JP2793847B2 - Thin film magnetic head and method of manufacturing the same - Google Patents

Description

The present invention relates to a thin-film magnetic head and a method for manufacturing the same.
In particular, the present invention relates to a thin-film magnetic head capable of forming a high-precision floating surface by improving a method of manufacturing a floating magnetic head and a method of manufacturing the same.

[Prior Art] In recent years, so-called thin-film magnetic heads, in which a magnetic circuit and a recording / reproducing coil are formed by using a thin-film forming technique such as vapor deposition and sputtering and a pattern forming technique by etching, have been reduced in cost and improved in performance. Has been requested. In order to apply this magnetic head to a magnetic disk device or the like as a floating magnetic head, and to realize high-density recording and low cost, for example, a plurality of conversion elements are collectively formed on a substrate, and each conversion element is formed for each conversion element. And a plurality of thin-film magnetic head chips are obtained from one substrate. At this time, high-precision specifications are required everywhere from the conversion element forming step to the chip forming step. Therefore, it is very important to establish the manufacturing technology and manufacturing process.

Therefore, as a technique for reducing the cost and stabilizing the accuracy, for example, a method for manufacturing a thin-film magnetic head is disclosed in Japanese Patent Application Laid-Open No. 62-95716. This manufacturing method will be described with reference to FIGS. 11 and 12. FIG. 11 is a plan view showing an arrangement state of the conversion elements 2 arranged and formed on the substrate 1. FIG. here,
The conversion elements 2 are collectively formed in a matrix on a substrate 1 made of silicon, ceramic, or the like, using a thin film forming technique and a pattern forming technique. Next, the conversion element groups arranged in the column direction on the substrate 1 in which the conversion element groups are formed in a matrix as described above are defined as unit rows 20, and a cutter blade or the like is used for each unit row 20 in FIG. Cut along the broken line to obtain a head block 11. FIG. 12 shows a perspective view of the head block 11 after cutting. From the state of the head block 11, a groove 21 for coupling with the head support mechanism is machined, and the flying surface 13 is precisely polished. Here, the groove 21 and the floating surface 13 are collectively processed and polished to form the gap depth 10 with high precision. Thereafter, the thin-film magnetic head is manufactured in such a manner that the thin-film magnetic head 14 is obtained by dividing the necessary units (chips) along the dotted line in FIG.

Further, as a technique for improving the flatness of the air bearing surface particularly by another manufacturing process, there is a magnetic head manufacturing method disclosed in Japanese Patent Application Laid-Open No. 63-191309, for example. This manufacturing method will be described with reference to FIGS. No.
FIG. 13 shows a manufacturing process of the magnetic head, and FIGS. 14 and 15 show a state of an intermediate process in the manufacturing process. Thus, the head block 11 cut out from the substrate (the conversion element is not shown) is first adhered to the processing jig 22 on the surface (front surface) serving as the floating surface (131, 132), and the back surface 23 of the head block 11 is processed (133). ). Next, the head block 11 is peeled off from the processing jig 22 (having the whetstone escape groove 22a), turned upside down (134), adhered again to the processing jig 22 (135), and
13 is ground and the groove 24 is processed (136). Thereafter, each magnetic head 14 is cut into a plurality of pieces at positions corresponding to the escape grooves 22a (137). By this cutting, the processing distortion generated in the groove processing step 136 is released to some extent. next,
The workpiece is aged at about 50 ° C. to 65 ° C. for about 2 to 10 hours while being cut and adhered to the processing jig 22 to remove the processing strain generated in the step 136 (138).
Thereafter, the air bearing surface 13 is polished (139), finished to a high degree of flatness, and then separated from the processing jig 22 (140) to obtain a magnetic head 14 (141). I was

[Problems to be Solved by the Invention] Each of the above-described conventional technologies has the following problems.

First, in the method of manufacturing a thin-film magnetic head described in Japanese Patent Application Laid-Open No. 62-95716, for example, after a plurality of conversion elements 2 are formed on a substrate 1, the conversion elements 2 are subsequently protected. Then, at a heat treatment temperature of about 300 to 400 ° C., an insulating film or the like (not shown) is formed in a uniform thickness over the entire substrate surface including the conversion element, and then cut in block units, air bearing surface polishing, and head. In the case of a thin film magnetic head that performs cutting for each unit, the air bearing surface is polished in the state of a head block in which a plurality of conversion elements are aligned, and the gap depth and flatness are formed with high precision, and then each magnetic head unit This is a step of cutting each (one or two conversion elements). For this reason, stress distortion caused by the difference in thermal expansion coefficient between the substrate and the insulating film during the formation of the insulating film is released after the cutting, and the flatness of the air bearing surface, which is finished with high precision, is equal to the substrate portion and the insulating film. 0.05 locally between
Causes deformation of about 0.1 μm. This deformation not only greatly impairs the performance as a magnetic head when the flying height of the floating magnetic head is controlled with submicron precision, but also causes mechanical contact with the recording medium (head crash).
And may lead to catastrophic failure.

Next, in the method of manufacturing a magnetic head disclosed in Japanese Patent Application Laid-Open No. 63-191309, which is disclosed as a means for solving the problems of the prior art, a head block is cut for each magnetic head unit (one or two conversion elements). , By aging,
The stress distortion generated in the air bearing surface grinding / grooving process 136 is released, and then the air bearing surface is polished to finish the flatness with high accuracy, so that the flatness is maintained in a good state in the completed state of the magnetic head. You. However, in order to obtain high-precision flatness, it is necessary to finally polish the air bearing surface after passing through various processing and aging steps, and the processing step is fixed (steps in another order). It cannot be taken.)
For example, in the case of a floating magnetic head, when it becomes necessary to control the subtle flying height of a submicron with a high precision, the rail shape (groove 24
Width, depth, spacing, position, etc.) must be handled by forming them in a very high precision and special shape. If conventional machining techniques cannot be used, patterning techniques such as etching must be used. May be used. In this case, it is not possible to form the rail with high precision while the air bearing surface 13 is rough-cut,
It is more advantageous to perform the rail formation (formation of the groove 24) after polishing the air bearing surface 13 and finishing the flatness with high precision. However, in the conventional technology, when rails are formed, since each magnetic head unit is already cut and formed as a single unit, mass production is difficult if a rail is formed with a single magnetic head unit,
Even if the magnetic heads are united into a plurality and formed collectively, it is difficult to form rails with ultra-high accuracy due to problems such as misalignment between the magnetic heads.

Further, as a problem common to the above two prior arts, when cutting is performed for each magnetic head unit, the insulating film is likely to be chipped or cracked, and the boundary between the substrate and the insulating film may be peeled. is there. Further, in a later manufacturing process, the insulating film is easily chipped due to handling, contact with a jig, or the like, which deteriorates the manufacturing yield and makes it difficult to reduce the cost.

Accordingly, a first object of the present invention is to release high-precision air bearing surface flatness in a head block state by releasing stress strain generated at the time of forming an insulating film in an initial step. An object of the present invention is to provide a thin-film magnetic head having high reliability without causing deformation based on the magnetic head and a method for manufacturing the same.

A second object of the present invention is to eliminate defects in an insulating film generated when cutting each magnetic head unit, to reduce chipping or cracks in the insulating film in a subsequent manufacturing process, and to improve manufacturing yield and mass productivity. It is an object of the present invention to provide a thin-film magnetic head and a method for manufacturing the same, which can increase the cost and reduce the cost.

[Means for Solving the Problems] In order to achieve the first object, the method of manufacturing a thin-film magnetic head according to the present invention comprises the steps of: (a) forming a plurality of transducers and an insulating film aligned on a predetermined surface of a substrate; And (b) forming a groove having a depth at least over the entire thickness of the insulating film in advance at a position where cutting is to be performed for each magnetic head unit on the substrate. A step of separating only the insulating film for each head unit (with the substrate connected);
(C) cutting the plurality of conversion elements together with the substrate for each row in the alignment direction to form a head block; and (d) recording medium facing surface (conversion) orthogonal to the formation surface of the conversion element and the insulating film in the head block. Polishing the surface of the element on the side where the magnetic gaps are aligned) to form a predetermined gap depth and flatness, and (e) thereafter, cutting the head block for each magnetic head unit And a process. The step (c) is necessary when the conversion elements are arranged vertically and horizontally on the substrate (two-dimensionally). However, when the conversion elements are arranged on the substrate only in one direction (one-dimensionally), it is omitted. Good. Further, between the steps (d) and (e), if necessary, a step of forming a rail for regulating the flying height on the flying surface of the head block so as to correspond to each conversion element may be inserted. it can.

In order to achieve the second object, the thin-film magnetic head of the present invention has a structure in which a plurality of conversion elements and an insulating film are formed on a predetermined surface of a substrate, and this is cut (divided) into units of each magnetic head. Then, the ridge of the conversion element forming surface of the magnetic head at the cut portion is formed in a stepped shape. The stepped shape is formed at least over the entire thickness of the insulating film.

In order to manufacture such a thin film magnetic head,
In the manufacturing method, during the step (b), the width of a groove previously formed in the insulating film (or in the insulating film and the substrate)
The cutting width is made wider than the cutting width when cutting for each magnetic head unit in the step (e). After that, when the step (e) is performed after various steps, by cutting along the center of the groove, the insulating film ridge on the conversion element forming surface is formed on the substrate in each thin film magnetic unit. An exposed stepped or chamfered shape (shoulder) is formed.

[Operation] An operation based on the above configuration will be described.

The groove previously formed in the insulating film (and a part of the substrate) at the position where the substrate is cut for each magnetic head unit,
As a result, the insulating film is separated for each conversion element. As a result, stress distortion caused by a difference in thermal expansion coefficient between the substrate and the insulating film when the insulating film is formed is released. In that state, after cutting into a head block, the flatness of the air bearing surface is polished with high precision, but at that time, the substrate remains connected,
Since a plurality of magnetic head units are simultaneously polished, a plurality of magnetic head units having a floating surface with high precision flatness can be obtained at the same time, thereby improving workability and mass productivity. After that, after various steps such as formation of a flying height control rail, cutting is performed along the previously formed groove for each magnetic head unit, but at this time, only the substrate is cut without cutting the insulating film. Is cut off, the stress strain of the insulating film is not released by the cutting, the flatness of the air bearing surface does not change (deform), and the high-precision flatness is maintained even in the completed state of the thin-film magnetic head.

Further, by making the groove width wider than the cutting width and cutting along the center of the groove, damage to the insulating film at the time of cutting is eliminated, and in the completed state,
According to the processing method, the ridge portion of the insulating film is stepped, and as a result, the insulating film is formed in a concave shape inside the surface,
Chipping of the insulating film, generation of cracks and the like can be reduced.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 6 and FIG.
This will be described with reference to the drawings.

FIG. 1 is a perspective view of a conversion element group formed on a substrate, and FIG. 2 is a cross-sectional view of the conversion element section. 3 to 5 show a state diagram of an intermediate step in the process of manufacturing the thin-film magnetic head, and FIG. 6 shows a perspective view of a completed state of the thin-film magnetic head. FIG. 8 is an explanatory view summarizing a series of manufacturing steps from FIG. 1 to FIG. First, in FIGS. 1 and 2, a lower insulating film 3a is formed on the substrate 1 with a uniform thickness over the entire substrate, and then a lower magnetic film 4a, a recording / reproducing coil 5, and an upper magnetic film 4b are formed by lamination, respectively. Then, a plurality of aligned conversion elements 2 are formed (801). Also, a lead wire 6 is connected to each recording / reproducing coil 5 and a terminal 7 is formed at the end thereof. Thereafter, the upper insulating film 3b is formed with a uniform thickness over the entire substrate so as to protect the conversion element 2 (80).
2). These are formed at a high temperature by making full use of thin film forming techniques such as vapor deposition and sputtering and pattern forming techniques such as etching. Next, an insulating film separation groove 8 is formed by mechanical grinding in accordance with the position at which each conversion element 2 is cut in a later step (803). At this time, it is desirable that the depth of the insulating film separating groove 8 is larger than the total thickness of the lower insulating film 3a and the upper insulating film 3b and is slightly penetrated into the substrate 1. By forming the insulating film separation groove, the insulating films 3a and 3b formed integrally with the adjacent conversion elements 2 are separated and connected to the substrate 1 individually. Next, the insulating films 3a and 3b and the substrate 1 are cut along the broken line 9, and as shown in FIG. 3, a head block 11 in which a plurality of conversion elements 2 are formed in a horizontal row is formed (804). . Here, the portion of the substrate 1 including the conversion element 2 between the insulating film separation grooves 8 is a portion that will eventually become the thin-film magnetic head 14. From the state of the head block 11, the air bearing surface 13 is precisely polished to the broken line portion 12, thereby finishing the gap depth 10 and the flatness of the plurality of thin film magnetic heads 14 with high accuracy (805). Next, as shown in FIG. 4, a rail 15 for controlling the flying height is formed on the flying surface 13 of the head block 11 with high precision by using a pattern forming technique such as mechanical grinding or etching. Each is formed on the head 14 (806). Next, as shown in FIG. 5, the head block 11 on which the rail 15 is formed is cut off for each thin film magnetic head 14 (807, 808). Here, the head block 11 is cut by a cutter along the center line 18 of the insulating film separating groove 8 already formed in the previous step and with a cutter thinner than the width of the insulating film separating groove 8, and a plurality of thin film magnetic layers are cut. Get Head 14. As a result, as shown in FIG. 6, in the separated thin film magnetic head 14 alone, a step (shoulder) 17 is formed by the insulating film separation groove 8 and the cut portion 16. When the insulating film separation groove 8 is formed, the step portion 17
In this example, the substrate portion 1 is formed so as to slightly penetrate the substrate 1 so as to cover at least the entire thickness of the insulating film 8, so that the substrate portion 1 is exposed when viewed from the conversion element formation surface 19 side. This is a state where the insulating films 3a and 3b are chamfered to the inside by one step.

In the thin-film magnetic head 14 manufactured by the manufacturing method controlled as described above, a plurality of conversion elements 2
After forming the insulating films 3a and 3b, the insulating film separating groove 8 is formed in the insulating films 3a and 3b.
3b, the insulating film 3 is formed deeper than the thickness of the insulating film 3b.
During the formation of the insulating films 3a and 3b, the stress strain caused by the difference in the thermal expansion coefficient between the substrate 1 and the insulating films 3a and 3b is released.
Deforms b. Thereafter, the air bearing surface is polished in the state of the head block 11 including the deformation, thereby finishing the high-precision flatness while removing an error caused by the deformation. After that, even if each thin film magnetic head 14 is cut, the cut width is cut with a cutter whose width is smaller than the width of the insulating film separation groove 8, so that the cut is made only for the substrate made of a single material. As a result, the cut has no effect on the insulating films 3a and 3b, and the thin film magnetic head 1
Even in the completed state of 4, the flatness finished with high precision can be maintained as it is.
Also, since the insulating films 3a and 3b are not cut (because the cutting width is narrow and the blade does not hit the insulating film), the insulating films 3a and 3b are not chipped at the time of cutting, and the crack or the substrate 1 Peeling can be eliminated. (Even if the insulating film is chipped in advance when the groove 8 is formed, it can be dealt with at an early stage of the process, such as removing it as a defective product, so that there is little problem. As a method, there is no problem because the insulating film can be prevented from being chipped or the like by using a pattern forming technique such as etching or a laser beam, as described later, instead of using mechanical processing.) In the state where the thin-film magnetic head 14 is separated into single pieces, a step 17 is formed at the ridge portion of the insulating films 3a and 3b, so that in the subsequent magnetic head assembly process, the magnetic head 14 comes into contact with a handling or a jig or the like. As a result, chipping of the ridges of the insulating films 3a and 3b, cracks, and the like can be reduced.

As shown in FIG. 7, when the insulating film separating groove 8 is formed, the tip of the grinding wheel is formed into a V-shape, and if the groove is formed, the insulating film 3 is completed when the thin-film magnetic head 14 is completed.
A step-like step does not occur between a, 3b and the substrate 1, and a shoulder (inclined surface) 17 with a chamfered ridge is formed. In this state, the insulating films 3a and 3a are brought into contact with each other by a handling or a jig in a magnetic head assembly process.
It is possible to further reduce chipping, cracks and the like of the ridge of b.

9 and 10 show a modification of the form of the insulating film separation groove 8,
And a thin-film magnetic head 14 formed thereby.

FIG. 9 shows a portion corresponding to a position for cutting from a substrate state to a state of a head block 11, and a groove film magnetic head 14;
Insulating film separating grooves 8 are formed in portions corresponding to the positions for cutting the insulating films, respectively. In the state of the thin film magnetic head 14 (single unit), the insulating films 3a and 3b are on both sides with respect to the air bearing surface 13 side. Also, a step 17 is formed at the ridge on the back surface side.

FIG. 10 shows the head block 11 and the thin-film magnetic head.
The insulating film separating groove 8 is formed by using a pattern forming technique such as etching at a portion corresponding to the cutting position of 14 and a portion corresponding to the position where the rail forming process of the floating surface 13 is performed. In the state of the head 14, a step 17 is formed on the ridges of all the insulating films 3a and 3b other than the ridges of the air bearing surface 13.

Both of them have further improved functions of avoiding the influence on the insulating films 3a and 3b in the processing after the step of forming the insulating film separating groove 8 and preventing chipping of the insulating films 3a and 3b, cracks and peeling. In particular, FIG. 10 shows a case where the processing of the insulating film in the subsequent process is minimized. As is clear from these examples, the shape and location of the insulating film separating groove 8 for releasing the stress strain at the time of forming the insulating films 3a and 3b may be different. It is only necessary to maintain the groove shape and the depth so that only the substrate 1 can be processed without processing the insulating films 3a and 3b, and it should not be limited to these specific forms. In addition, as a method for forming the insulating film separation groove 8, a pattern forming technique by etching or the like is used,
It may be formed by a laser beam. According to these forming methods, the insulating films 3a, 3a when forming the insulating film separating groove 8 are formed.
The damage to b can be reduced. Therefore, the groove forming method is not limited to a specific method.

[Effects of the Invention] As described above in detail, according to the present invention, after forming a plurality of conversion elements and an insulating film on a substrate, and cutting the magnetic head unit to form a thin-film magnetic head, forming the insulating film The stress strain that occurs at the time is released by the insulating film separating groove formed in advance, and then, in a head block state in which a large number of conversion elements remain connected, the air bearing surface is finished to high precision flatness, and then the substrate is (Head block) is separated and cut into individual magnetic head units. At the time of this separation and cutting, stress and strain are released and no new deformation occurs. Therefore, the air bearing surface is finished to the above-mentioned flatness with high precision. This state can be maintained even when the magnetic head unit is completed, and such high-precision polishing is simultaneously performed on a large number of magnetic head units, thereby improving workability. I do. Also, adjust the flying height in sub-micron units,
When using a rail forming means to form a specially shaped rail in order to obtain a delicate flying posture with high precision, work on low-cost rail formation with high precision according to the floating surface finished with high precision. Even when various steps such as rail formation are involved, no new deformation occurs when the magnetic head units are finally separated, and a highly reliable thin-film magnetic head can be manufactured. Has the effect that is possible.

In addition, not only in the process of obtaining each thin-film magnetic head unit, but also in the subsequent processing of the thin-film magnetic head unit and in the subsequent manufacturing process, the insulating film has another step due to the presence of the step at the ridge of the insulating film. Heads and other objects are less likely to hit, reducing the occurrence of chipping etc., improving manufacturing yield,
There is an effect that the cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a conversion element forming state according to an embodiment of the present invention, FIG. 2 is a sectional view of the conversion element, FIG. 3 is a perspective view of a head block according to the embodiment, and FIG. FIG. 5 is a perspective view of a head block on which a floating surface rail is formed according to an example, FIG. 5 is a cross-sectional view after cutting the head block according to the embodiment, FIG. 6 is a completed perspective view of a thin film magnetic head according to the embodiment, and FIG. FIG. 8 is a perspective view showing a conversion element formation state and a completed state in the case of changing the shape, FIG. 8 is an explanatory view showing a processing step according to the embodiment, and FIG. 9 shows a conversion element formation state according to another embodiment of the present invention. FIG. 10 is a completed perspective view of the thin-film magnetic head according to the embodiment, FIG. 11 to FIG. 15 are explanatory views of the prior art, FIG. 11 is a plan view of a conversion element formation state, and FIG. FIG. 13 is a perspective view of a head block, FIG. 13 is an explanatory view showing a processing step, FIG. Perspective view of Hetsudoburotsuku and the jig, FIG. 15 is a perspective view of Hetsudoburotsuku and the jig after machining. 1 ... substrate, 2 ... conversion element, 3a, 3b ... insulating film, 4a ...
... lower magnetic film, 4b ... upper magnetic film, 5 ... read / write coil, 6 ... lead wire, 7 ... terminal, 8 ... insulating film separation groove,
10 ... Gap depth, 11 ... Head block, 12 ... Polished surface, 13 ... Floating surface, 14 ... Thin film magnetic head (single unit),
15 ... rail, 16 ... cutting section, 17 ... step section.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Yoshikazu Tsuji 2880 Kozu, Kozuhara, Odawara, Kanagawa Prefecture Inside the Odawara Plant, Hitachi, Ltd. (72) Akio Takakura 2880 Kozuhara, Kozuhara, Odawara, Kanagawa, Japan 56) References JP-A-64-46216 (JP, A) JP-A-62-73411 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 5/31

Claims (2)

(57) [Claims] A step of forming a plurality of aligned transducer elements by sequentially forming a lower magnetic film, a recording / reproducing coil, and an upper magnetic film after forming a lower insulating film on the substrate with a uniform thickness over the entire substrate. Forming an upper insulating film for protecting the plurality of conversion elements over the entire area of the substrate; and, at a cutting position for each magnetic head unit, deeper than the combined thickness of the upper insulating film and the lower insulating film. Forming an insulating film separating groove to a depth that penetrates into the substrate, forming a head block in which a plurality of the conversion elements are formed in a row, and a recording medium facing surface orthogonal to a forming surface of the upper insulating film. Polishing as a floating surface to form a predetermined gap depth and flatness; and cutting the insulating film isolation groove of the head block to be thinner than the groove width, thereby forming a magnetic element on the conversion element forming surface of the magnetic head. Ridge Method of manufacturing a thin film magnetic head comprising: the step of forming the stepped shape, the. 2. A method according to claim 1, further comprising: forming a lower insulating film on the substrate with a uniform thickness over the entire substrate; forming a lower magnetic film, a recording / reproducing coil, and an upper magnetic film in order to form a plurality of aligned transducer elements; In a thin-film magnetic head in which an upper insulating film for protecting the plurality of transducers is formed over the entire substrate and cut for each magnetic head unit, a ridge on the transducer element forming surface of the magnetic head has a stepped shape. The stepped shape of the ridge is formed such that the depth of the step in the stepped shape of the ridge is deeper than the combined thickness of the upper insulating film and the lower insulating film and bites into the substrate. Wherein the substrate is exposed on the same surface as the conversion element forming surface.