JP2000268324A - Manufacture of magnetoresistance effect-head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grind a wafer with high accuracy and to enhance the production yield of a high-performance magnetoresistance effect element. SOLUTION: In this manufacturing method for a magnetoresistance effect head, respective layers which comprise a magnetoresistance effect film and a terminal part constituting the magnetoresistance effect-head are formed on a wafer 10, the whole face on the film formation face of the wafer 10 is then covered with a protective film, the protective film is ground and machined by a rotary whetstone 20 comprising a ring-shaped whetstone part 22, the end face of the terminal part is exposed, the end face of the terminal part and the surface of the protective film are formed to be flat faces, and the magnetoresistance effect head is formed. The grinding operation uses the whetstone 20 in which many grooves crossing the whetstone part 22 in the transverse direction are formed is used on a face on which a product to be worked, by the whetstone part 22 is ground.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetoresistive head used for recording and reproducing information in a magnetic disk drive, and more particularly, to grinding in a wafer process for forming a magnetoresistive head. It relates to a processing method.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and large-capacity of magnetic disk drives, magneto-resistive heads whose output does not depend on the peripheral speed and whose output is high can be obtained as a magnetic head used for recording and reproducing information. Is attracting attention. In manufacturing this magnetoresistive head, a large number of elements are obtained by patterning a magnetoresistive film or a required insulating film on the surface of a ceramic wafer as a base material. In the wafer process of forming the magnetoresistive film, etc., after forming the magnetoresistive film, terminals, coils, etc., the entire surface of the wafer is covered with a protective film such as alumina, and the protective film is ground and the surface is mirror-finished. Grinding is performed.

The thickness of a protective film made of alumina or the like is about 60 μm, and the thickness of the thickest terminal portion under the protective film is about 50 μm. The process of grinding the protective film in the grinding step is to expose the end face of the terminal portion and to process the end face of the terminal portion and the surface of the protective film into a flat mirror surface. Usually, since the terminal portion is formed by depositing copper, the protective film such as alumina is ground in the protective film grinding step, and the grinding is stopped when the terminal portion is exposed.
In this grinding step, a grinding device using a general rotating grindstone is used.

[0004]

The grindstone used in the above-mentioned grinding process in the wafer process has a grindstone portion in contact with the surface of the work in a cylindrical shape having a diameter of about 200 mm. A diamond cup wheel using diamond is used. However, in this conventional whetstone, since the surface of the whetstone is in close contact with the surface of the work at the time of grinding, the amount of the grinding fluid passing between the whetstone surface and the work surface is limited, and the desired surface accuracy is reduced. There was a problem that it could not be obtained.

In order to perform a grinding process, particularly a mirror surface grinding process for maximizing the surface roughness of the work surface, a grinding fluid (a water-soluble cutting fluid) is applied between the surface of the grindstone and the surface of the work to be processed. (A solution diluted with water) must be supplied efficiently. In the conventional diamond cup wheel, since the surface of the grindstone is simply formed as a flat surface, the grinding fluid is not efficiently supplied, and a desired surface accuracy cannot be obtained. The present invention has been made to solve these conventional problems. By improving the shape of a grindstone used in a wafer grinding process, it is possible to perform extremely high-precision mirror surface grinding and achieve high performance. It is an object of the present invention to provide a method of manufacturing a magnetoresistive element capable of manufacturing a magnetoresistive element with high yield.

[0006]

The present invention has the following arrangement to achieve the above object. That is, after forming each layer including the magnetoresistive effect film and the terminal portion constituting the magnetoresistive head on the wafer, the entire surface of the film formation surface of the wafer is covered with a protective film, and the protective film is formed in a ring shape. Grinding using a rotary grindstone having a grindstone portion to expose the end surface of the terminal portion, and forming the end surface of the terminal portion and the surface of the protective film on a flat surface to form a magnetoresistive head. In the method of manufacturing a magnetoresistive head, during the grinding, using a grindstone provided with a large number of circumferentially provided grooves crossing the grindstone portion in a width direction on a surface of the grindstone portion on which a workpiece is ground. Features. In addition, the use of a grindstone having a groove formed so that the outer peripheral side is wider than the inner peripheral side of the grindstone portion has an advantage that the flow of the grinding fluid from the inside to the outside of the grindstone portion is improved. is there. In addition, grinding with a grindstone provided with a groove inclined in the tangential direction with respect to the radial direction of the grindstone portion, with the outer peripheral side facing the rotation direction of the grindstone with respect to the radial direction of the grindstone portion, is not a grinding stone. This is effective in improving the flow of the grinding fluid in and out of the portion.

[0007]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of a grinding apparatus for grinding a film-formed wafer 10 as a workpiece in a method of manufacturing a magnetoresistive head. The wafer 10 is corrected by a vacuum chuck 12 so that the film-forming surface faces outward and becomes a flat surface, is vacuum-sucked, and is rotated around the center line together with the vacuum chuck 12 in the vacuum-sucked state. On the other hand, the grindstone 20 is set above the wafer 10 with the grindstone portion 22 facing the processing surface (film formation surface) of the wafer 10.

The grindstone 20 has a ring-shaped (cylindrical) grindstone portion 22 attached to a metal circular base plate 24, and is attached to a rotating mechanism that rotates the grindstone 20 at high speed around a center line. . As shown in FIG. 1, the rotating surface of the grindstone 20 is made parallel to the surface of the
0 while rotating the wafer 1 while supplying the grinding fluid 30.
Grinding is performed by bringing the grindstone 20 into contact with the surface of No. 0. 32 is a nozzle for supplying a grinding fluid. In the embodiment, the wafer 10 and the grindstone 20 are arranged so that their center positions are deviated.

The wafer 10 to be processed is formed by forming a required magnetoresistive film, forming terminals and coils, etc., and forming alumina as a protective film on the entire surface of the film forming surface of the wafer 10. It was done. In this grinding process,
The film forming surface of the wafer 10 is mirror-polished with a grindstone 20 to expose the copper terminal portion, and the protective film of alumina and the exposed surface of the terminal portion are ground to a flat mirror surface.

The feature of the grinding process according to the present embodiment lies in the configuration of the grindstone 20 for grinding the wafer 10. A groove is formed on the surface of the grindstone portion 22 that is pressed against the workpiece to form the grinding fluid 30. The point is that supply and distribution are performed efficiently. FIG. 2 shows a plan view of the grindstone 20. The grindstone 20 is obtained by attaching a grindstone portion 22 in a ring shape to a base plate 24 formed in a disk shape using a metal plate. The base plate 24 used in the present embodiment has an outer diameter of 200 mm. The outer diameter of the grindstone portion 22 is set slightly smaller than that of the base plate 24, and is formed to have a width of 3 mm.

The grinding wheel portion 22 is formed by kneading a diamond for grinding as a grinding material into a fixing material. In the present embodiment, the ring-shaped grindstone portion 22 is provided with a large number of grooves 22a crossing the grindstone portion 22 in the width direction at predetermined intervals in the circumferential direction. The groove 22a is partially provided). The groove 22a provided in the grindstone portion 22 in the present embodiment is provided so that its outer peripheral side is directed in the rotation direction of the grindstone 20 and is inclined at about 45 ° tangential to the radial direction of the grindstone portion 22 with respect to the arc. The reason why the direction of the groove 22a is inclined from the radial direction is to make it easier for the grinding fluid 30 to flow inside and outside the grindstone portion 22. When the grindstone 20 rotates in the direction of the arrow in the figure, if the groove 22a is inclined as shown in the figure, the rotation of the grindstone 20 makes it easier for the grinding fluid 30 to enter the groove 22a. Becomes easier to move.

As shown in FIG. 2, the arrangement in which the grooves 22a are inclined is not limited to the case where the grinding fluid 30 is supplied from the inside of the grindstone portion 22 and the grinding fluid is supplied from the outside of the grindstone portion 22 as shown in FIG. Even in the case where the grinding liquid 30 is supplied and the grinding is performed, there is an operational effect that the grinding fluid 30 can easily flow through the grinding stone portion 22. Making the grinding fluid 30 flow easily inside and outside the grindstone portion 22 enables efficient and reliable grinding and reliably improves the surface accuracy.

FIG. 3 shows another example in which a groove is provided in the grindstone portion 22. The grindstone 20 of this embodiment is characterized in that the grooves 22b are arranged in the radial direction of the arc of the grindstone portion 22, and the shape of the grooves 22b is formed wider on the outer peripheral side than on the inner peripheral side. In the embodiment, the shape of the groove 22b is 2 mm on the inner peripheral side and 3 mm on the outer peripheral side.
mm width. The reason why the shape of the groove 22b is made narrower on the inner peripheral side and wider on the outer peripheral side is that when the grinding liquid 30 is supplied to the inside of the grindstone portion 22 to perform the grinding, the grindstone portion 22 is formed.
This is to make it easier for the grinding fluid 30 to flow from the inside to the outside.

To facilitate the flow of the grinding fluid 30 through the grindstone portion 22 when the grindstone 20 is rotated,
Accordingly, there is a great effect that the grinding fluid 30 is prevented from staying in a portion where the workpiece is being ground, and the ground material is easily discharged together with the grinding fluid, thereby enabling efficient and reliable grinding. Further, since the grinding fluid 30 is easily passed, new grinding fluid 30 is supplied to the grinding portion one after another, and reliable grinding is performed, so that the surface accuracy of the ground surface can be effectively improved. .

The grindstone portion 22 decreases with use, but if the grooves 22a and 22b remain, an effective operation and effect can be obtained. The shape, size, depth and the like of the grooves 22a and 22b can be appropriately selected depending on the size and width of the grindstone portion 22, the size and material of the workpiece, and are limited to the size, shape and the like of the above embodiment. Not something.

The above-mentioned grinding method is suitable for use in a device requiring extremely high precision processing, such as a magnetoresistive element. In particular, since the wafer used for the manufacture of the magnetoresistive element has a complicated uneven shape on the underlayer, it may be affected by the uneven surface of the underlayer when grinding with alumina as a protective film. It is important that grinding can be performed without any problems. Usually, after this grinding process, a polishing process is performed as a finishing process. In the polishing process, the surface accuracy at the time of the grinding process is affected by the finishing accuracy and also by the unevenness of the base. Therefore, it is extremely important to perform a high degree of surface precision by grinding. In this regard, the grinding using the grindstone 20 of the above embodiment has a good grinding surface accuracy, and in some cases eliminates the need for finishing polishing, thereby improving grinding and polishing efficiency, and providing a highly reliable magnetoresistance. It is possible to obtain an effect element.

[0017]

According to the method of manufacturing a magnetoresistive element according to the present invention, as described above, it is possible to reliably and efficiently grind a wafer having a magnetoresistive film covered with a protective film. This makes it possible to improve the production yield of the magnetoresistive element, and to manufacture a highly reliable product that can respond to high performance of the magnetoresistive element.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a method of grinding a wafer using a grindstone.

FIG. 2 is a plan view showing an example of a grindstone used for grinding.

FIG. 3 is a plan view showing another example of a grindstone used for grinding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Wafer 12 Vacuum chuck 20 Grindstone 22 Grindstone part 22a, 22b Groove 24 Base plate 30 Grinding liquid 32 Nozzle

Claims (3)

[Claims] After forming a layer including a magnetoresistive film and a terminal portion constituting a magnetoresistive head on a wafer, a whole surface of a film forming surface of the wafer is covered with a protective film. Grinding using a rotary grindstone having a ring-shaped grindstone portion to expose the end surface of the terminal portion, and forming the end surface of the terminal portion and the surface of the protective film on a flat surface to form a magnetoresistive head In the method of manufacturing a magnetoresistive head, a grindstone provided with a plurality of circumferentially provided grooves crossing the grindstone portion in a width direction on a surface of the grindstone portion on which a workpiece is ground is used in the grinding process. A method of manufacturing a magnetoresistive head. 2. The method for manufacturing a magnetoresistive head according to claim 1, wherein a grindstone having a groove formed on the outer peripheral side wider than the inner peripheral side of the grindstone portion is used. 3. Grinding using a grindstone provided with a groove inclined in a tangential direction with respect to the radial direction of the grindstone portion, with the outer peripheral side facing the rotation direction of the grindstone with respect to the radial direction of the grindstone portion. The method for manufacturing a magnetoresistive head according to claim 1, wherein: