JPH0316097Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a multi-track thin film magnetic head for recording or reproducing information on a magnetic recording medium.

[Background technology]

A large number of thin film magnetic heads are formed at one time by disposing them in a matrix on a single substrate. Therefore, it is necessary to cut out each thin film magnetic head and perform grinding and polishing to form a tape sliding contact surface.
Furthermore, this grinding and polishing must be performed on the order of microns due to problems with the fine structure of the thin film magnetic head and its sensitivity.

Therefore, as shown in FIG. 1, grinding and polishing dimension indexing marks 12 are provided on both sides of a plurality of thin film magnetic head elements 10 arranged in a straight line.
A method has been devised in which grinding and polishing is performed while measuring the dimensions of the cut end surface using an optical microscope.

However, the mark 12 has a thin film thickness of 2
~4 μm, and as shown in Figures 2 and 3, the side surfaces are tapered (in the figure, a
(The dimensional difference between and b is about 5 μm), which causes a reading error in measuring the end face width. For this reason, there was a limit to the precision in forming the magnetic tape sliding contact surface.

[Purpose of invention]

The present invention takes the above facts into consideration and aims to provide a thin film magnetic head that can improve the accuracy of indexing the grinding and polishing dimensions.

[Structure of the idea]

In the thin film magnetic head according to the present invention, a plurality of thin film magnetic head elements are formed on a substrate, and the tips of the elements are arranged in a straight line. A striped grinding and polishing dimension indexing mark is provided on this substrate, and when the end surface of the substrate on the thin film magnetic head element side is cut and polished to form a tape sliding contact surface, the grinding and polishing dimension is A corresponding number of wide and narrow line end faces appear on the grinding surface.

Therefore, by counting the number of line end faces, the grinding and polishing dimensions can be easily determined, and even if the line end face has a tapered shape, this number is irrelevant, so there is no reading error. This makes it possible to improve the accuracy of indexing the grinding and polishing dimensions.

[Example of idea]

FIG. 4 shows a diagram of the principle underlying the thin film magnetic head according to the present invention. This is a cut out of one of the heads.

The substrate 16 is rectangular and has a plurality of thin film magnetic head elements 10 arranged in a straight line near its end face 18, and each element 10 corresponds to each track on the magnetic tape.

The end face 18 is ground and polished to form a tape sliding contact surface, and a magnetic tape (not shown) comes into contact with this tape sliding contact surface and runs in a direction perpendicular to the plane of the paper.

The thin film magnetic head element 10 is composed of a magnetoresistive element, and the magnitude of its reproduction output is not affected by the magnetic tape running speed, so that sufficient reproduction is possible even at low speeds. Furthermore, in order to improve the sensitivity of the thin-film magnetic head 10, the film thickness is approximately 50 nm, so that it cannot be confirmed from the end face 18 side even with an optical microscope.

On the outermost side of the plurality of thin film magnetic head elements 10,
Grinding and polishing dimension indexing marks 12 are deposited.
The mark 12 is striped and has a plurality of lines 2.
0 are formed in parallel and at regular intervals.
The direction of the line 20 is perpendicular to the proper tape sliding surface 22 (direction of arrow A in FIG. 4). The overall shape of this mark 12 is a right triangle, the hypotenuse of which intersects with the appropriate tape sliding surface 22.

As the end surface 18 of the substrate 16 is ground and polished, the end surface of the line 20 appears, and as the amount of grinding and polishing increases, the number of the line end surfaces increases, and by counting the number using an optical microscope, a fourth line 20 end surface appears. It is possible to digitally measure the grinding and polishing dimensions in the direction of arrow A in the figure on the order of microns. Also, depending on whether or not the number of line end faces of the two marks 12 is the same, it is possible to determine whether the tape sliding contact surface 22 has an appropriate inclination of the ground surface.
You can know whether it is parallel to or not.

The line end shape is trapezoidal or triangular, but
This is unrelated to the count of the number of end faces, so
There is almost no reading error, and the accuracy of indexing the grinding and polishing dimensions can be improved.

Note that the line 20 is placed on the appropriate tape sliding surface 22.
If the tape is aligned accurately with one tip end surface of the tape, it is possible to form the tape sliding surface with higher precision. Also,
Since the measurement is done digitally, the grinding and polishing process can be easily automated by using a device that automatically detects the number of line end faces using pattern recognition from a microscope image.

Next, a first embodiment of the present invention will be described with reference to FIG.

In this first embodiment, the grinding/polishing dimension indexing mark 12A is constructed by forming a narrow line 20B at the tip of a wide line 20A. however,
At the right end in FIG. 5, there is only a narrow line 20B. The lines 20A have the same width and are formed in parallel at regular intervals. The same applies to the lines 20B, and one line 20A corresponds to a certain number of lines 20B. The overall shape and arrangement of the abrasive dimension index mark 12A on the substrate 16 is the same as in FIG. 4.

Therefore, by counting the number of end faces of each of the wide line 20A and the narrow line 20B, the grinding and polishing dimensions can be determined.
Therefore, it is sufficient to count a smaller number of line end faces than in the case of FIG. Moreover, since the wide line 20A that is easy to count is included, it is possible to determine the grinding and polishing dimensions more quickly than in the case of FIG. 4, which contributes to increasing the efficiency of the grinding and polishing work.

Next, a second embodiment of the present invention will be described with reference to FIG.

This second embodiment is similar to the first embodiment in that the grinding and polishing dimension indexing mark 12C is composed of a wide line 20A and a narrow line 20B, but a mark 20X for low precision and a mark 20X for medium precision are used. This embodiment differs from the first embodiment in that it is divided into a precision mark 20Y and a high precision mark 20Z.

Therefore, it is possible to determine the grinding and polishing dimensions with an accuracy that corresponds to the required accuracy.

Note that the end side of the narrow line 20B may be parallel to the appropriate tape sliding surface.

Grinding and polishing indexing marks can generally be formed during the manufacturing process of thin film magnetic head elements. For example, it can be formed in the same layer as the magnetic shield layer formed on the upper layer of the magnetoresistive element and made of the same material as the magnetic shield material.

[Effect of idea]

Since the thin film magnetic head according to the present invention has a striped grinding and polishing dimension indexing mark having wide and narrow lines, the grinding and polishing dimensions can be determined by counting the number of line-grinded and polished end faces. This has an excellent effect in that it is possible to improve the indexing accuracy of the grinding and polishing dimensions without being affected by the shape of the end face.

[Brief explanation of drawings]

Fig. 1 is a front view showing a conventional example, Fig. 2 is a partially enlarged view of Fig. 1, Fig. 3 is a plan view of Fig. 2, and Fig. 4 is a diagram showing the principle underlying the present invention. FIG. 5 is a partial front view showing the first embodiment of the present invention, and FIG. 6 is a partial front view showing the second embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Thin film magnetic head element, 12... Grinding and polishing dimension index mark, 14... Thin film magnetic head, 16... Substrate, 20, 20A, 20B, 20C... Line, 2
2... Tape sliding contact surface.

Claims (1)

[Scope of utility model registration request] In a thin film magnetic head in which a plurality of thin film magnetic head elements are formed on a substrate with their tips aligned in a straight line, a number of line end faces corresponding to the grinding and polishing dimensions of the end face of the substrate on the thin film magnetic head element side are ground and polished to the end face. 1. A thin film magnetic head having a striped abrasive dimension indexing mark arranged to appear, the mark consisting of a plurality of wide lines having a narrow line at the tip.