JPH08273120A - Production of thin-film magnetic head - Google Patents

Abstract

PURPOSE: To obtain a process for producing a thin-film magnetic head having high accuracy and excellent mass productivity. CONSTITUTION: This process for producing the thin-film magnetic head has a stage for forming at least a lower core 2, magnetic gap 6, coil 4 and upper core 5 by subjecting the surface of a substrate 1 to a prescribed magnetic circuit forming process and a stage for subjecting this substrate to medium sliding width working exclusive of the part corresponding to a medium sliding width W by executing etching. As a result, the medium sliding width W is regulated by the etching having the high working accuracy without using machining.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film magnetic head used in a magnetic recording / reproducing apparatus such as a VTR or a magnetic disk drive.

[0002]

2. Description of the Related Art Generally, a thin film magnetic head is different from a bulk type head having a coil formed by using a wire rod.
Since it is formed by fine processing using a photolithography technique, it has low inductance and excellent frequency characteristics, and has been widely used in hard disk drive devices and the like. This type of thin film magnetic head has an advantage that a large number of thin film magnetic heads can be manufactured at one time because it is formed by repeatedly performing film formation and etching on the substrate using the photolithography technique as described above.

A structure of a conventional thin film magnetic head and a method of manufacturing the same will be described below. FIG. 9 is a plan view showing a general thin film magnetic head, and a protective substrate is not shown for clarifying the internal structure. FIG. 10 is a sectional view taken along the line I-I in FIG. 9, in which a protective substrate is shown. FIG. 11 is a side view showing the medium sliding surface which is the head tip portion of FIG. In the figure, reference numeral 1 denotes a substrate made of a semiconductor wafer, glass or the like. The surface of the substrate is subjected to film forming operations such as sputtering and CVD, polishing operation and etching operation, and is insulated by a lower core 2 made of a magnetic film and an insulating material 3A. The coil 4 and the magnetic gap 6 between the upper core and the upper and lower cores made of a magnetic film are formed. In the figure, 3B is an insulating material that covers the whole, and 7 is an electrode pad connected to the coil.
Then, the magnetic recording medium is recorded / reproduced by the magnetic field variation in the gap 6 while being in contact with the medium sliding surface 8 processed to have the medium sliding width W.

When such a thin film magnetic head is used for a VTR, a good tape touch cannot be obtained due to the asymmetrical shape with the magnetic gap 6 at the center, which may deteriorate the recording / reproducing characteristics. . Therefore, in order to improve the touch with the recording medium, a protective substrate is attached and processed into a predetermined shape to obtain good contact with the medium. Such a head structure is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-235211. 12 and 13 show two types of thin film magnetic heads provided with a protective substrate. FIGS. 12 (A) and 13 (A) are side views, and FIGS. 12 (B) and 13 (B) are respectively. The plan view, FIG. 12C, and FIG. 13C are side views of the thin-film magnetic head body.

In the illustrated example, protective substrates 9 are attached to both sides of the thin film magnetic head body 10. And
The protective substrate 9 is stepped (in the case of FIG. 12) or tapered (in the case of FIG. 13), leaving a width W corresponding to the medium contact surface 8.
By processing the magnetic recording medium, the magnetic medium and the head can be brought into contact with each other uniformly at a predetermined pressure. The processing of the protective substrate 9 is generally performed by subjecting individual heads to mechanical processing.

[0006]

By the way, in the thin film magnetic head, the distance L1 from the tip of the head to the upper portion of the coil 4 is very small as shown in an enlarged view in FIG. When processing the moving width, there was a case where the coil was broken. The precision of the machining at this time is in the unit of several μm, and it is necessary to form the groove shape having a predetermined depth with reference to the sliding contact surface 8. However, in the mass production process, as shown in FIGS. Since a large number of different heads are arranged side by side and processed,
The above-mentioned coil disconnection occurs due to the variation in the dimension from the processing bottom surface to the coil 4. Therefore, in order to avoid this coil disconnection, dimensional control at the time of processing must be strictly performed, which has been a cause of deterioration in mass productivity.

In order to avoid coil breakage, a method may be considered in which a mask is formed on the medium contact surface 8 of the head and etching is performed using a method such as ion beam or sand blasting. Forming a high mask requires a very complicated process, and likewise causes a decrease in mass productivity. As another method of avoiding the coil breakage, it is conceivable to provide the coil 4 formed in the magnetic circuit by retracting it from the magnetic gap 6, but in this case, the magnetic circuit naturally becomes long and the recording -It is not preferable because the regeneration efficiency is significantly reduced.

The present invention focuses on the above problems,
The present invention was devised to solve this problem effectively, and its purpose is to manufacture a thin film magnetic head with high precision and excellent mass productivity by processing the medium sliding width using etching processing on a substrate. To provide.

[0009]

In order to solve the above problems, the present invention provides a method of manufacturing a thin film magnetic head,
Performing a predetermined magnetic circuit forming process on a substrate to form at least a lower core, a magnetic gap, a coil, and an upper core, and etching the substrate to leave a portion corresponding to a medium sliding width. And a step of performing a medium sliding width processing.

[0010]

Since the present invention is configured as described above, the medium sliding width is processed by etching processing using a photolithography technique or the like on the substrate, not by mechanical processing. In addition, mass productivity can be improved. In this case, an etching-promoting hole is formed in advance at a predetermined position from the back surface side of the substrate, and when etching from the front surface side, etching may be performed until the etching-promoting hole is penetrated. The etching can be performed quickly, and the processing accuracy can be kept high even if the selection ratio at the time of etching is small.

Further, by using a protective plate having a medium sliding width previously processed into a predetermined shape by etching as a mask during etching, the self-alignment function is exerted, and the disadvantage that the sliding width of both is displaced can be avoided. It becomes possible to do.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method of manufacturing a thin film magnetic head according to the present invention will be described in detail below with reference to the accompanying drawings. 1 is a plan view showing a manufacturing process of the thin film magnetic head of the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a sectional view taken along the life dimension line in FIG. It is a figure which shows the cut surface of. The same parts as those of the magnetic head described above are designated by the same reference numerals.

In the figure, reference numeral 1 denotes a substrate made of a semiconductor wafer, glass or the like, on which a magnetic film is formed by repeating film formation, etching and polishing operations by fine processing using a well-known photolithography technique. Lower core 2 consisting of
The coil 4 insulated by the insulating material 3A, the upper core 5 made of a magnetic film, the magnetic gap 6 between the upper and lower cores, and the insulating material 3B covering the whole are provided to form a magnetic circuit. As the magnetic film, for example, FeAlSi, FeN or the like can be used. The magnetic circuit forming process is the same as the conventional head manufacturing method. The upper insulating layer 3B may or may not be provided, and the illustration thereof is omitted in FIG. 1 to clarify the internal structure.

A large number, for example, several thousand, of such thin film magnetic head bodies 10 are arranged in order on the substrate 1, but in FIG. 1, two are shown as a representative.
When the normal magnetic circuit forming process is completed in this way, the medium sliding width processing is performed by using the photolithography technique without cutting each head chip. In this processing, as shown in FIG. 1, processing holes 11 are formed on both sides of the upper and lower cores by etching, leaving a portion corresponding to the medium sliding width W around the upper and lower cores. This processing hole 11
Is provided so as to penetrate the substrate 1, and the medium sliding width W
Are made uniform in the length direction of the core (vertical direction in FIG. 1). This width W is typically 1
It is around 00 μm.

For example, a photoresist can be used as a mask for this etching operation, and an ion beam method, a sand blast method, a wet or dry etching method can be used as a method for penetrating the processed hole 11. . When the medium sliding width processing is completed in this way, a protective substrate (not shown) processed in the same way is attached from both sides using a glass bonding method or the like, and the vicinity of the core tip is not connected. The final head shape is obtained by performing processing similar to the conventional one such as exposing the tip of the core by cutting along the life dimension line passing through. As described above, since the medium sliding width processing is performed on the substrate by using the etching processing which is excellent in processing accuracy, not only the sliding width W of a large number of heads can be accurately defined at one time, but also Machining hole 11
Since the coil 4 and the coil 4 do not cross each other, it is possible to prevent the coil from breaking.

Further, since the working precision is high, the medium sliding width W becomes constant, and the width W does not change even if the life dimension line 12 fluctuates in the coil direction, so that a stable tape touch or the like can always be obtained. it can. By the way, as described above, the medium sliding width W is very small, around 100 μm, whereas the thickness of the substrate 1 needs to be strong enough to withstand the above-mentioned process, and therefore at least about 1 mm. Is needed. Then, when the above-mentioned etching method is used to grind a substrate having a thickness of 1 mm, the ion beam method and the sandblast method require a considerable amount of time for etching, and the photoresist is used as a mask. Has a small selection ratio for resist and substrate, so its thickness is 1mm.
It may be difficult to grind the substrate. Furthermore, in wet or dry etching, since the etching shape becomes tapered, accuracy may deteriorate, and it may be difficult to obtain high accuracy.

Therefore, the second to fourth embodiments described below can be adopted. The second embodiment has the same basic shape as that of the first embodiment shown in FIG.
As the substrate, a normal wafer or glass is not used, but a photosensitive material, such as a photosensitive glass substrate, which changes its crystal structure by being exposed to light, for example, ultraviolet rays, is used. When the photosensitive glass substrate is used in this way, it also reacts with ultraviolet light exposure during the magnetic circuit forming process. Therefore, in order to prevent this, as shown in FIG.
Reflective films 14A and 14B that reflect, for example, ultraviolet light, which is an exposure light, are formed on the surface, preferably the front surface and the back surface.
Such a reflective film 14 can be formed of, for example, chromium (Cr) or aluminum (Al).

If a magnetic circuit is formed by using the substrate 1 having such a reflection film and performing the magnetic circuit forming process as in the first embodiment, the surface side, that is, the magnetic circuit is formed. A patterning process similar to the shape of the processed hole 11 shown in FIG. 1 is applied to the reflection film 14A on the surface side by using, for example, a photolithography technique, and the reflection film in this portion is removed. After the reflection film is removed, it is exposed to, for example, ultraviolet rays to expose the portion corresponding to the processed hole 11, and then the exposed portion is crystallized by heat treatment at a temperature of about 600 ° C. Then, by subjecting this to an acid treatment such as hydrofluoric acid, it is possible to dissolve only the photosensitive portion and to obtain the same shape as shown in FIG. Photofoam glass (trade name) can be used as such a photosensitive glass substrate.

By using the substrate 1 made of a photosensitive material as described above, the etching processing of the processing hole 11 can be easily performed while maintaining high dimensional accuracy. In this case, if the protective substrate is adhered prior to the crystallization heat treatment of the photosensitive portion, heat of about 600 ° C. during the crystallization heat treatment causes annealing of the magnetic film and welding of the protection substrate at the same time. Therefore, the manufacturing process can be further shortened, and the cost can be further reduced accordingly. A third embodiment for facilitating the etching of the processed hole 11 is shown in FIGS. That is, in the substrate 1, from the back surface side to the front surface side (the surface where the magnetic circuit is to be formed), the etching promoting hole 1 is previously formed at a position substantially corresponding to the processed hole 11 to be formed.
5 is formed by etching or the like using a photolithography technique. In this case, this etching promotion hole 15
Since there is a possibility that a problem may occur in advancing the magnetic circuit formation process if it penetrates to the surface, it is not penetrated, but is left with a thickness of, for example, several tens of μm.

Thus, the substrate 1 with the etching promoting holes
A magnetic circuit forming process is performed in the same manner as the magnetic circuit in the same manner as in the first embodiment, and thereafter, a medium sliding width process is performed by etching to perform the etching promoting hole 1
5 is penetrated to the surface side. In this case, only a few 10μ
Since the processed hole 11 can be formed with an etching amount of about m, it can be easily processed by the ion beam method, the sandblast method, the wet method or the dry etching method described above, and the same high accuracy as in the case of the first embodiment. The medium sliding width can be processed with.

Further, as a method of forming the substrate 1 having the etching promoting hole, in addition to the method of forming the promoting hole 15 from the back surface of the substrate 1 in advance as described above, a penetrating etching promoting hole is formed. A method of forming a substrate having an etching promotion hole by bonding a substrate and a substrate having a thickness of several 10 μm, or bonding a substrate having the etching promotion hole formed therethrough and a substrate having a thickness of 100 μm or more It is possible to employ a method of forming a substrate with an etching-promoting hole in which the entire substrate having a lever thickness of 100 μm or more is polished so that the remaining amount is about several tens of μm.

According to the third embodiment, since the processing hole is formed in advance in the state where nothing is formed on the substrate, it is not necessary to consider the processing damage to the magnetic head portion,
Holes can be easily processed. Therefore, the substrate 1 is not limited to a semiconductor wafer, glass, a photosensitive substrate, or the like, and a ceramic substrate having excellent wear resistance may be used to form the etching promoting hole 15 by various methods such as laser processing. .

Next, a fourth embodiment for facilitating the etching of the processed hole 11 will be described with reference to FIGS. 7 and 8. The fourth embodiment is an improvement of the third embodiment, and the substrate 1 with the etching promoting holes 15 is provided.
1 is used. In the first to third embodiments, a photoresist is generally used as a mask for etching the substrate, but in this embodiment, the protective substrate 16 is used.
Then, the medium sliding width processing is performed in advance, leaving a portion corresponding to the medium sliding width W, and this is used as a mask. The situation at this time is shown as an enlarged view in FIG. 8, and FIG.
FIG. 3 is a cross-sectional view taken along the line III-III in the drawing, showing an enlarged cross-sectional view of the core tip portion before etching, and FIG. 8B shows an enlarged cross-sectional view of the core tip portion after etching. The broken line in FIG. 8A indicates the progress of substrate etching.

By performing the medium sliding width processing by etching in this manner, it is possible to ensure the same processing accuracy as that of the first embodiment, and the same processing promoting effect as that of the third embodiment. Can also be demonstrated. Also, in this case,
Since the protective substrate 16 does not have a head pattern, the sliding width machining for the protective substrate 16 can be performed at high speed and in large quantity by machining, and the mass productivity can be improved accordingly. Furthermore, since etching is performed using the protective substrate 16 as a mask, the self-alignment function can be exhibited, and the problem that the sliding width is displaced between the protective substrate 16 and the head pattern forming substrate 1 can be eliminated. Becomes

As described above, in this embodiment, the medium sliding width is machined by etching rather than by machining, so that the machining accuracy is improved, and therefore, problems such as coil breakage are not caused. And it can be mass-produced at one time. The structure of the thin film magnetic head is not limited to that shown in the present embodiment, and the method of the present invention can be applied when manufacturing a thin film magnetic head having another structure.

[0026]

As described above, according to the method of manufacturing the thin film magnetic head of the present invention, the following excellent operational effects can be exhibited. Since the medium sliding width is processed by etching instead of machining,
It is possible to maintain high processing accuracy and quickly perform a large amount of processing at one time. Therefore, since the processing accuracy is high, it is possible to prevent the occurrence of coil breakage and the like, and it is possible to improve the yield. Further, by forming the etching promoting hole in the substrate in advance, the medium sliding width processing by etching can be performed quickly, and further the processing efficiency can be improved.

Furthermore, by using a protective substrate which has been previously subjected to the medium sliding width processing as a mask during the medium sliding width processing, the self-alignment function can be exerted and the processing accuracy can be further improved. Further, by using the substrate made of a photosensitive material, it is possible to quickly perform etching when processing the medium sliding width.

[Brief description of drawings]

FIG. 1 is a plan view showing a process of manufacturing a thin film magnetic head of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a view showing a cut surface when cut along a life dimension line in FIG.

FIG. 4 is a cross-sectional view showing a head using a substrate with a reflective film for explaining a second embodiment of the present invention.

FIG. 5 is an enlarged cross-sectional view showing a head using a substrate with etching promotion holes for explaining a third embodiment of the present invention.

6 is a perspective view at the time of manufacturing the head shown in FIG.

FIG. 7 is a perspective view at the time of manufacturing a head for explaining a fourth embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view showing a head tip portion during etching according to a fourth embodiment.

FIG. 9 is a plan view showing a general thin film magnetic head.

10 is a cross-sectional view taken along the line I-I in FIG.

11 is a side view showing a medium sliding surface that is the head tip portion of FIG.

FIG. 12 is a diagram showing a thin film magnetic head provided with a protective substrate.

FIG. 13 is a diagram showing another type of magnetic head provided with a protective substrate.

FIG. 14 is an enlarged view showing a thin film magnetic head provided with a protective substrate.

[Explanation of symbols]

1 ... Substrate, 2 ... Lower core, 3A, 3B ... Insulating material, 4 ... Coil, 5 ... Upper core, 6 ... Magnetic gap, 8 ... Medium sliding surface,
11 ... Machining hole, 12 ... Life size line, 14A, 14B ... Reflective film, 15 ... Etching promoting hole, 16 ... Protective substrate, W ...
Medium sliding width.

Claims (4)

[Claims] 1. A method of manufacturing a thin film magnetic head, which comprises: performing a predetermined magnetic circuit forming process on a substrate to form at least a lower core, a magnetic gap, a coil, and an upper core; and etching the substrate. A method of manufacturing a thin-film magnetic head, characterized in that it comprises a step of performing a medium sliding width process by leaving a portion corresponding to the medium sliding width by applying. 2. The substrate is pre-formed with an etching-promoting hole having a predetermined shape from the back side opposite to the surface on which the magnetic circuit forming process is performed to just before the surface,
2. The method of manufacturing a thin film magnetic head according to claim 1, wherein the etching promoting hole is penetrated by performing the etching process from the front surface side of the substrate. 3. After performing the magnetic circuit forming process, a protective substrate which has been subjected to a medium sliding width process in advance is provided on the substrate, and the substrate is subjected to the etching process using the protective substrate as a mask. The method of manufacturing a thin film magnetic head according to claim 1, wherein the thin film magnetic head is constructed. 4. A method of manufacturing a thin film magnetic head, comprising the steps of forming a reflective film in advance on the surface of a substrate made of a photosensitive material, and performing a predetermined magnetic circuit forming process on this substrate to at least the lower core and the magnetic gap. A step of forming a coil and an upper core, and a step of partially removing the reflective film by forming a pattern having a desired shape on the reflective film,
Manufacturing a thin film magnetic head, characterized in that it comprises a step of exposing a portion of the substrate from which the reflective film is removed to light and performing an etching process into a predetermined shape to perform a medium sliding width process. Method.