JPS60136909A - Overlapped thin film - Google Patents

Abstract

PURPOSE:To obtain an overlapped thin film where the contact resistance is approximated to zero electrically with improved mutual mechanical bonding by processing the 2nd and 3rd thin films into a pattern different from the pattern of the 1st film on the entire face of a substrate formed with the 3rd thin film. CONSTITUTION:The bonding of the overlapped thin film at the boundary face is made complete by forming a condutive thin film 1 and a conductive thin film 3 for auxiliary use different from the film 1 in this order overlappingly without extracting the films in air. Then the overlapped film is extracted in air and processed as they are to form a thin film pattern 4 made of thins films 1', 3' having the 1st prescribed pattern, the surface rinsing processing of the thin film 3 which is the upper layer is performed, the resultant product is not extracted in air and the thin film 2 is formed continuously, the surface of the thin film pattern 3, contaminated once is rinsed, the thin film 2 is overlapped directly and the bonding between both is made completed. The result is extracted finally in air, the thin film 3' forming the upper layer of the thin film 2 and the thin film pattern 4 is processed to form the conductive thin film 2' having the 2nd prescribed pattern thereby obtaining the desired overlapped thin film.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the formation of an overlapping thin film in which a conductive film with a predetermined pattern different from the conductive film is provided on a conductive film with a predetermined pattern formed on a substrate. The present invention relates to a method, and more specifically, to a method for forming a stacked thin film used in a magnetoresistive element such as a so-called barber pole type magnetoresistive element.

[Background of the invention]

Conventionally, the above-mentioned overlapping thin films have been formed by the process shown in FIG. That is, (1) as shown in FIG. 2(a), forming a first conductive thin film l on the substrate 10, (11) as shown in FIG. 2(b), Processing the conductive thin film to form a first conductive thin film 1' having a first predetermined pattern (tti) As shown in FIG. 2(C), the first conductive thin film 1' A second conductive thin film 2 made of a material different from that of the thin film 1' is deposited on a substrate lO having a Processing the sexual thin film 2,
This process consists of a step of forming a conductive thin film 2' having a second predetermined pattern. In this prior art, the first conductive thin film 1' is a magnetoresistive film made of permalloy alloy (Ni-Fe alloy) or the like, and the second conductive thin film 2' is made of strip electrodes and lead-out conductors made of aluminum or the like. Then, the element shown in FIG. 2) becomes a barber pole type magnetoresistive element. (Refer to Japanese Unexamined Patent Publication No. 134624/1983).

Conventionally, after forming the first thin film 1' (FIG. 2 (b)), the surface of the thin film 1' is cleaned by chemical etching, electrolytic etching, sputter etching, ion milling, etc., and then the thin film 2 is layered. However, if the above treatment is performed in the atmosphere or taken out into the atmosphere after the treatment, an oxide film will be formed on the surface, so the first thin film 1' and the second thin film 2 or 2' The bonding of the overlapped portions with the two is incomplete, the mutual mechanical bonding force is reduced, and the electrical contact resistance of the bonded portions of the two is increased, often resulting in unfavorable results. Therefore, for example, first the first thin film 1' is sputter etched, and then the thin film 2 is formed by vacuum evaporation in the same apparatus without taking it out into the atmosphere. (Fig. 2 (c)) is used. but,
This method cannot be used in cases such as (1) when the thin film 1 has a thickness of only several hundred angstroms or less, and (2) when the thin film 1 is easily susceptible to sputtering damage, which would be fatal.

[“I-specific” of invention]

An object of the present invention is to provide a method for forming a layered thin film that solves all the difficulties of the above-mentioned conventional techniques. To provide a method for forming a stacked thin film that perfectly joins the overlapped parts of a double film made of be.

[Summary of the invention]

In order to achieve the above object, the method for forming a layered film of the present invention employs the following method. This is the first
This will be explained using figures.

That is, first, by sputtering or vacuum evaporation, a conductive thin film 1 and a different auxiliary conductive thin film 3 are formed on the substrate 1O in this order without being taken out into the atmosphere (see FIG. 1(A)). ).The bonding at the interface between thin film 1 and thin film 3 is now complete.

Next, this is taken out into the atmosphere and the overlapping film of thin film 1 and thin film 3 is processed as it is to form a thin film pattern 4 consisting of thin films 1' and 3' having a first predetermined pattern (
Figure 1, mouth 1ro'). Thereafter, this is placed in a sputtering or vacuum evaporation device equipped with a sputter etching mechanism, and the thin film 3' that forms the upper layer of the thin film pattern 4 is first subjected to surface cleaning treatment by sputter etching, and then taken out into the atmosphere as it is. The thin film 2 is continuously formed by sputtering or vacuum evaporation (Fig. 1 (c)).
. The surface of the thin film pattern 3', which has been contaminated once, is cleaned, and the thin film 2 is directly stacked thereon, so that the bond between the two becomes perfect. Finally, if this is taken out into the atmosphere and the thin film 2 and the thin film 3' forming the upper layer of the thin film pattern 4 are processed to form a conductive thin film 2' having a second predetermined pattern, the present invention can be achieved. A stacked thin film is obtained (see Figure 1), (
two'). In this case, it is necessary to use an etching method in which both thin film 2 and thin film 3 are etched, but thin film 1 is not etched.

[Embodiments of the invention]

A case in which the present invention is applied to a magnetoresistive thin film magnetic field will be described below with reference to FIG.

First, on a non-magnetic substrate 1o made of glass or the like, a 200mm thick
A permalloy thin film 1 with a thickness of ~500 amps is further formed by superimposing an aluminum thin film 3 with a thickness of about 100 amps thereon by vacuum evaporation. At this time, two evaporation sources for permalloy and aluminum are prepared in the same vacuum evaporation apparatus, and permalloy and then aluminum are evaporated in series without taking out the substrate 1o into the atmosphere (Figure 1 (a)).
). Note that the permalloy alloy is a Ni-Fe alloy containing 20% by weight of Fe.

Next, the aluminum thin film 3 and the permalloy thin film 1 are processed by a photoetching method to form a thin film pattern 4 of a magnetoresistive sensor consisting of an overlapping film of an aluminum thin film 3' and a permalloy thin film 1' (Figure 1 (b), (mouth').

Next, this substrate 10 is loaded into a vacuum evaporation apparatus equipped with a sputter etching mechanism, and the surface of the upper aluminum thin film 3' is first cleaned by try-etching by sputtering. Then, an aluminum thin film 2 is deposited. The thickness of this film is 2000-3000 Å (FIG. 1C).

Finally, the aluminum thin films 2 and 3' are processed by a well-known photoetching method to form a second conductive thin film 2' having a predetermined pattern, which is used as a lead-out conductor or a strip electrode. In this way, a magnetoresistive thin film magnetic head is completed, which has a structure in which a thin film 1' made of permalloy, which becomes a magnetoresistive film, and a thin film 2' made of aluminum, which becomes a lead-out conductor and a strip electrode, are superimposed (first ), (20).

The above-mentioned magnetoresistive thin film magnetic head is called a barber pole type (details are shown in Japanese Patent Laid-Open No. 134624/1983), and is made of aluminum superimposed on a magnetoresistive film made of a permalloy thin film 1'. The strip electrodes are called short bars and are diagonally wired with a fine line width on the magnetoresistive film (FIG. 1 (2')). As the head becomes finer, the line width of the short bar also becomes on the order of 1 μm.
The contact resistance between the bar and the bar will increase rapidly, and the bar will no longer function as an electrode, and the barber pole type magnetic head will no longer exhibit its unique characteristics. In the conventional method described above, the contact resistance was 10 -5 Ω·m or more, but in this embodiment, this was reduced by more than two orders of magnitude to 10 −7 Ω·cm or less. Furthermore, the magnetic head exhibited characteristics in which the effect of the short bar was considered to be sufficient.

In addition, as the material of the thin film 2 and the thin film 3, aluminum alloy (At-3i, Al-Cu, Al-Cu-3i
), molybdenum, tungsten, etc. may also be used, and each thin film may be made of chromium/gold, molybdenum/
Similar results were also obtained using layered films such as gold/molybdenum.

Further, the thin film 2 and the thin film 3 may be made of the same type of conductive material or may be made of different types of conductive materials.

The material of the thin film 1 varies depending on the purpose and use of the stacked thin films, but in the case of a magnetoresistive element, a ferromagnetic metal material such as a permalloy alloy or a semiconductor material such as silicon is used.

The material of the substrate 10 also varies depending on the purpose and use of the overlapping thin films, but usually an insulating material is used, and in the case of a magnetoresistive element, an insulating non-magnetic magnetic material (for example, glass, 5i02. AI! 203, Ike's insulating ceramics, etc.) are used. Additionally, semiconductor materials (eg, Si, GaAs, etc.) are sometimes used for the substrate.

〔Effect of the invention〕

The method for forming a stacked thin film of the present invention includes the above magnetoresistive element,
In particular, it can be used to form various electrodes of semiconductor devices, such as Schottky electrodes and gates of MO3 devices, in addition to barber-pole magnetoresistive elements, and has a wide range of applications.

[Brief explanation of the drawing]

FIG. 2 is an explanatory diagram of a conventional method for forming overlapping thin films, and FIG. 1 is an explanatory diagram of a method for forming overlapping thin films according to the present invention. In fig. l...First conductive thin film 2...Second conductive thin film 3...Third conductive thin film 1O...Substrate agent Junnosuke Benyado Nakamura

Claims (1)

[Scope of Claims] (1) Form a first thin film made of a predetermined conductive material on a predetermined substrate, and immediately continue to form a second thin film made of a conductive material different from the first thin film. After forming on the first thin film, the first and second thin films are processed to form a predetermined pattern, and then the surface of the second thin film is cleaned by sputter etching, and then immediately continued. A third thin film made of a conductive material different from the first thin film and the same or different from the second thin film is formed on the entire surface of the substrate, and the second and third thin films are A stacked thin film characterized in that it is processed into a predetermined pattern different from the pattern of the first thin film. (2. In the stacked thin film described in claim 1,
A stacked thin film characterized in that the first thin film is a magnetic thin film or a semiconductor thin film. (3) In the stacked thin film according to claim 1 or 2, the second and third thin films are made of aluminum, aluminum alloy, molybdenum, a single layer film of tungsten, chromium-gold, molybdenum-gold. Double layer film, molybdenum
At least one selected from the three-layer gold-molybdenum film
A layered thin film characterized by being a seed.