JPH03142703A - Method and device for manufacturing thin film magnetic head - Google Patents

Abstract

PURPOSE:To execute the finish work of a submicron order for the gap depth of a magnetic head by measuring the dimension of a marker by a photodetecting means, feeding track the measured result to a relative positioning means and executing grinding and finishing. CONSTITUTION:In the thin film element part of each head chip, a marker 25 for gap depth detection to appear on a working surface with the work is provided in advance and the dimension of the marker 25 is measured by a photodetecting means 20. The measured result is fed back to a relative positioning means 21, which can control a relative position to an object 11 to be worked with high accuracy, and the grinding is executed by a rotary grindstone 15 based on feedback data. Further, the finishing is executed by a grinding tape 18 for finish. Thus, the accuracy for the gap depth of the thin film magnetic head can be controlled with high working efficiency by the submicron order.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for manufacturing a thin film magnetic head, and in particular, to a thin film magnetic head that can finish the gap depth of a magnetic head with high precision. The present invention relates to a head manufacturing method and manufacturing apparatus.

[Conventional technology]

As shown in FIG. 3, the thin film magnetic head has a substrate 1 with
A lower magnetic body 3, an upper magnetic body 5, an insulator 4, and a conductor coil 6 are patterned through an insulator 2, and a minute gap of 5 to 2 μm is provided between the magnetic bodies 3 and 5, and the upper gap is , by machining the gap side to obtain a predetermined gap depth d.

Since this gap depth d greatly affects the performance of the magnetic head, particularly strict dimensional tolerances are required for thin film heads, and tolerances of 1 μm or less are required. Therefore, it is necessary to measure the gap depth d when processing the upper gap side, but since the magnetic core is covered with the protective film 7, accurate measurement is difficult.

To deal with this, many methods have been proposed to date in which a thin film is formed as a detection marker indicating the gap depth d. There is a method in which an electrical resistance sensing element is formed and the gap depth d is determined by utilizing changes in the electrical resistance value of the element during processing. However, in this case, there is a problem that the direct correspondence between the electrical resistance value and the gap depth d is difficult.

A method of detecting the gap depth by optically measuring the dimension t of a gap depth detection marker appearing on the machined surface has also been proposed (for example, Japanese Patent Laid-Open No. 54
-58426 publication).

In this method, as shown in FIGS. 4 and 5, a marker 8 is formed on both sides of the magnetic core by combining two identical right-angled triangular figures 9 and 10 in opposite directions, and then processed. This method determines the gap depth d by optically measuring the dimensions X and X, which change as the gap progresses. In this case, the line widths at the center of the figures 9 and 10 are the same size, and this is set as the marker reference position B, and the reference position B is formed so as to coincide with the eartub depth reference position Majin. As a result, the gap depth d can be determined by measuring υ, xl, and xb. In this case, in order to keep the tolerance of the gap depth d within the submicron range, it is necessary to set the dimension reading accuracy of the above marker to around (L1 μm). Therefore, in the example described in the above-mentioned publication, lapping is also mentioned. However, when lapping is performed, even if the gap depth can be measured with high accuracy, dimensional control is necessary. However, even if the machining time is controlled, it is difficult to obtain high machining accuracy due to large errors.

Therefore, in order to improve the machining accuracy, it is necessary to increase the frequency of measurement, and the machining takes a lot of time.

- Although grinding has a processing dimension control function, the surface roughness of the resulting machined surface is not as good as in lapping, so the marker reading accuracy decreases.
It is difficult to obtain a reading accuracy of around μm.

[Problem to be solved by the invention]

As mentioned above, in the conventional technology, when trying to control the dimensional accuracy of the gap depth in the sub-micron range, lapping has poor processing efficiency, and grinding has poor marker reading accuracy. The purpose of the present invention is to solve the above-mentioned problems of the conventional technology, to achieve high machining efficiency, and to form gaps with submicron accuracy. An object of the present invention is to provide a method and apparatus for manufacturing a thin film magnetic head that can control the depth.

[Means to solve the problem]

The above purpose is to improve the dimensions of the gap depth detection marker that appears on the machined surface due to the processing provided in advance on the thin film element portion of each head chip when processing a head block tape running surface that has a large number of thin film elements. An optical detection means that can perform measurement, a relative positioning means that can control relative positioning with the workpiece with high precision by feedback of the measurement results, and a rotation that performs grinding based on the positioning results. Using a manufacturing device equipped with a grindstone and a processing means consisting of a finishing abrasive tape, various gap depth detection markers are previously provided on the thin film element portion of each head chip on the processed surface during processing. j? Then, the dimensions of the marker are measured by an optical detection means, the measurement results are fed back to a relative positioning means that can control relative positioning with the workpiece with high precision, and based on the feedback data, This can be achieved by cutting with a rotary grindstone and finishing with a finishing abrasive tape.

[Effect]

With the above configuration, the surface to be machined is first ground with a rotary grindstone and then finished with a finishing abrasive tape, so that the roughness of the machined surface of the workpiece can be adjusted to the maximum height (R
max ) (1027111 or less. As a result, the dimensions of the gap depth detection marker formed on the machined surface can be measured by optical detection means by % a1
It is possible to read with an accuracy of around μm. Based on this feedback signal, it is possible to determine the amount of grinding by the grinding wheel at I11 μm, so the accuracy of the gap depth can be improved. It can be controlled on the submicron order.

Moreover, since the workpiece can be installed and fixed in the processing machine, and then the work can be carried out continuously without having to remove the workpiece from the housing after processing, there is no error caused by attaching and removing the workpiece. This makes it possible to ensure gap depth with submicron accuracy.

〔Example〕

Hereinafter, the manufacturing method and manufacturing apparatus of the present invention will be specifically explained with reference to Examples.

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of a manufacturing apparatus according to the present invention, in which vibration isolating device 23t is placed on paste 22,
A table 14 is equipped with a motor 15 that holds the workpiece 11 and gives it a swinging motion, a fine movement mechanism 12 that adjusts the inclination of the workpiece 11 in the longitudinal direction, and a table 14 that gives reciprocating motion to the whole. A grinding wheel processing section includes a movable table 17 equipped with a motor 16 that gives rotational motion to the grinding wheel 15, and a movable table 17 that gives the grinding wheel 15 the amount of cut into the workpiece 11, and a grinding wheel processing section that moves the abrasive tape 18 in one direction. Abrasive tape processing section 1 that performs finishing processing on the workpiece 11
9 and an optical detection means 20 for optically reading a gap depth detection marker buried in the processing surface of the workpiece 11 in advance, and further comprising a control rack [21]. shows.

As shown in FIG. 2, the workpiece 11 has a large number (for example, 30) of magnetic cores 24 formed on a substrate.
Note that gear lub depth detection markers 25 are formed at both ends of each magnetic core 240. Here, by forming the marker 25 in the shape of, for example, a right-angled isosceles triangle and measuring the width of the marker 25 from the machined surface, the gap depth can be determined using a 1=1 correspondence relationship. can. ! !
In addition, the dimensions of the workpiece 11 are approximately 52 mm in length and 41 mm in length.
1. Approximately 30 magnetic cores 24 are formed with a height of 2 mm and a pitch of approximately 1 mm in the 32 mm direction, and a cylindrical surface with a radius of curvature of 10R is formed on the surface of this workpiece 11 with a width of 1 mm and a length of 32 mm. , Moreover, the gap depth of each magnetic core 24 is set to 1.
This is intended to control the thickness to 5 μm.

The processing procedure is as follows. That is, the workpiece 11 is held without a groove, and the motor 15 applies a swinging motion with a radius of curvature IQR (for example, swinging rotation speed of about 12° rpm).
The gap depth detection marker 24 of the workpiece 11 appears on the machined surface by the grinding wheel 15! Perform grinding with 0
For example, when the detection marker 24 is formed with a position groove of 60 μm from the position of the gap depth 0, the grinding process is performed to approximately the depth of the ear tip 4071A. In this case, the accuracy of the gap depth is influenced by the pre-machining accuracy of the workpiece 11, the accuracy of the installation to the processing machine, the machining accuracy of the grinding wheel 15, etc., but it can be easily machined to about ±10 μm, and as described above. It is possible to drop markers 24 on the work surface. For example, the grinding wheel 15 has a diameter of 100 mm.
Processing is performed using a resin-bonded diamond grindstone with a cup-shaped abrasive grain size of ◆5000 mm and rotated at 80 Q Orpm.During the grinding process, the workpiece 11 is placed on the table 1.
4 stroke approximately 40 mm, speed approximately 60 ml
Reciprocate with lI/rn in. by this,
The machined surface of the workpiece 11 has a surface roughness (LD5~a1μmR)
It is possible to finish up to about max. However, with this level of surface roughness, the dimensions of the marker 240 are approximately α1j1! I
It is difficult to measure with an accuracy of I.

Next, the workpiece 11 is moved by the table 14,
The polishing tape processing unit 19 performs finishing processing on the cylindrical surface of the workpiece 11 . In this case, a chromium oxide tape with an abrasive grain diameter of 5 μm is used as the abrasive tape 18, and is moved in one direction at a speed of about 10 mm/min while the workpiece 11 is being moved in an oscillating motion. It is pressed against the cylindrical surface with a predetermined pressure and polished at a constant pressure. In this case, the machining amount is approximately 1 minute (L2μm), and the machining amount error can be easily suppressed to ±a1μm or less.As a result, the surface roughness of the machined surface is approximately (LO2μm Ra + a
It can be finished to x or less.

Next, the workpiece 11 is moved to the position of the optical detection means 20 by the table 14, and the marker 2 formed on the processing surface is
Read the dimensions of 4. In this case, the surface roughness of the machined surface is (L
Since O2μm is less than Rmax, the dimension reading accuracy of the macaque 24 can be approximately 1 μm. This detection means 20 reads the gap depth of both fractional cores of the workpiece 11 having a length of 32 mm, and this read value is sent to the control device 2.
1, calculate the amount of horizontal inclination of the workpiece 11 and the machining amount of remaining υ, correct the horizontal inclination of the workpiece 11 using the minute movement mechanism 12, and adjust the positioning accuracy of the grinding wheel processing section. The remaining machining amount is given by the moving table 17 having α1 μm. After performing the grinding process in this manner, the polishing process is performed again using the abrasive tape 18 and measurement is performed using the optical detection means 20, and the gap depth of the workpiece 11 is determined to be 15±.
(Repeat the same operation with 1 which becomes L5-m.

In this case, 5 μm may be input into the control device in advance as the allowable value for the left and right gap depths m of the workpiece 11.

By applying the above processing apparatus and processing procedure, the target gap depth of 15±a5 μm could be obtained in about three processing steps. Moreover, the processing time is approximately 10
This was a significant reduction in processing time compared to conventional lapping processing.

〔Effect of the invention〕

As described above, by applying the manufacturing method and manufacturing apparatus of the present invention to the processing of a head block tape running surface having a large number of thin film elements, it is possible to perform grinding processing that allows positioning to be controlled at a submicron level. Since the finishing process using the abrasive tape can be performed continuously on the same processing machine, it is possible to easily achieve a machined surface roughness of less than (LO2μm Rmax). Furthermore, the gap depth can be detected by optical detection means. The size of the marker for 01
A manufacturing method and manufacturing method for a thin film magnetic head that can measure with μm accuracy, solves the problems of conventional technology, and can obtain the gap depth of a magnetic head with high accuracy and high efficiency. We were able to provide the equipment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of an embodiment of the manufacturing apparatus of the present invention, FIG. 2 is a front view showing a workpiece processed by the manufacturing method and manufacturing apparatus of the present invention, and FIG. 3 is a view of a thin-film magnetic head. FIGS. 4 and 5 are a partial cross-sectional view showing the structure, and are a front view of a workpiece and a principle diagram for explaining the processing procedure by the conventional manufacturing method. 1...Substrate, 2...Insulator, 3...
... lower magnetic material, 4 ... insulator, 5 ...
...Top magnetic body, 6...Conductor coil, 7...
... Wt retention film, 8... Marker, 9.10...
...Figure (right triangle), 11...Workpiece, 12...Minute movement mechanism, 13...
Ichigo-ta, 14...Chee7'le, 15...
・Grinding wheel, 16...Motor, 17...
・Moving table, 18... Abrasive tape, 19.
...Abrasive tape processing section, 20...Optical detection means, 21...Control device, 22...
・Pace, 23... Vibration isolator, 24...
・Magnetic core, 25・i...Gap depth detection marker. Ivy 10 Ivy 50 Fig. 4 Fig. 50

Claims (1)

[Scope of Claims] 1. In processing a head block tape running surface having a large number of thin film elements, a marker for detecting the gap depth that appears on the processing surface during processing is attached to the thin film element portion of each head chip. The dimensions of the marker are measured in advance by an optical detection means, the measurement results are fed back to a relative positioning means that can control the relative positioning with the workpiece with high precision, and the dimensions of the marker are measured based on the feedback data. A method for manufacturing a thin film magnetic head, which comprises grinding with a rotating grindstone and finishing with a finishing abrasive tape. 2. In a head block tape running surface processing device having a large number of thin film elements, measure the dimensions of the gap depth detection marker that appears on the processed surface due to the processing previously provided on the thin film element portion of each head chip. a relative positioning means that can control relative positioning with a workpiece with high precision by feedback of the measurement results, and a rotary grindstone that performs grinding based on the positioning results. and processing means consisting of a finishing abrasive tape.