JPS60173891A - Formation of magnetoresistance effect type thin film - Google Patents

Abstract

PURPOSE:To enable the formation of thin film patterns of submicron order width by a method wherein a lift-off mask is formed on a substrate, and then a magnetic thin film is formed over the entire surface; further, this thin film is etched by oblique incidence of ion beams by using the lift-off mask as a shadow mask. CONSTITUTION:The lift-off mask 11 made of organic resist or the like having an aperture 11a at the part of MR element film formation is formed on the substrate 10 made of non magnetic material. Next, an Ni-Fe film 12 for preparation of an MR element film is formed on the exposed part of this substrate 10 and on the lift-off mask 11. Then, the film 12 is etched by shadow by obliquely irradiating the normal A of the substrate 10 with Ar ions beams 13 from the direction of an angle thetaT. Thereby, the film 12 remains only at the part corresponding to the shadow of the side wall 11b of the mask 11 without being etched, and the other part is completely removed by etching. Finally, the MR element film 14 having a submicron order width is formed by patterning on the substrate 10 by removing this mask 11 with flux.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for forming a magnetoresistive groove film, and particularly to a method for forming a fine pattern thereof.

[Prior art]

Figure 1 shows a magnetoresistive thin film head (hereinafter referred to as MR) that can be formed using a magnetoresistive thin film pattern.
,μ禾♀す7-、)1/i'i9 1000A MTI η11μn It is an enlarged configuration diagram of the main part showing the positional relationship with the dead deer body. In the figure, 1 is an MR element having a substantially rectangular parallelepiped shape, and 2 is a magnetic recording medium (2) made of a magnetic material.
(hereinafter referred to as a recording medium), 3 is a magnetization transition region in the recording medium 2, and this recording medium 2 is assumed to move in the X direction in the figure. .

In such a configuration, leakage magnetic flux is generated from the magnetization transition region 3 on the recording medium 2, and this leakage magnetic flux spreads over the space on the recording medium 2 and is absorbed by the adjacent magnetization transition region.

When the MR element 1 is placed in this space, the magnetization vector existing in the YZ plane of the MR element 1 is sensitive to this leakage magnetic flux, and the direction of the magnetization vector changes within the YZ plane. At this time, if a constant radio wave is passed in the Z direction of the MR element 1 and the angle between this current vector and the magnetization vector is θ, then the two-way specific resistance within the MR element 1 can be expressed by the following equation.

ρ=ρ. +Δρ・cos 2θ (1) However, ρ. is the specific resistance that does not depend on the direction change of the magnetization vector,
Δρ·CO32θ is a resistivity that depends on the direction change of the magnetization vector.

At this time, the length of the MR element 1 is t, and the cross-sectional area is S.

Assuming that the constant current in the Z direction is 1, the voltage E generated across the MR element 1 is given by the following equation.

E-(ρ.+Δρ'cos”θ)(z/s)-■-Mountain(
2) Therefore, the output of the MR head can be extracted as a voltage change corresponding to the angular change in the magnetization vector within the MR element 1.

In order to improve the reproducing resolution of the MR head constructed in this way, it is sufficient to faithfully change the magnetization vector within the MR element 1 in accordance with the leakage magnetic flux accompanying the magnetization transition. For this purpose, it is necessary to reduce the floating material between the MR element 1 and the recording medium 2, and at the same time to reduce the width of the MR element 1 in the Y direction. -Also, track direction (Z direction)
In order to increase the recording density, it is desirable that the length of the MR element 1 (in the Z direction) be approximately 10 μm or less. In addition, in order to facilitate control of the magnetic domain structure present in the radial element 1 and increase the output voltage for signal reproduction, it is necessary to increase the aspect ratio defined by the following equation.

Aspect ratio - (length 'g of MR element 1/width of MRJ element 1) From the above explanation, in order to realize high-density signal reproduction using an MR head in which the MR element 1 has a magnetic flux sensitive sensor length, the MR It is necessary that the width of the element 1 is 1 to 2 μm or less.

However, when realizing a pattern width of about 1 μm using conventional photolithography techniques, there are often disadvantages such as exposure device failure and a decrease in production yield.

[Summary of the invention]

Therefore, the present invention has been made to eliminate the above-mentioned conventional drawbacks, and its purpose is to improve the MR
After forming the device pattern by the lift-off method, the lift-off mask is used as a reverse mask and an ion beam is incident from an oblique direction for etching. This makes it possible to form a thin film pattern with a submicron width. The object of the present invention is to provide a forming method. Embodiments of the present invention will be described in detail below with reference to the drawings.

[Embodiments of the invention]

FIGS. 2(a) to 2(e) are cross-sectional process diagrams of essential parts for explaining an example in which the method for forming a magnetoresistive thin film according to the present invention is applied to a method for forming an MR head. In the same figure,
As shown in FIG. 5A, a lift-off mask made of, for example, an AZ-based organic resist or the like having an opening 11a at the MR element film forming area is placed on a substrate 10 made of a non-magnetic material such as Mn-2n. 11 is formed to have a thickness of about 2 μm. Next, as shown in FIG. 2B, an N1-F8 film 12 for forming an MR element film is formed to a thickness of about 50 OA on the exposed portion 2 of the substrate 10 and the lift-off mask 11 by vacuum evaporation or sputtering. do. In this case, the MR element width is approximately jOl1m'''C.Next, as shown in the same figure (C), the normal A of the substrate 10 is
Angle θ with respect to. This Ni-F is obliquely irradiated with an Ar ion beam 13 with an intensity of about 0.5 KeV g from the direction of
The e-film 12 can be shadow etched. by this,
As shown in FIG. 3D, the N, -Fe film 12 remains unetched only in the portion corresponding to the shadow of the side wall 11b of the lift-off mask 11, and is completely etched away in the other portions. Next, by removing the lift-off mask 11 on the substrate 10 using a solvent, a pattern of the MR transponder film 14 with a submicron width is formed on the substrate 10, as shown in FIG. It is formed.

According to such a method, the MR element film 14 having a submicron width determined by the height of the lift-off mask 11 and the incident angle OT of the ion beam 13 can be easily formed. Here, as described above, the height of the lift-off mask 11 is 2 μm.

N1-F for MR element formation, the film thickness of the film 12 was 5 [H)A.

In addition, the intensity of the Ar ion etching beam 13 was set to 0.5.
Incident angle θ of the etching beam 13 as K e V
1, the incident angle θ is changed as shown by the dotted curve I in FIG. As the pattern width is reduced, the MR element H14 can be obtained with a smaller pattern width. In addition, the curve ■ shown by a solid line in FIG. 3 is a calculated value for confirming the actually measured value of the curve ■. 7): In this embodiment, the incident angle θT of the etching beam 13 is set to about 3
By setting the angle to 0 degrees or less, it was possible to obtain the MR element film 14 with a submicron width of approximately 1 μm.

According to such a method, the MR element film 14 can be easily formed with a submicron pattern width, so that an MR head for high-density recording/reproduction can be manufactured with good yield.

In the above-described embodiments, the case where the magnetoresistive thin film is applied to the formation of an element pattern of an MR head has been described, but the present invention is not limited thereto, and can be applied to, for example, a magnetic bubble memory element, etc. It goes without saying that the same effects as described above can be obtained even when applied to the formation of submicron width patterns for thin film devices.

[Effect of the Invention J As explained above, according to the present invention, after a lift-off mask is formed on a substrate, a magnetic thin film is formed on the entire surface, and an ion beam is obliquely directed onto this magnetic thin film using the lift-off mask as a shadow mask. By etching with incident light from the same direction, it is possible to easily form a magnetic film pattern with a submicron width, which eliminates the need for conventional exposure equipment and greatly improves production yields. The effect is (if).

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the arrangement relationship between an MR head and a storage medium, and FIGS. FIG. 3 is a diagram showing the relationship between the pattern width and the incident angle θT of the ion beam. 1... Magnetoresistive thin film element (MR element), 2.
. . . Magnetic recording medium (recording medium), 3 . . . Magnetization transition region, 10 . . . Substrate, 11 . . . Lift-off mask, 11a . . .・Side wall,
12... Ne-Fe film, 13... ion beam, 14... fvIR element! . Figure 1

Claims (1)

[Claims] A lift-off mask is formed on a non-magnetic substrate, and a magnetic thin film is formed at least in the opening of the lift-off mask on the non-magnetic substrate, and then an ion beam is incident from an oblique direction using the lift-off mask as a shadow mask to form the magnetic thin film. A method for forming a magnetoresistive groove film that includes etching to form a pattern.