the wafer must be corrected by force while lapping. However, excessive force sometimes peels off the film layers and deforms end faces of element sections.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method of machining a wafer for making filmed head sliders and a device for machining said wafer, which are capable of precisely lapping or polishing the wafer while the process of forming the film layers, increasing the yield of making the filmed head sliders and increasing the reliability thereof.
To achieve the object, the present invention has following constitution.
The method of machining a wafer for making filmed head sliders, on which a plurality of film layers are formed,
comprises the steps of: measuring curvature of a filmed surface of the wafer; selecting a machining plate having a machining face, whose curvature is in accord with that of the filmed surface of the wafer, on the basis of the result of the measuring step; and machining the filmed surface of the wafer with the selected machining plate.
Another method of machining a wafer for making filmed head sliders, on which a plurality of film layers are formed, comprises the steps of: measuring curvature of a filmed surface of the wafer; and machining the filmed surface of the wafer with a machining plate, whose curvature of a machining face is made accord with that of the filmed surface of the wafer, by external force, on the basis of the result of the measuring step.
The machining device for machining a wafer for making filmed head sliders, on which a plurality of film layers are formed, comprises: a measuring unit for measuring curvature of a filmed surface of the wafer; and a machining unit for machining the filmed surface of the wafer with a machining plate having a machining face whose curvature is in accord with that of the filmed surface of the wafer, wherein the machining plate is selected on the basis of the result measured by the measuring unit.
In the method and the device of the present invention, the filmed surface of the wafer can be precisely and uniformly machined (lapped or polished), so the wafer can be securely machined even if fine patterns are formed in an element sections, and the filmed head slider, which is capable of recording data with high density, can be easily produced. Since no load is concentrated in a part of the wafer while machining, the characteristic of the film layers are not badly influenced, and quality of the wafer for the filmed head slider can be improved.
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Gonda Kazuhisa
Sugiyama Tomokazu
Suzuki Kentaro
Fujitsu Limited
Greer Burns & Crain Ltd.
Hong William
Ostrager Allen
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