JPS6226618A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To permit easy and accurate grooving by forming a marker film for assuring the depth accuracy of grooving on a lower magnetic material. CONSTITUTION:The 1st insulating layer 2 consisting of SiO2, etc. is formed on one plane of the lower magnetic material 1 except the front gap part and back gap part thereof. The 1st coil conductors 3 consisting of a metallic Cu or Al conductor are formed by spiral pattern etching at prescribed intervals on the 1st insulating layer 2. The conductors 3 are etched by a photolithographic technique in such a manner that the marker film 4 having the width within the permissible error of the groove depth remains in the patterning etching of the conductors. The working accuracy for grooving to control the width of the opposite contact with a magnetic recording medium is remarkably improved by providing the marker film 4.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is based on PCM (Pulse Code Mod
The present invention relates to a thin film magnetic head used in a recording/reproducing device and the like, and particularly to a marker film for checking the depth of a groove in a groove processing process.

[Summary of the invention]

According to the present invention, when confirming the depth of the groove in the groove processing process of a thin film magnetic head, a marker film is formed on the lower magnetic body to ensure the depth accuracy of the groove processing. The purpose is to perform groove machining with high precision.

[Conventional technology]

In general, in thin-film magnetic heads, the lower magnetic material, coil conductor, upper magnetic material, etc. that make up the head are formed by vacuum thin film forming technology such as sputtering, which makes it easy to mass produce and provides heads with uniform characteristics. In addition, since patterning is performed using photolithography technology, miniaturization of narrow trunks, narrow gaps, etc. is easy.

Therefore, in the thin-film magnetic head, the head magnetic field involved in recording becomes steep, making it possible to perform high-density recording, high-resolution recording, and further miniaturization.

This type of thin-film magnetic head requires a narrow width of contact with the magnetic recording medium to ensure contact with the magnetic recording medium, so grooves are formed near the surface facing the magnetic recording medium to The width of contact with the recording medium is regulated.

Further, in the thin film magnetic head, it is difficult to increase the number of turns of the coil conductor due to its structure. Therefore, in the magnetic path forming part, the formation of the coil conductor is concentrated into a minute space to reduce the depth length and increase the recording efficiency of the head, and in other parts, the coil conductor is formed in a focused manner to improve the electrical characteristics of the coil conductor. It is formed over a fairly wide space. Therefore, the coil conductor is formed so as to extend to the vicinity of the groove.

However, if the grooves are formed too deep, the coil conductor will also be cut, and if the grooves are too shallow, the magnetic recording medium will be scratched by waviness or the like. Therefore, the permissible error range for this groove depth must be set to an extremely small value of ±5 μm to ±10 μm.

Therefore, in this type of thin 119 magnetic head, it is an important issue to process the grooves so that the grooves have a predetermined depth in the groove processing step.

Conventionally, after cutting the groove, the head is removed from the processing machine and the depth is checked using a microscope. However, with this method, the head that has been removed must be set back into the processing machine to machine the grooves, and therefore there is a problem in that setting errors are likely to occur.

Alternatively, there is a method of forming a dummy with a predetermined groove depth in advance and checking the groove depth by comparing it with this dummy, but in this case, extra labor is required to create the dummy. The disadvantage is that it requires

[Problem that the invention seeks to solve]

As described above, in the conventional thin film magnetic head, when attempting to check the depth of the groove during groove machining, it is very time consuming and there is a problem in that accurate confirmation cannot be achieved.

Therefore, the present invention has been proposed in view of the above-mentioned circumstances, and an object of the present invention is to propose a thin-film magnetic head in which the above-mentioned groove processing can be easily and accurately performed.

[Means for solving problems]

In order to achieve this object, the thin film magnetic head of the present invention has a coil conductor and an upper magnetic body laminated on a substrate with an insulating layer interposed therebetween, and grooves are formed to regulate the contact width with the magnetic recording medium. The thin film magnetic nodule formed by the above method is characterized in that a marker film is formed on the lower magnetic body to ensure the depth accuracy of the groove processing.

[Effect]

In this way, by forming a marker film (having a width within the tolerance of the above-mentioned groove processing method) to ensure the depth accuracy of groove processing on the lower magnetic material, the groove processing can be performed using the marker film. By simply checking that the depth a is within the allowable error range, it is possible to confirm that the depth a is within the allowable error.

〔Example〕

An embodiment of a thin film magnetic head to which the present invention is applied will be described below with reference to the drawings.

In the thin film magnetic head of the present invention, as shown in FIG. 1(A) and FIG. 1(B), there is no front gap portion G or bank gap portion G' on one plane of the lower magnetic body (1). A first insulator N(2) made of 5 iOz or the like is formed.

The lower magnetic body (1) may be a ferromagnetic oxide substrate such as Mn-Zn ferrite or Ni-Zn ferrite, or Fe-Ni on a non-magnetic substrate such as ceramic.
system alloy (permalloy) and Fe-Affi-3i system alloy (
Composite substrates laminated with ferromagnetic metal materials such as Sendust),
Alternatively, a composite substrate in which a ferromagnetic metal material such as Permalloy or Sendust is laminated on the ferromagnetic oxide substrate is used.

Further, on the first insulating layer (2), a first coil conductor (3) made of a metal conductor such as Cu or A1 is pattern-etched in a spiral shape (four turns in this example) at predetermined intervals. .

Here, in the present invention, the first coil conductor (3)
At the time of pattern etching, the etching is carried out using photolithography technology so that a marker film (4) having a width within the permissible error in groove depth remains.

Further, a second insulating layer (7) is formed to cover the first coil conductor (3), and a second insulating layer (7) is formed to cover the first coil conductor (3).
A spiral coil having the same winding direction as 3) and electrically connected to the first coil conductor (3) through a contact window (8) formed in the second insulating layer (7). A second coil conductor (9) having a shape (three turns in this embodiment) is formed. In other words, the coil conductor of this embodiment has a spiral two-layer, seven-turn winding structure. Further, a third insulating layer (10) is formed on the second coil conductor (9) in order to insulate it from an upper magnetic body (12), which will be described later.

The coil conductors (3) and (9) are not limited to the spiral multilayer type, but may have any S-wire structure such as a helical type or a zigzag type.

Furthermore, a gap spacer (11) made of Ta205 or the like in the front gap portion and the third insulating layer (10)
An upper magnetic body (12) made of a ferromagnetic metal material such as sendust or permalloy is formed to cover the trunk and have a predetermined trunk width. Therefore, by supplying drive current to the coil conductors (3) and (9),
The lower magnetic body and the upper magnetic body (12) cooperate to form a magnetic circuit, and are configured to perform recording and reproduction.

Furthermore, although not shown, the upper magnetic body (12)
A protective film made of 5i02 etc. is formed so as to cover the surface, etc., and this protective film is made by melting and filling an adhesive material such as glass. A protective plate made of material is fused and bonded onto the adhesive.

Thin I configured like this! In the 2M Ki head,
By providing the marker film (4), the processing accuracy of groove processing for regulating the contact width with the magnetic recording medium is greatly improved.

The marker film (4) formed in the thin film magnetic head of the present invention will be described in detail below.

As shown in FIG. 2, the marker film (4) has a rectangular shape, for example, and has opposing sides (4a).

(4b) is the depth rear end position (Ib) (depth length pp=
0) It is formed parallel to the line.

Further, if the groove depth is a and the tolerance range of the groove depth position (5a) (the position where the predetermined groove depth a is achieved) is 8b, then the center line of the marker film (4) ( b=o) matches the predetermined groove depth a, and the length of the marker film (4) in the direction X of the magnetic recording medium sealing surface is within the above-mentioned tolerance ±b. In addition, the above marker film (4
) is not limited to a rectangle, and may be any shape such as a trapezoid, square, or parallelogram as long as it has a pair of parallel sides.

Therefore, the lower limit of the depth a is reached when the - side (4b) of the marker film (4) is exposed on the processed surface by cutting a groove with a grindstone or the like. ) becomes the upper limit of the marker film (4) when the - side (4a) becomes invisible. That is, if the marker film (4) is exposed on the processed surface in the groove processing step, /#
It is confirmed that the depth a is within the tolerance ±b.

One possible method is to form a single film and measure the length of the marker film exposed on the machined surface after groove processing to detect the absolute groove depth. However, since a grindstone is usually used for this groove processing,
The machined surface will not be smooth. Therefore, errors tend to occur in measuring the length of the marker film, and the groove depth cannot be detected with high accuracy. Furthermore, when attempting to measure the length of the marker film on a processing machine, it is necessary to change the set value of the groove depth, which may conversely reduce the groove processing accuracy.

In this way, in the groove machining that requires simultaneous machining precision,
In the thin film magnetic head of the present invention, it is possible to determine whether the groove depth is within the tolerance by simply checking the presence or absence of the marker film (4) exposed on the processed surface. therefore,
In the groove machining described above, the depth can be checked with high accuracy with the thin film magnetic head attached to the groove machining machine. Also, you only need to check the presence or absence of the marker film (4), so
There is no need to use a high-magnification microscope. In particular, the marker film (4) of the present invention is effective when polishing a block piece having a plurality of thin film magnetic head elements.

In this example, the marker film (4) was formed simultaneously with the formation of the first coil conductor (3), but it goes without saying that it may be formed simultaneously with the formation of the second coil conductor (9).

Furthermore, it goes without saying that the present invention is not limited to the above-described embodiments, and that various structures can be adopted without departing from the spirit of the present invention.

〔Effect of the invention〕

As is clear from the above description, in the thin film magnetic head of the present invention, a marker film is formed on the lower magnetic body to ensure the accuracy of the depth of the groove that regulates the contact width with the magnetic recording medium. Therefore, the groove processing for regulating the contact width can be performed while checking the presence or absence of the marker film exposed on the processed surface.

Therefore, the groove machining described above can be performed easily and with high precision.

[Brief explanation of the drawing]

FIG. 1(A) is a schematic plan view showing an example of a thin film magnetic head according to the present invention, and FIG. 1(B) is a-a of FIG. 1(A).
It is a cross-sectional view taken along the a line. FIG. 2 is an enlarged plan view showing the vicinity of the marker membrane. l... Lower magnetic body 3... First coil conductor 4... Marker film 9... Second coil conductor 12... Upper magnetic body

Claims (1)

[Claims] A thin film magnetic head in which a coil conductor and an upper magnetic body are laminated on a substrate with an insulating layer interposed therebetween, and grooves are formed to regulate the contact width with a magnetic recording medium. A thin film magnetic head characterized in that a marker film is formed on the lower magnetic body to ensure the depth accuracy of the groove processing.