JPS58176984A - Magneto-resistance device - Google Patents

Abstract

PURPOSE:To enhance yield through protection of magneto-resistance material from damage and also enhance reliability through improvement in moisture resistance by structuring a magneto-resistance material through formation of patterned ferromagnetic thin film on an insulated substrate and by forming a protecting film consisting of metal film. CONSTITUTION:A ferromagnetic thin film is formed through vacuum deposition of ferromagnetic material consisting of a Ni-Co alloy on the surface of insulated substrate 11, the specified magneto-resistance material 12 is formed by patterning such thin film with the etching method, and a metal film 13 consisting of Ta is vacuum deposited over the entire part. The area where will become electrode 14a, 15b at both ends of magneto-resistance material 12 is masked with a resist 15 and an anode oxide film 16. After removing the resist 15, electrodes 17a, 17b are formed by vacuum-depositing aluminium and thereby a magneto-resistance device is completed. A silicon oxide film, silicon nitride film or resin film 18 is coated thereon, a contact hole is formed by etching the electrodes 17a, 17b. Thereby, change of resistance for high temperature or high humidity and resistance changing rate can be extremely stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetoresistive device which has been modified to particularly improve the reliability of the magnetoresistive element.

Traditionally, magnetoresistive devices have been developed using N1-Co on an insulating substrate.
Basically, a ferromagnetic material such as 1-F or O alloy in a gold alloy is vacuum-deposited to form a ferromagnetic thin film, and this ferromagnetic thin film is etched into /4 turns to form a magnetoresistive element. configured.

That is, a magnetoresistive device is completed by forming electrode parts at both ends of this Δ-turn magnetoresistive element and forming an electrode metal layer on the electrode parts.

In this case, since the magnetoresistive element is made of the above-mentioned base metal, it is easily oxidized when exposed to the outside air, and its magnetoresistive properties tend to deteriorate over time. For this reason, this magnetoresistive part is covered with a protective film, but if a silicon film is formed by the commonly used CVD method, in the process of forming this protective film, Since it is processed at high temperature in the atmosphere, the resistor becomes oxidized and cannot be used. Therefore, an organic resin (such as PIQ) is used as a tumor film for this magnetoresistive element. However, with organic resin, f! Because one side is soft and thin, it easily scratches the magnetoresistive element, making it unable to perform its full function as a protective membrane. There are some problems with this.

This invention was made in view of the above points, and it not only protects the magnetic resistance element from scratches and improves the walking distance wb, but also sufficiently improves the moisture resistance etc. to sufficiently increase reliability. The object is to provide a magnetoresistive device that can be made high.

That is, the magnetoresistive device according to the present invention comprises a magnetoresistive element by forming a ferromagnetic thin film on an insulating substrate, and anodized metal with an electrode portion left on the resistor. This method forms a protective layer consisting of a film.

An embodiment of the present invention will be described below in accordance with the manufacturing process with reference to the drawings. First, as shown in FIG.
1, for example N1-C.

A ferromagnetic material made of an alloy is deposited to form a ferromagnetic material, and this thin film is patterned by etching to form a predetermined magnetoresistive element 12.

Then, as shown in FIG. 2, a metal coating 13 made of, for example, T1 is coated on the entire surface including the magnetoresistive element 12.
Formed by vapor deposition to a thickness of .

Next, on this metal coating 13, as shown in FIG. 3, both end electrode portions 14a of the magnetoresistive body 12 are placed.

The part that will become 14b is masked using Resost 1st1'', and anodized in a 0.1 Ma.L-phosphorus #R solution or /mu.-〇 chlorite acid solution to form an anodic oxide film 16. This anodic oxide film 16 is
After the resist 15 is removed, aluminum is deposited to form electrodes 17m and 11b as shown in FIG. 4, and the magnetoresistive device is completed.

Regarding the magnetoresistive device configured as described above, compared to the conventional magnetoresistive device, temperature and high humidity (121°C) were observed.

2 atm, 100 fk R-H8) test to compare the resistance change over time, as shown in Figure 5, and the resistance change rate due to the magnetoresistive effect (
The output (output) is as shown in Figure 6.

That is, in the case of the magnetoresistive device shown in the above embodiment, the resistance change after 100 hours is less than 2 seconds, as shown by A in FIG. In the case of the conventional type without the presence of , the size increases by about 40 - after 100 hours, as shown by B in Fig. 5.

This is because the ferromagnetic thin film made of the Ni--Co alloy that constitutes the resistor 12 is oxidized. Further, as is clear from the curved line in FIG. 6, the output of the magnetoresistive device shown in the above embodiment hardly changes, whereas the output of the conventional device greatly decreases as shown in curve B. In addition, in the magnetoresistive device shown in the above embodiment, the surface of the magnetoresistive element 120 is covered with the hard anodic oxide film 16 of Ta, so that the mechanical The resistance to scratches caused by external forces is also significantly improved, and a magnetic resistance device with high reliability can be realized.

In addition to Ta, TI, Zr, and Nb4 can be used as the material for the metal coating 13 forming the protective layer.69 These materials can be easily anodized and are compatible with other metals. A material with good adhesion and sufficient electrode strength may be selected. Of course, alloys of these metals or alloys containing gold as a main component of these metals can also be used as materials that exhibit similar effects.

Moreover, as a material constituting the magnetoresistive body 12, N
Of course, it is also possible to use ferromagnetic materials such as 1-F alloys.

In the above embodiment, the protective layer portion formed by the anodic oxide film 16 was shown exposed to the outside, but as shown in FIG. The electrodes 11m, 17 are coated with a film 18 of
Etch on b so that a contact hole is formed.

With this configuration, the high temperature, the resistance change with respect to high temperature, and the resistance value change rate (output) can be made very stable as in the above embodiment, and the resistance is further improved and the yield is lower than that of the conventional example. It can be improved by 25% or more compared to the above, and in particular, the 1iIt wettability is improved by 20 to 30 times.

In Fig. WC7, the same components as those in Fig. 4 are given the same reference numerals, and the explanation thereof will be omitted.

As described above, according to the present invention, the resistance change and output characteristics of the magnetoresistive element, especially in high temperature and high humidity conditions, can be kept sufficiently stable, and the scratch resistance can be significantly improved. As a result, it is possible to obtain a magnetoresistive device that not only improves the yield υ but also sufficiently improves the reliability.

[Brief explanation of drawings]

1 to 4 are diagrams for explaining a magnetoresistive device according to an embodiment of the present invention together with its manufacturing process, and FIGS. 5 and 6 are diagrams for comparing the device according to the above embodiment and a conventional device. FIG. 7 is a cross-sectional configuration diagram illustrating another embodiment of the present invention.

Claims (2)

[Claims] (1) A magnetoresistive element made of a ferromagnetic thin film formed on an insulating substrate, and a protective layer made of a metal film laminated on this resistor and anodized leaving the electrode part. and an electrode metal layer formed on a portion of the metal coating that is not anodized. (2) Claims j! The eel protection layer is formed by further laminating resin, silicon nitride film, silicon nitride film, etc. on the anodized portion of the metal coating. 18. The device according to item 1.