JPH07101486B2 - Processing amount detection marker and method of manufacturing thin film magnetic head using the marker - Google Patents

Description

The present invention relates to a structure and a manufacturing method of a thin film magnetic head suitable for high density magnetic recording or reproduction, and more specifically, to a magnetic field of a magnetic head. The present invention relates to a marker for detecting a processing amount in a process of polishing a portion facing a recording medium into a predetermined shape, and a magnetic head manufacturing method using the detection marker.

(B) Conventional technology A thin film magnetic head is manufactured by vacuum deposition or sputtering,
Using a thin film forming technique such as photolithography, a thin film forming a magnetic circuit, a conductor coil, an electrode, etc. is laminated on an insulating layer via an insulating layer, and compared with a conventional bulk type magnetic head, It has the advantage of being easy to miniaturize and increase the density.

However, in the thin film magnetic head, the depth dimension (gap depth) of the magnetic gap in the direction orthogonal to the magnetic recording medium surface is extremely smaller than that of the bulk type magnetic head.
When polishing the surface facing the magnetic recording medium, a high processing accuracy of, for example, 1 μm or less is required.

Therefore, in Japanese Utility Model Publication No. 62-35133 (G11B5 / 31), as shown in FIG. 8, a magnetic core (5) and a coil conductor (2) are used.
There has been proposed a magnetic head in which a pair of markers (4) and (4) for detecting a processing amount are formed by a thin film on the upper surface of a substrate (1) provided with (3) and the like.

Each of the markers (4) and (4) has an outer shape of an isosceles right triangle, and the positions of the vertices of the triangles connect the end positions (5a) and (5a) of the magnetic gap parts in the gap depth direction.
-The line A coincides with the line A and the base of the triangle is orthogonal to the working direction.

In the manufacturing process of the magnetic head, for example, B- in the figure
By measuring the widths Wa and Wb of both marker films when the polishing process has proceeded to the position of the line B, the gap depth Dg at that time can be calculated by utilizing the triangle similarity of the markers. Further, when there is a difference between the two measured values Wa and Wb, the inclination angle of the machined surface with respect to the line AA can be known from the deviation.

However, in the above thin-film magnetic head, the width of the marker
Calculate the gap depth based only on the measured values of Wa and Wb,
Since the processing is completed when the predetermined gap depth is obtained, when the triangle of the marker is broken due to chipping or plastic deformation of the marker itself during polishing, the measured values of the widths Wa and Wb and the gap depth The proportional relationship is lost, and a large error occurs in the gap depth after processing is completed.

Providing a large number of markers to solve this problem leads to an increase in size of the magnetic head.

On the other hand, in Japanese Unexamined Patent Publication No. 62-232718 (G11B5 / 31), a pair of marker films are formed in a vertical positional relationship on a substrate, and the width of one marker film appearing on a polished surface is measured. Has proposed a thin film magnetic head capable of calculating the gap depth. However, in the magnetic head, there is a problem that it is not possible to know the amount of processing residual during processing.

(C) Problems to be Solved by the Invention The present invention has been made in view of the drawbacks of the above-mentioned conventional examples,
Even if the shape is deformed to some extent due to deformation during processing, it is possible to easily and easily maintain the state where the processing has not reached the predetermined amount, the time when the processing has reached the predetermined position, and the state where the processing has advanced beyond the predetermined position. An object of the present invention is to provide a processing amount detection marker that can be accurately detected, and a method of manufacturing a thin film magnetic head using the marker.

It is another object of the present invention to provide a detection marker capable of highly accurately measuring a processing residual amount or an excessive processing amount in a processing step, and a method of manufacturing a thin film magnetic head using the detection marker.

(D) Means for Solving the Problems In the processing amount detection marker of the present invention, a first and a second marker layer each having a predetermined planar shape on the upper surface of the substrate are formed by the first marker layer only. A detection part, a second detection part consisting only of the second marker layer, and the first and second
Of the marker layers are stacked so as to form a third detection portion, and a boundary line between the second detection portion and the third detection portion is formed among the contour sides that form the outer shapes of the both marker layers. The contour side (7d) and the contour side (8d) that forms the boundary line between the first detection unit and the third detection unit intersect with each other, and at least one of these contour sides is the machining progress direction. It is characterized in that it is inclined by a predetermined angle with respect to and the intersection point of these contour sides is arranged at a predetermined processing end position.

Further, in the machining amount detection marker of the present invention, the contour sides (7d) and (8d) are both inclined with respect to the machining proceeding direction, and are formed by the intersection of the contour sides (7d) and (8d). Located in front of and behind the machining direction in one of the two areas 2
The third detector is arranged in either one of the two regions.

Further, in the machining amount detection marker of the present invention, the first marker layer and the second marker layer are parallel to each other through the intersection of the contour sides (7d) and (8d). It is characterized by being line-symmetric with respect to a virtual line.

Furthermore, the marker for processing amount detection of the present invention is characterized in that the first marker layer and the second marker layer are formed of a conductive material, and an insulating layer is interposed between both marker layers. To do.

Further, the method for manufacturing a thin film magnetic head of the present invention is characterized in that the polishing process for forming the portion facing the recording medium is carried out while observing the end face shape of the above-mentioned processing amount detecting marker which appears on the processing surface.

(E) Action According to the processing amount detection marker having the above-described configuration and the thin-film magnetic head manufacturing method using the marker, when the processing is performed before reaching the predetermined position or when the processing is performed beyond the predetermined position. Is capable of visually judging which processing is in progress based on the presence or absence of an overlapping portion of a pair of marker layers appearing on the processing surface, and at least one marker having a side inclined with respect to the processing progress direction. By measuring the width of the layer, the gap depth and the residual machining amount at that time can be calculated with high accuracy.

When the machining progresses to a predetermined position, the end faces of both marker layers appearing on the machining surface are in a state of abutting each other with the intersection point representing the machining end position as a contact point, and this state can be detected visually accurately. I can.

Further, even if the marker is deformed to some extent due to the processing, there is no change in the overlapping state of the pair of marker layers in the above-mentioned three processing steps, so that each processing step can be accurately known.

(F) Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

The thin-film magnetic head of the present embodiment has a plurality of magnetic head portions including first and second conductor coil layers (2) and (3) and an upper magnetic core (5) as shown in FIG. A multi-track type magnetic head arrayed in the left-right direction in the figure), and the gap depth Dg of each head part is set to a predetermined value by polishing the Z-direction in the figure to the position of the DD line. To be done.

FIG. 7 shows the structure of the magnetic head portion after the polishing process, in which the lower magnetic core (51) made of Sendust and the gap spacer (9) are formed on the magnetic or non-magnetic substrate (1). the first insulating layer made of SiO ₂ to (91), the first conductor coil layer made of Cu (2), the second insulating layer made of SiO ₂ (92), the second conductor coil layer made of Cu (3), SiO _{A second} insulating layer (93) made of ₂ and an upper magnetic core (5) made of Sendust are sequentially laminated.

Further, a protective plate (11) made of non-magnetic ceramic is provided on the upper surface of the laminate through a bonding layer (95) made of glass or synthetic resin.

The gap spacer (9) sandwiched by the upper magnetic core (5) and the lower magnetic core (51) is exposed at the medium facing surface (12) formed by the polishing process, and the magnetic gap having a predetermined gap depth Dg. Make up part.

As shown in FIG. 1, a pair of processing amount detection markers (6) (6) made of Cu are formed on both left and right ends of the substrate (1).

Each marker (6) has a first marker layer (7) having a trapezoidal outer shape and a second marker layer (7) which are symmetrical to each other as shown in the figure.
The marker layer (8) and the marker layer (8) are laminated, and the marker layer (8) is shown in FIG.
And, as shown in FIG. 3 (b), the first marker layer (7) is formed on the upper surface of the lower magnetic core (51), and the second marker layer (8) is interposed by the second insulating layer (92). And is formed over the first marker layer (7). Incidentally, FIG. 3 (a)
1 is a sectional view taken along the line I-I in FIG. 1, and FIG. 3 (b) is a line II- in FIG.
It is a II sectional view.

As shown in FIGS. 1 and 2, the outer shapes of both the marker layers (7) and (8) are the gap depth direction, that is, the machining progress direction Z.
First contour sides (7a) and (8a) orthogonal to the first contour sides, and second contour sides (7b) and (8b) and third contour sides ( 7c) (7c),
A trapezoid composed of a fourth contour side (7d) (8d) inclined by a predetermined angle with respect to the gap depth direction, and aligning the first contour sides (7a) (8a) of both marker layers on the same line, Moreover, the fourth contour sides (7d) ((d) are arranged so as to intersect each other.

Therefore, in each of the detection markers (6), a first detection part (6a) consisting only of the first marker layer (7) and a second detection part (6b) consisting only of the second marker layer (8), A third detection portion (6c) in which both marker layers overlap is formed.

That is, the third detection unit (6c) is configured to have the fourth contour side (7d).
It is located in front of the machining direction Z among the four regions formed by the intersection of (8d). The boundary line between the first detection unit (6a) and the second detection unit (6b) is formed by a part of the fourth contour side (8d) of the second marker layer (8), and the second detection unit The boundary line between (6b) and the third detection section (6c) is constituted by a part of the fourth contour side (7d) of the first marker layer (7).

The intersection P of the second contour side (7b) and the fourth contour side (7d) of the first marker layer (7), and the second contour side (8b) and the fourth contour side (8d) of the second marker layer (8). ), The intersection point P'is the gap depth end (5a) (5
The straight line FF connecting the line a) is aligned with the line Q, and the intersection Q of the fourth contour sides (7d) and (8d) is aligned with the line D-D representing the polishing end position in FIG. There is. The first marker layer (7) and the second marker layer (8) are line-symmetric with respect to an imaginary line (not shown) that passes through the intersection Q and is parallel to the machining progress direction Z.

In addition, in consideration of the convenience of gap depth calculation described later, the fourth
The inclination angle θ of the contour sides (7d) and (8d) is the second from the point Q.
The vertical distance Lp to the contour sides (7b) and (8b) is defined to be approximately 63 degrees so as to be twice the distance Ls from the point Q to the point P along the Z direction.

Next, a method of manufacturing the thin film magnetic head will be described with reference to FIGS. 1 and 7.

First, a ferromagnetic metal thin film made of sendust or the like is formed by vacuum deposition or sputtering on the entire upper surface of a substrate (1) made of a non-magnetic material such as crystallized glass or a magnetic material such as ferrite. The thin film is processed into a predetermined shape by photoetching to form a lower magnetic core (51) made of a ferromagnetic material, and further the lower magnetic core (5
A first insulating layer (91) made of SiO ₂ is formed on the entire upper surface of 1).

By depositing a Cu film having a thickness of 2 μm on the entire upper surface of the first insulating layer (91) and then subjecting the Cu film to ion beam etching, the first conductor coil layer (2) and the first marker layer ( 7) is formed at the same time.

Next, a second insulating layer (92) made of SiO _{2 is} formed on the entire surface of the substrate to a thickness of 1 μm, and then a second insulating layer (92) is formed on the entire surface to a thickness of 2 μm.
By depositing a Cu film of μ and subjecting the Cu film to ion beam etching, the second conductor coil layer (3) and the second marker layer (8) are simultaneously formed.

After that, on the surface of the substrate, as is well known, a third layer made of SiO _{2 is formed} .
An insulating layer (93) and an upper magnetic core (5) are formed, and a protective plate (11) is bonded to the surface of the insulating layer (93) and a bonding layer (95) to manufacture a magnetic head assembly.

Finally, the end face (10) of the magnetic head assembly is subjected to a polishing process using a known tape-like polishing tool to form a face (12) facing the magnetic recording medium, whereby a predetermined gap depth Dg is obtained. A thin-film magnetic head having is completed.

The polishing step is carried out while observing the end surface shape of the detection markers (6) (6) appearing on the processed surface with a magnifying glass or the like as described later.

That is, when the polishing proceeds to the line C-C in Fig. 2, as shown in Fig. 4 (a), the first marker layer (7) is formed on the processed surface.
Only the first detection part (6a), the third detection part (6c) in which the first and second marker layers (7) and (8) overlap each other,
Also, the second detection part (6b) of only the second marker layer (8) is observed, and it is apparent that the polishing has not reached the predetermined processing depth.

The amount of processing from the start of polishing at this point can be calculated by measuring the width Sa of the first marker layer (7) and the width Ta of the second marker layer (8). , Ta, the measurement error due to the deformation of the marker films (7) and (8) can be offset. Further, by measuring the width F of the third detector (6c), the residual polishing amount g shown in FIG. 2 can be easily obtained from the relationship of g = F / 4.

Furthermore, when the machined surface is tilted, both measured values S
Since a deviation occurs between a and Ta, the inclination of the machined surface can be corrected based on the deviation.

After that, when the polishing progresses to the line D-D in FIG. 2, the third detector (6c) disappears from the machined surface as shown in FIG. 4 (b), and the first detector (6a) and the second detector (6a) are removed. It can be seen that the detection portion (6b) and the detection portion (6b) abut each other at one point, and at a glance a predetermined gap depth is obtained. At this time, even if the marker layers (7) and (8) are deformed due to processing, the state in which both marker layers are in contact with each other is maintained, so that the processing end point can be accurately detected.

The gap depth Dg at this time can be calculated from the measured values Sb and Tb of the widths of the first detection unit (6a) and the second detection unit (6b). For example, when there is no difference between the two measurement values, Dg = Sb / 2 can be obtained.

The polishing is completed at this point, but when the processing further progresses to the line EE in FIG. 2 due to the polishing conditions or the like, or when the completed magnetic head is installed in the recording / reproducing apparatus and used for a long time, When the facing surface is worn, it is observed that the first detecting portion (6a) and the second detecting portion (6b) are separated from each other on the processed surface or the medium facing surface, as shown in FIG. 4 (c). At first glance, it can be seen that the gap depth is below the predetermined value.

In addition, the machining excess amount or the head wear amount is calculated based on the measured values of the widths Sc and Tc of the first detection unit (6a) and the second detection unit (6b) or the distance H between the detection units. Can be done. For example, the processing excess amount h shown in FIG. 2 can be obtained by the relationship of h = H / 4.

FIG. 5 shows another configuration example of the marker (6),
A fourth contour side (7d) is provided on each of the end faces of the first marker layer (7) and the second marker layer (8) facing the processing direction.
Fifth contour sides (7e) and (8e) parallel to (8d) are formed so that each marker layer has a pentagonal outer shape. The dimensions of each part of the detection marker (6) are shown in the figure.

According to the detection marker (6) in FIG. 5, it is possible to calculate the amount of residual polishing at the initial stage of machining, that is, at the stage when machining reaches the depth where the fifth contour sides (7e) and (8e) intersect. I can.

Further, as shown in FIGS. 6 (a) and 6 (b), the third detector (6c)
The same effect can be obtained by forming at either the front side or the rear side of the point Q along the working direction.

As described above, it is possible to detect the progress stage of processing based only on the pattern of the end surface of the marker appearing on the processed surface, not only in the case of the visual polishing method, but also the realization of an automatic polishing apparatus having a pattern recognition function. It produces an excellent effect.

(G) Effect of the Invention According to the present invention, a processing amount detection marker capable of easily and accurately detecting a processing position even if the shape is slightly deformed due to deformation during processing and a thin film magnetic using the marker. A method of manufacturing a head can be provided.

Further, according to the present invention, it is possible to provide a processing amount detection marker capable of highly accurately measuring a processing residual amount or a processing excessive amount in a processing step, and a method of manufacturing a thin film magnetic head using the marker.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 7 relate to the present invention, FIG. 1 is a top view of a substrate on which a processing amount detection marker is formed, and FIG. 2 is a top view of a processing amount detection marker. 3, FIG. 3 is a sectional view of an essential part of FIG. 1, FIG. 4 is a view showing an end face of a machining amount detection marker, FIG. 5 is a diagram showing another embodiment of the machining amount detection marker, and FIG. FIG. 7 is a view showing the arrangement of the processing amount detecting markers, and FIG. 7 is a cross-sectional view of the main parts of the thin film magnetic head. FIG. 8 is a top view of a substrate on which a conventional processing amount detection marker is formed. (1) ... substrate, (2) ... first conductor coil layer, (3)
...... Second conductor coil layer, (6) …… Processing amount detection marker, (6a) …… First detection part, (6b) …… Second detection part,
(6c) …… Third detector, (7) …… First marker layer,
(8) ... Second marker layer, (7d) (8d) ... fourth contour side, (92) ... second insulating layer, (12) ... medium facing surface, Q
…… Intersection, Z …… Processing direction

Claims (6)

[Claims] 1. A marker for detecting a processing amount when polishing a portion of a thin film magnetic head facing a magnetic recording medium, wherein first and second marker layers each having a predetermined planar shape are provided. A first detection part composed only of the first marker layer, and a second detection part composed only of the second marker layer,
The first and second marker layers are laminated so as to form a third detection section that overlaps with each other, and a second detection section and a third detection section among the contour sides that form the outer shapes of both marker layers. The contour side (7d) that forms the boundary line of the above and the contour side (8d) that forms the boundary line between the first detection unit and the third detection unit intersect each other, and at least one of these contour sides A machining amount detecting marker characterized in that the contour sides are inclined by a predetermined angle with respect to the machining proceeding direction, and the intersections of these contour sides are arranged at predetermined machining end positions. 2. The contour sides (7d) (8d) are both inclined with respect to the machining progress direction, and the machining progress among the four regions formed by the intersection of the contour sides (7d) (8d). The third detection unit is arranged in either one of two regions located in front of and behind the direction.
Marker for the processing amount detection described. 3. The first marker layer and the second marker layer are line-symmetric with respect to each other with respect to an imaginary line passing through the intersection of the contour sides (7d) and (8d) and parallel to the machining progress direction. The processing amount detecting marker according to claim 2, wherein 4. The processing according to claim 1, wherein the first marker layer and the second marker layer are made of a conductive material, and an insulating layer is interposed between both marker layers. Quantity detection marker. 5. A thin film forming step of laminating a lower magnetic core, a coil conductor, and an upper magnetic core on a substrate through an insulating layer,
In a method of manufacturing a thin film magnetic head, which comprises a processing step of forming a facing portion to a magnetic recording medium in a magnetic head assembly obtained through the steps, a processing amount in the processing step in the thin film forming step. A marker for detecting the first marker, the marker includes first and second marker layers each having a predetermined planar shape, a first detector that includes only the first marker layer, and the second marker. A second detector consisting of only layers,
The first and second marker layers are laminated so as to form a third detection section that overlaps with each other, and a second detection section and a third detection section among the contour sides that form the outer shapes of both marker layers. The contour side (7d) that forms the boundary line of the above and the contour side (8d) that forms the boundary line between the first detection unit and the third detection unit intersect each other, and at least one of these contour sides The contour side is inclined by a predetermined angle with respect to the machining progress direction, and the intersection point of these contour sides is arranged at a predetermined machining end position. The machining process observes the end face shape of the marker appearing on the machining surface. A method for manufacturing a thin-film magnetic head, characterized in that the step is advanced until the intersection is detected. 6. The thin film forming step comprises a first step of simultaneously forming a first marker layer and a first conductor coil layer with the same material, and an insulating layer on the upper surface of the first marker layer and the first conductor coil layer. A second step of forming and a third step of simultaneously forming a second marker layer and a second conductor coil layer on the upper surface of the insulating layer with the same material, and a coil conductor is formed by the first and second conductor coil layers. The method of manufacturing a thin film magnetic head according to claim 5, wherein the thin film magnetic head is formed.