JPH03232109A - Production of thin-film magnetic head - Google Patents

Abstract

PURPOSE:To form upper and lower magnetic material layer patterns which have a rectangular section even at a narrow track width and to obviate the remaining of etching in the corner parts by removing a mask pattern after the completion of the 2nd ion-etching to remove the resticking layers generated on side walls by a 1st ion etching stage for removing unnecessary regions. CONSTITUTION:The upper magnetic material layer 18 and lower magnetic material layer 13 formed on a substrate 10 consist of NiFe films formed by a sputtering method. An insulating layer 14 to form a gap is constituted of a silicon oxide film. The photoresist patterns 21 equal to the prescribed track width W are then formed. The resticking layers 20 are formed on both side walls of the upper and lower magnetic material layers 18, 13 and the photoresist patterns 21 when the 1st etching to remove the unnecessary magnetic materials is executed by an Ar beam. A substrate holder is rotated backward in succession thereto and the etching to remove the remaining side of the resticking layers 20 is executed. Finally, the photoresist patterns 21 are stripped and the thin-film magnetic head subjected to pole trimming is completed. The pole trimming which has the rectangular section and is free from the remaining of the etching is attached in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film magnetic head used in magnetic disk devices, magnetic tape devices, etc., and particularly to a method for forming upper and lower magnetic layer patterns.

[Prior Art] In recent years, in the field of magnetic recording, recording densities have been increasing, and magnetic heads that support magnetic recording as well as recording media are manufactured using integrated thin-film magnetic head technology instead of conventional ferrite heads. Inductive thin film magnetic heads have been put into practical use. This thin-film magnetic head has much better frequency characteristics than ferrite heads, and because a manufacturing process based on semiconductor technology is applied, it is possible to manufacture high-precision, high-density magnetic heads at low cost. This is possible and is becoming the mainstream of magnetic heads in the future.

FIGS. 6 and 7 are a schematic perspective view and a sectional view showing the structure of a part of the transducer of such a thin film magnetic henodic.

Note that FIG. 7 corresponds to the AA cross section in FIG. 6. The structure of the thin film magnet will be described below with reference to FIGS. 6 and 7. In FIG. 7, AI! , 203, etc., are formed by a sputtering method or the like. Next, NiFe
A lower magnetic layer 13 made of a soft magnetic material such as an alloy or a CO metal-based amorphous material (for example, CoZrNb) is formed. After that, an insulating layer 1 having a thickness equal to a predetermined gap length is formed.
4 is formed. Next, an organic layer 15 which becomes a step eliminating layer for the lower magnetic layer 13 is formed, and a coil 16 made of a conductive material is formed. Thereafter, the organic layer 17, which becomes the step eliminating layer of the coil 16, is formed again. Next, NiF
e alloys and C〇-metallic amorphous materials (e.g. CoZrNb
), an upper magnetic layer 18 made of a soft magnetic material such as
A protective film (not shown) made of an insulator is formed to form a part of the transducer of the thin film magnetic head.

In recent years, the trend toward higher recording densities in magnetic storage devices has become more and more remarkable, and the track width (indicated by W in Figure 6) has become larger than ever in magnetic heads, which support magnetic recording technology as well as magnetic recording media. A narrow one is required. For this purpose, a thin film magnetic head as shown in FIG. 8, that is, a thin film magnetic head having a track width W' larger than a predetermined trunk width W, is prepared in advance, and finally the upper and lower magnetic layers are Tip of pattern (side facing medium)
Ion-etch the unnecessary parts of the image to remove them.
This series of steps is called pole trim), and a thin film magnetic head that achieves a predetermined track width W is being studied.

[Problems to be Solved by the Invention] By the way, the thin film magnetic gutter that has undergone ball trimming has the following problems.

That is, in the conventional pole trim process, the substrate holder of the processing/notching device that fixes the thin film magnetic head wafer is rotated, and an Ar beam is incident thereon from a substantially perpendicular direction to remove unnecessary upper and lower magnetic layers (e.g. NiFe film)
was being removed. However, this method has the problem that the rectangularity of the cross section of the pattern is lost and the track width cannot be precisely controlled.

FIGS. 9(a) and 9(t) are schematic diagrams of the upper and lower magnetic layers of the thin film magnetic head which have been bolt-trimmed by the conventional method described above, as viewed from the medium facing surface side. Here, (a) is a case where the track width is about 15 μm, and (2) is a case where the track width is about 5 μm. As is clear from FIG. 9, the ends of the upper and lower magnetic layer patterns are tapered, making it impossible to precisely define the track width.

In particular, in the case of a narrow track width (FIG. 9(b)), the cross section of the upper magnetic layer pattern is approximately triangular, and it is expected that the ability to write information to the recording medium itself is reduced. This is a problem not only because the trunk width cannot be strictly defined, but also for the magnetic head. Additionally, depending on the film thickness of the photoresist pattern that serves as a mask, there is also the problem that pars may occur due to redeposition.

On the other hand, as an ion etching method to realize a rectangular cross section,
Rotate the substrate holder to adjust the incident angle of the Ar beam to 40~
There is a method (oblique incidence method) in which ion etching is performed by setting the angle at 60 degrees. However, when this method is applied to the ball trim, there are the following problems. In other words, the region removed by the ball trim digs into the upper and lower magnetic layer patterns as shown in FIG.
5 and 17, the incidence frequency of the Ar beam that reaches the part of the corner indicated by the arrow B in Fig. 8 is extremely reduced, resulting in a problem that machining remains in the part of the corner. was there.

According to the inventor's study, the oblique incidence method (A
r pressure crab 2 Xl0-'Torr, acceleration voltage = 500
When pole trimming was carried out using the etching method (incidence angle = 45°), most of the trimmed area was removed in about 140 minutes, but some corners could not be completely removed even after continuing etching for more than 300 minutes. Ta. In addition, in the oblique incidence method, the first
As shown in FIG. 0, the etching rate of the photoresist increases by more than twice, whereas the etching rate of the NiFe film hardly increases. Therefore, it is necessary to further increase the thickness of the photoresist serving as a mask in response to the increase in the rate, which poses the problem of making it difficult to form a photoresist pattern.

The object of the present invention is to provide a method for manufacturing a thin film magnetic head that solves the above-mentioned problems, that is, to provide a pole trim in which the upper or lower magnetic layer pattern has a rectangular cross section even in a narrow track width, and there is no etching residue at a part of the corner. The purpose is to provide a method.

[Means to solve the problem]

The present invention provides a coil made of a conductive thin film between upper and lower magnetic layer patterns made of a soft magnetic thin film formed on a substrate, a magnetic gap layer made of a non-magnetic thin film, and electrical insulation and step elimination functions. A method for manufacturing a thin film magnetic head sandwiching an organic layer that performs the following steps: forming lower and upper magnetic layer patterns having track widths larger than a predetermined track width; A process of forming a mask pattern having a width approximately equal to a predetermined track width at the tip of the surface side, and changing the ion beam irradiation direction.
Etching is performed while fixed in a direction parallel to the longitudinal direction of the lower and upper magnetic layer patterns perpendicular to the track width direction,
a first ion etching step for removing unnecessary regions of the insulating layer forming the gap and the lower and upper magnetic layer patterns other than those covered by the mask pattern; A second ion etching process in which the left and right side walls of the upper magnetic layer pattern are irradiated with an ion beam simultaneously or on one side at a time to remove the redeposited layer formed on the side walls in the first ion etching process, and etching is completed. The method is characterized in that it includes a step of removing the mask pattern in this order.

In the present invention, in the first ion etching step, it is preferable that the angle θ between the incident beam and the normal to the wafer surface be at least 10 degrees.

[Effect]

According to the inventor's study, etching is carried out by fixing the wafer with respect to the direction of incidence of the ion beam and setting the angle θ of the ion beam to the normal to the wafer surface to be 10 degrees or more. When etching was performed, no redeposition or etching residue occurred on the side of the pattern perpendicular to the incident ion beam.

This will be explained in connection with the ball trim using FIG. 2. Figure 2 shows the transducer of a thin film magnetic head.
FIG. 3 is a plan view and a side view schematically showing the relationship between the wafer 30 formed with the ion beam and the incident angle of the ion beam. Here, the magnetic material pattern 19 corresponds to the lower magnetic layer 13 or the upper magnetic layer 18 in FIG. 6 or 7.

Also, in order to avoid complication of the diagram, one magnetic material pattern 1
Only 9 is enlarged and displayed. Further, the track width W' of the magnetic material pattern 19 before ion etching is formed to be larger than the predetermined track width W, as shown in FIG.

As shown by the arrow 31 in FIG. 2, the direction of incidence of the ion beam is fixed in the longitudinal direction of the track of the magnetic material pattern 19 (indicated by the broken line arrow 32), and the wafer is formed with a transducer of a thin film magnetic head. - When the angle θ between the normal 33 on the surface and the ion beam is set to 10 degrees or more and the ball trim, that is, the unnecessary magnetic material 34 shown with diagonal lines in FIG. No etching residue or re-deposition occurred on the side portion perpendicular to the direction of the incident beam (the portion indicated by diagonal line C in FIG. 2) among the portions that were etched.

Here, as the beam incidence angle θ increases,
The etching rate of the photoresist that serves as a mask increases (see Figure 10), and a thicker photoresist pattern is required, so this point must be kept in mind when setting θ. It is best to set it to a certain degree. Incidentally, the etching process described above will be referred to as the first etching process for convenience of the following explanation.

The above first etching process removes unnecessary magnetic material 34.
(The shaded area in Figure 2) is almost completely removed, but
A re-deposition layer was observed on the sides parallel to the beam incidence direction (indicated by arrows in FIG. 2). FIG. 3 is a schematic cross-sectional view of the magnetic pattern 19 in the track width direction after the first etching process, and it shows that re-deposition layers 20 are formed on both sides of the photoresist pattern 21 corresponding to a predetermined track width W. ing.

FIG. 4 is a graph showing the relationship between the angle β formed by the re-deposition layer 20 (see FIG. 3) and the film thickness of the photoresist pattern 21 (normalized by the film thickness of the portion to be pole trimmed). . Here, the circle mark indicates the case where etching was performed with the beam incident direction fixed in the longitudinal direction of the track, and the round mark indicates the case where etching was performed with the substrate rotated as usual. The material of the upper and lower magnetic layers 18.13 is Ni.
Fe, the insulating layer 14 is 5 iOz, and the etching conditions are Ar pressure crab 4 Xl0-'Torr, acceleration voltage: 5
It is 00V.

As is clear from FIG. 4, when etching is performed with the incident direction of the ion beam fixed in the track longitudinal direction of the magnetic pattern I9, the angle β between the re-deposition layer 20 and the wafer surface is smaller than that of the photoresist pattern 21. It has become clear that there is no correlation with the film thickness, that the angle is almost constant, and that it is approximately 90 degrees (8285 degrees).

Even when the substrate is rotated, the angle β increases as the photoresist film thickness increases, but only a value of 75 degrees or less is obtained.

Therefore, by removing the re-deposition layer 20 that occurs when etching is performed with the incident direction of the ion beam fixed, that is, without changing the angle β between the re-deposition layer 20 and the wafer surface, a nearly rectangular shape can be formed. A pole-trimmed magnetic material pattern having a cross section can be formed. The process of removing this re-deposition layer 20 (referred to as the second etching process) will be described below with reference to FIG.

In FIG. 5, the track longitudinal direction 32 of the thin film magnetic head wafer 30 that has undergone the first ion etching/notching process is +α (or -α) relative to the beam incident direction 31.
), the beam was irradiated at an angle of
0 is removed by etching one side at a time. At this time, the angle .theta. formed by the normal to the wafer surface and the incident beam may remain at the value .theta. set in the first etching step, and there is no need to change it. There is no particular limit to the value of the incident angle α of the beam in this second etching step, but the surface exposed when the re-deposition layer is over-etched is the side wall of the photoresist pattern 21, and the re-deposition layer 20 is mostly on the top. Alternatively, since the lower magnetic material layer is made of a magnetic material, it is desirable to set conditions such that the magnetic material and the photoresist are etched at the same speed. For example, if the magnetic material is N
In the case of iFe, as is clear from Fig. 10, α is set to 4.
The second etching step may be performed at an angle of 0 to 45 degrees.

By the method of manufacturing a thin film magnetic head as described above, the problems encountered with the conventional methods are solved, and a pole trim having a rectangular cross section and a narrow track width is realized.

[Example] An example of a method for manufacturing a thin film magnetic head according to the present invention will be described in order of steps with reference to FIG. Note that FIG. 1 is a schematic cross-sectional view in the track width direction.

As shown in FIG. 1(a), a thin film magnetic head transducer having a track width of W' was formed by a known thin film magnetic head manufacturing method. Here, the track width W' is 3
It is 0 μm. In addition, an upper magnetic layer 18 and a lower magnetic layer 13 (both have a thickness of 2.5 μm) are formed on the substrate 10.
m) is NiFe (Fe:
18 wt%) film, and the insulating layer 14 serving as a gap was composed of a silicon oxide film with a thickness of 0.3 μm. The conditions for forming the NiFe film and the silicon oxide film are Ar pressure 5 Xl0.
−3 Torr, input power density=7.5 W/cm2.

Next, as shown in FIG. 1(b), a photoresist pattern 21 (film thickness 25 μm) equal to a predetermined track width W (in this example, W = 3 μm) is formed, and unnecessary unnecessary parts are removed using an Ar beam. A first etching process was performed to remove the magnetic material. During etching with this Ar beam, the wafer is fixed so that the track longitudinal direction and the incident beam are approximately parallel, and the angle θ between the normal to the wafer surface and the incident beam is 25 degrees. I set it and etched it. The etching conditions are Ar pressure=
4×10-'Torr, acceleration voltage: 500V.

The state after the completion of the first etching step is shown in FIG. 1C, in which reattachment layers 20 are formed on both side walls of the upper and lower magnetic layers 18, 13 and the photoresist pattern 21. The angle between this re-deposition layer 20 and the wafer surface was about 85 degrees.

Thereafter, as shown in Figure 1(d), while maintaining the angle θ between the normal to the wafer surface and the incident beam at 25 degrees, the substrate holder is slightly rotated to align the longitudinal direction of the trunk and the beam. The angle formed by the incident direction of (corresponding to the angle α mentioned in the [Effect] section) is 40 degrees,
Etching was performed to remove one side of the re-deposition layer 20. Note that the etching conditions are the same as in the first etching.

Subsequently, as shown in Figure 1(e), while maintaining the angle θ between the normal to the wafer surface and the incident beam at 25 degrees, the substrate holder is rotated in the opposite direction, and the trunk is rotated in the longitudinal direction. Etching was performed to remove the remaining side of the re-deposition layer 20 while fixing the angle formed by the beam incident direction and the beam incidence direction to be 140 degrees as viewed from the track longitudinal direction. Note that the etching conditions are also the same as in the first etching step. Further, due to this etching, no change occurred because the Ar beam was hardly incident on the side wall where the redeposited layer removal etching was performed previously.

The above second etching process ((d) and (e) in Figure 1)
Figure 1) shows the state after completion.

Finally, the photoresist pattern 21 was peeled off to complete a thin film magnetic head with pole trim according to the present invention.

When a part of the transducer of the thin-film magnetic head pole-trimmed as described above was observed using an SEM, the track width was approximately 3 μm, and the cross-sections of the pole-trimmed upper and lower magnetic layers were approximately rectangular, with no sharp edges. I couldn't see either. Also, part of the corner (point indicated by arrow B in Figure 8)
No etching residue was observed at all, confirming that good pole trim had been performed.

In the above explanation, only an example was mentioned in which the second etching step for removing the redeposited layer is performed in two steps, but this is because a normal ion etching device uses only one ion gun.
This is because only one item is equipped. Therefore, multiple pieces (
If an ion etching device is equipped with at least two ion guns and has the ability to set the beam direction of each ion gun at ±40 degrees with respect to the longitudinal direction of the track when removing the redeposited layer, it is possible to eliminate The redeposition layer may be removed at the same time. In this case, there is an advantage that the working time required to remove the redeposited layer is half that of the present embodiment.

〔Effect of the invention〕

As described above, according to the present invention, a pole trim having a rectangular cross section and no etching residue is realized, and it is possible to manufacture a thin film magnetic head with a high track density that corresponds to the recent trend toward higher recording densities. becomes.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the present invention in the order of steps; Figs. 2 to 5 are diagrams for explaining the invention in detail; Figs. 6 and 7 are schematic diagrams of a thin-film magnetic head. A diagram showing the structure, Figure 8 is a diagram to explain pole trim, Figure 9 is a diagram to explain examples of problems with the conventional pole trim method, and Figure 10 is a diagram to explain the upper or lower magnetic layer. 3 is a graph showing the relationship between the etching rate of the NiFe film and the Ar beam incident angle. 10... Substrates 12, 14... Insulating layer 13... Lower magnetic layer 15, 17... Serving material layer 18... Upper magnetic layer 19...・Magnetic material pattern 20...Reattachment layer

Claims (1)

[Claims] (1) A coil made of a conductive thin film between upper and lower magnetic layer patterns made of a soft magnetic thin film formed on a substrate;
A method for manufacturing a thin film magnetic head comprising a magnetic gap layer made of a non-magnetic thin film and an organic material layer having electrical insulation properties and a step eliminating function, wherein a lower and upper magnetic head having a track width larger than a predetermined track width is provided. forming a mask pattern having a width approximately equal to a predetermined track width at least at the tip of the upper magnetic layer pattern on the medium facing surface side; Etching is performed fixedly in a direction parallel to the longitudinal direction of the lower and upper magnetic layer patterns perpendicular to the direction, and the insulating layer other than that covered by the mask pattern forming a gap and the lower and upper magnetic layer patterns are etched. a first ion etching step for removing unnecessary regions; irradiating the left and right side walls of the insulating layer and the lower and upper magnetic layer patterns from which the unnecessary regions have been removed simultaneously or on each side with an ion beam; A method for manufacturing a thin film magnetic head, comprising, in this order, a second ion etching step for removing the redeposited layer formed on the side wall by the ion etching step, and a step for removing the mask pattern after the etching is completed. .