JPH011113A - Manufacturing method of thin film magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a magnetoresistive system that applies a signal magnetic field to a magnetic thin film having -axis magnetic anisotropy and detects it as a change in electrical resistance in the direction of the easy axis of magnetization. The present invention relates to a thin film magnetic head (hereinafter referred to as a thin film MR head) that includes an effect element (hereinafter referred to as an MR element) and detects a signal recorded on a magnetic recording medium.

<Prior Art> It has been known that thin film MR heads have many advantages over wire-wound magnetic heads.

This thin film MR head changes the magnetization direction inside the MR element by receiving a signal magnetic field written on a magnetic recording medium such as a magnetic tape, and the MR head responds to the change in the magnetization direction.
The change in internal resistance of the element is extracted as an external output. Therefore, the M14M R head is a magnetic flux responsive head and can reproduce a signal magnetic field without depending on the transport speed of the magnetic recording medium.

In addition, this thin-film MR head can be easily fabricated with high integration and multi-element technology by applying semiconductor microfabrication technology, so it is seen as a promising magnetic head for playback in fixed-head PCM recorders that perform density-controlled recording. has been done.

Since such an MR element has a sensitivity characteristic that exhibits a square change with respect to an external magnetic field, a predetermined bias magnetic field is required when the MR element is configured as a read head. Methods of applying this bias magnetic field include a method of inducing a bias magnetic field by flowing a direct current through a conductor, and a method of inducing a bias magnetic field by flowing a direct current through a conductor, and a method of inducing a bias magnetic field by flowing a direct current through a conductor.
A method is known in which a bias magnetic field is applied using a high coercive force thin film such as a magnetic layer.

On the other hand, the M
A yoke-type MR head (hereinafter referred to as a YMR head) in which the R element is separated from the head tip and a magnetic flux introducing path (yoke) is arranged to guide the magnetic flux generated in the magnetic recording medium to the MR head.
It is known that a thin-film magnetic head called .

The third method for manufacturing the MR element part of the conventional YMR head
It is shown in FIG. However, FIG. 4 shows the structure taken along the line A-B in FIG. 3.

A ferromagnetic thin film 5 (N1-Fe alloy film), which will become an MR element, is formed on a substrate 1 by a vapor deposition method or the like, and is processed into a desired shape as shown in FIG.

Since the MR element has a multi-track configuration, the track width of the MR element is usually set to about 50 to 200 .mu.m.

When the track width of the MR element becomes smaller, the magnetic domain state changes irreversibly, making Barkhausen noise more likely to occur in the ΔR/R characteristics. Therefore, as shown in the same figure (bl), a high coercive force thin film 7Co-P is attached to both ends of the ferromagnetic thin film 5.
It is necessary to provide an MR element without Barkhausen noise by applying a weak magnetic field in the easy axis direction to eliminate the domain walls. Note that the high coercive force thin film 7 mentioned above is created by electroless plating.

Further, after the ferromagnetic thin film 5 is formed, a conductive layer 8 which will become a lead part is formed by vapor deposition or RF sputtering of Al, A6-Cu, etc., and is chemically etched to form a head etc. as shown in the same figure (C1). It is processed into the desired shape.

<Problems to be Solved by the Invention> In the manufacturing process of the above YMR head, the high coercive force thin film 7
The pre-treatment conditions and plating conditions for electroless plating for creating an electroless plating film become stricter as the area to be plated becomes smaller. Therefore, as the track width of the MR element becomes smaller, the deposited area becomes smaller, and the reproducibility of the high coercive force thin film produced by electroless plating is poor.

That is, if the plating pretreatment conditions are made stricter, the ferromagnetic thin film forming the MR element is very thin, 200 to 500λ, and will be corroded by the pretreatment liquid. Furthermore, if the conditions are such that plating is likely to occur, there is a problem in that the characteristics of the high coercive force thin film deteriorate.

Further, in the step of connecting the lead portion 8 of the ferromagnetic thin film 5C, the surface of the ferromagnetic thin film that will become the MR element is exposed to the lead etching solution and the resist stripping solution. Therefore, since the ferromagnetic thin film is very thin at 200 to 500 A, there is a problem in that the characteristics of the thin film MR element deteriorate if the surface of the ferromagnetic thin film is oxidized or the like.

The purpose of the present invention is to improve the reproducibility of electroless plating of high coercive force thin films related to MR elements used in thin film magnetic heads, and to prevent the surface of ferromagnetic thin films from oxidation, thereby improving the characteristics of thin film MR elements. shall be.

<Means for solving the problem> A ferromagnetic thin film serving as the MR element and an upper insulating layer SiO of the MR element are sequentially laminated, and the two layers of the above ferromagnetic thin film and the upper insulating layer SiO are simultaneously formed. After processing, the upper insulating layer SiO covering the ferromagnetic thin film of the lead portion is etched, and a high coercive force thin film and a conductive layer are sequentially laminated.

<Example> FIG. 1 shows a planar configuration of a YMR head according to an example of the present invention. FIG. 2 (al shows the structure of the cross section A-B in FIG. 1, and FIG. 2 bl shows the structure of the C-Dlr plane of FIG. 1.

The substrate 11 forming the lower yoke is made of N i -Zn ferrite or M n -Zn ferrite. 5i02. on this board ll. A first insulating layer 2 made of Si3N4 or the like is formed by RF sputtering, P-CVD, or the like. Next, on this first insulating layer 2, M o +Cu, A#
Alternatively, the conductor layer 3 made of A11-Cu alloy film or the like is R
It is formed by F sputtering method, vapor deposition method, etc. In order to process this conductor layer 3 into the shape of a bias layer, a chemical etching method, a sputter etching method, etc. are used. To explain with a specific example, in the case of chemical etching method, C
The u film is made of nitric acid (H'N03) ammonium decaprosulfate ((N
H3)2S208) Raw water (H2O), A6 and Ae-C
The u membrane consists of potassium hydroxide (KOH) ammonium tenpersulfate ((N)13)2S20ρ + water (HO) or phosphoric acid (H
3P04) Deca-nitric acid (HNO3) + acetic acid (CHC00H)
Elachinda liquid, which is raw water (H2O), may be used. In the case of sputter etching method 1M o , A l , C
Films such as u can be processed by a known method by introducing Ar gas.

S is deposited on the conductor layer 3 formed as described above by vapor deposition or the like.
A second insulating layer 4 made of iO is formed.

Since the SiO film 4 has excellent surface smoothness and film quality, the ferromagnetic thin film 1'Ji-Fe alloy film 5, which will become the MR element to be laminated next, has good magnetic properties. A third insulating layer 5i06 made of SiO is formed on the Ni-Fe alloy film 5.

Here, peralloy (Ni
-Fe alloy film) The characteristics of the film will be described below.

After forming a Si0 layer with a thickness of about 40 OA on a glass substrate by vapor deposition, a Ni-Fe alloy film with a thickness of about 320λ is formed by vapor deposition in a magnetic field, and a thick Si0 layer is formed on the Ni-Fe alloy film. A sample with approximately 40 OA of SiO formed was heated at 200°C in a magnetic field.
Table 1 shows the changes in magnetic properties during 2-hour vacuum annealing. For comparison, a case where C3iO3 is formed on the upper and lower sides of the Ni--Fe alloy film is also shown. The magnetostriction constant λ5 is Ni
Since it is extremely sensitive to the composition of the -Fe alloy film, it is suitable for detecting compositional changes due to diffusion between the Ni-Fe alloy film and the underlying layer.

As can be seen from Table 1, when Si0 layers are formed above and below the Ni-Fe alloy film, the change in λ5 is small and diffusion is prevented.

Regarding the two layers of the ferromagnetic thin film 5 and the third insulating layer Si, 06 formed under the above conditions, the MR element part a shown in FIG.
And the lead portions b and c of the MR element are processed into appropriate shapes by sputter etching or ion milling. Ar gas may be used as the introduced gas.

Next, leaving the third insulating layer 6 covering the MR element a, the outer lead b
, c is etched by an RIE (reactive ion etching) method. CF4 (Freon 14), CF4 as introduced gas
+H2 and CF4+H2 may be used. A Co--P7 layer is formed by electroless plating on the ferromagnetic thin film of the leads b and c in which SiO has been etched by the above RIE method.

Since the surface of the Co-P 7 layer plated by the electroless plating method covers almost the entire area of leads b and c, it can be made about 300 to 1000 times larger than the conventional one, and can be produced with good reproducibility.

Next, a conductive layer of Al or A is applied to the lead portions of the MR element.
11- Cu %if etc. 8 is prepared by vapor deposition or RF sputtering, and molded by chemical etching or dry etching.

When creating an MR element through the above steps, the main body of the MR element a is covered with the third insulating layer SiO, so it is not exposed to the etching solution and the resist stripping solution, so that the surface of the ferromagnetic thin film 5 is No oxidation and no deterioration of magnetic properties.

Further, since the contact area between the MR element a part and the leads b and c is large, contact resistance can also be ignored.

Next, the first part that covers the front cast part d. After etching the second and third insulating layers, a new insulating layer 9, which will become the GaP section, is formed by RF sputtering and P-CVD as shown in FIG. 2+a+. Similar to the manufacturing process of conventional YMR heads, after etching the insulating layer at the connecting portion of the upper yoke part 10 and lower yoke part 11 using the RIE method, the upper yoke ↓
A YMR head is completed by creating a N i -Fe alloy film that has a value of 0.

In the above embodiments, the YMR head was explained, but it is clear that the present invention can have similar effects even when applied to other MR heads such as non-shielded MR heads and double-sided shielded MR heads. be.

<Effects of the Invention> As detailed above, by using the present invention, a high coercive force thin film with good magnetic properties constituting the MR element portion can be formed with good reproducibility, and the surface oxidation of the ferromagnetic thin film can be prevented. Since the process can be carried out without any problems, an MR head with good characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a plan view of one embodiment of the present invention, and FIG. 2 (al.
is a sectional view taken along line A-B in Figure 1, and Figure 2 is a cross-sectional view taken along line C-B in Figure 1.
3 is a plan view of a conventional thin film MR head, and FIG. 4 is a sectional view of the same head. 2.9... Insulating layer, 3.8... Conductor layer, 4,6...
SiO insulating film, 5... ferromagnetic thin film, 7... high coercive force thin film, 10... upper yoke, 11... lower yoke. Agent: Patent Attorney Takeshi Sugiyama (and 1 other person)
・: // Lower surface 3-ri's 2 5 pieces tσ) 1/T mark 3-ri's 2 Nada (b) Fig. 3 Fig. 4

Claims (1)

[Claims] 1. In a method for manufacturing a magnetoresistive thin film magnetic head that detects changes in an applied signal magnetic field as changes in electrical resistance of a ferromagnetic thin film having uniaxial magnetic anisotropy, an insulating layer of Si
O, a ferromagnetic thin film, and an insulating layer SiO are sequentially laminated, and after simultaneous processing of the above two layers, the ferromagnetic thin film and the insulating layer SiO, the insulating layer SiO on the ferromagnetic thin film is etched to form a high coercive force thin film and a conductive layer. A method for manufacturing a thin film magnetic head characterized by sequentially laminating layers.