JPH0416842B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic head with high reproduction efficiency.

Usually, a magnetic head core is constructed by a pair of core halves abutted against each other, and each core half is arranged to face each other with a non-magnetic material interposed therebetween. For example, as shown in FIG.
and 2 are arranged substantially parallel to each other with a predetermined distance (distance corresponding to gap length 3) between them. This means that there is also a magnetic gap between the back gap forming surfaces of each core half 1 and 2, which corresponds to the distance between the front gap forming surfaces, that is, the gap length 3. During playback, the magnetic resistance created by this magnetic gap causes playback. known to reduce efficiency. In order to prevent this reduction in regeneration efficiency,
As shown in FIG. 2, a step 4 corresponding to the above-mentioned gap length 3 is provided between at least one of the core halves (e.g. 2) between the operating gap forming surface and the back gap forming surface, and the core half on the back gap side is It has been proposed to meet the surfaces so that they are substantially flush. However, forming this step by machining is difficult because it is difficult to control the step and to ensure the flatness of the machined surface. Therefore, a method of producing the machined surface to obtain this step using a chemical etching method has been tried.If the magnetic head core material is ferrite, it is often etched with concentrated phosphoric acid. However, it has the disadvantage that the etching rate is unstable, leading to variations in the etching amount, and it is difficult to achieve the required accuracy of the working gap within ±5%.

The present invention has been made in view of such drawbacks, and the working gap forming surface formed to have a step with respect to the back gap forming surface of the magnetic head core is replaced by a core having a surface substantially flush with the back gap forming surface. The object of the present invention is to provide a method for manufacturing a magnetic head, which is obtained by mechanochemically polishing the portion of the material where the working gap forming surface is to be formed, and then applying an ion beam.

Etching using an ion beam (ion beam milling) is characterized by the fact that the etching is done by the physical action of the etching gas, and because the ion beam chamber and processing chamber are separated, the degree of vacuum in the processing chamber can be increased. Therefore, the reproducibility of the etching rate is said to be extremely good (within ±5%). Therefore, if this ion beam milling is used to form a step between the back gap forming surface and the working gap forming surface of the magnetic head core, it is advantageous because the control of the step can be made relatively simple. Therefore, it can be said that it is suitable for forming the working gap forming surface. However, even if the surface of the core material before beam processing is polished to a mirror surface, the surface condition is not homogeneous (for example, even if it looks like a flat mirror surface at first glance, it actually looks like a flat mirror surface). ), and in this case, even if the ion beam processing is performed, the etching speed will differ locally, so that the surface condition after etching may be even worse than the initial condition. In order to prevent this, it is necessary to remove the process-affected layer that may occur during mirror polishing from the surface to be processed, and to ensure that the surface has sufficient flatness and surface roughness before performing this beam processing. Therefore, in the present invention, the workpiece surface polished to a mirror surface (at least the portion corresponding to the working gap forming surface of the core material having a surface substantially flush with the back gap forming surface, that is, the portion to be subjected to ion beam processing), ), the workpiece is subjected to mechanochemical polishing, which applies mechanical energy to the workpiece and actively utilizes the induced chemical reaction for polishing, to improve the homogeneity of the polished surface, followed by the ion beam milling described above. By doing so, the step can be formed with a high yield while ensuring the surface accuracy of the working gap forming surface.

Next, examples of the method of the present invention will be briefly described.
FIG. 3 shows an outline of the processing steps of the method of the present invention, in which 5 is a wafer made of a magnetic material, such as a single crystal ferrite material, and the surface of the wafer, which will become the abutting surface, is polished to a mirror finish by the conventional method. ing. Microscopically, the process-affected layer 6 is formed on this processed surface as described above (FIG. 3A). Regarding this wafer 5,
Mechanochemical polishing is performed to remove the process-affected layer 6, resulting in a good finished surface 5a with a shallow process-affected layer.
(Figure 3 B). Then, as usual,
The winding groove 7 is formed, and a track width defining groove (not shown) extending in a direction perpendicular to the winding groove is formed (FIG. 3C). Next, patterning is performed by ordinary photolithography except for the surface to be subjected to ion beam milling to form a protective film 8 (FIG. 3D). Next, if this sample is placed in a 10'' micro-etch system and processed under the following conditions, the processed surface 5b can be etched by 0.37 μm.
An operating gap forming surface 5c having a step 4 relative to the back gap forming surface can be formed.
Energy (v/mA) 500/440 Current density (μA/cm ² ) 600, Angle (θ) 30, Time (min) 20,
Argon pressure (Torr) 2.0×10 ^-4 , arc (V/
A) 60/60, cathode (V/A) 11/39, coil (V/A) 19/0.45, suppressor (V/mA)
300/40, Neutra (V/A) 50/10.5. still,
This ion beam milling may be performed before the groove machining shown in FIG. 3C. FIG. 3E shows a state in which the protective film 8 has been removed. Next, the wafer 5A that has been subjected to ion beam milling and the wafer 5B shown in FIG. The gap forming surfaces are opposed to each other with a space corresponding to the step 4 above. Thereafter, the space is filled with glass 9, and each wafer is integrated with a bonding material (not shown) (FIG. 3). This integration can be achieved by filling the track width defining groove and the lower end of the back gap forming surface with a bonding material. Next, the integrated block is subjected to molding of the tape contacting surface, slicing, and thickness processing of the core in the conventional manner to obtain a head chip. and,
This head chip is attached to a head base and a coil is wound to produce a magnetic head. Instead of glass infiltration into the space, a suitable spacer material may be attached to eliminate the level difference. Further, in order to form a predetermined gap length when each wafer is butted, ion beam processing may be performed on a wafer other than the wafer having the winding groove, or on each wafer to be butted. .

In the magnetic head according to the method of the present invention, the back gap forming surfaces of the abutting core halves are in direct contact with each other, so the magnetic resistance at this abutting portion can be significantly lowered, and a decline in the regenerative efficiency of the magnetic head can be prevented. can. In addition, the working gap forming surface, which has a step difference with respect to the back gap forming surface, is etched by the ion beam milling method, which improves the surface precision, which leads to improved manufacturing yield and lower cost of magnetic heads. I can contribute.

[Brief explanation of drawings]

Figure 1 is a typical configuration diagram of a conventional magnetic head.
FIG. 2 is a block diagram of a conventional magnetic head that contributes to improving reproduction efficiency, and FIGS. 3A to 3F are diagrams showing the manufacturing process of the magnetic head including the method of the present invention. Explanation of main drawing numbers, 5A, 5B... wafers forming one set of core halves, 4... step.

Claims (1)

[Claims] 1. A magnetic head core formed by a pair of core halves abutted against each other, wherein the working gap forming surface of at least one core half is configured to have a step with respect to the back gap forming surface of the one core half. In the method for manufacturing a magnetic head, the surface of the wafer serving as the one core half is polished to a mirror surface, and then the process-affected layer formed by the polishing is removed by mechanochemical polishing. A method of manufacturing a magnetic head, characterized in that the step is formed by applying an ion beam to a portion where a working gap forming surface is to be formed.