JPS63318013A - Superconductive wiring material - Google Patents

Abstract

PURPOSE:To provide a wiring material with high density and without wiring resistance by forming a superconductor of oxide type on a mono-crystal base plate with mono-crystals, and inclining the crystal surface to the base plate surface. CONSTITUTION:The superconductor of oxide type is oxide of rare earth and Co such as Ba2CuO4, and the crystal indicates perovskite structure. When a mono-crystal film having (011) surface of Ba2CuO4 is formed on, e.g., a sapphire surface base plate 1, a set of (001) surfaces parallel with each other and without electrical contact will be formed, in which a direction 4 as superconductive condition and a direction 5 to become an electrically insulating body coexist on the same base plate surface. On this surface terminals 6-8 are formed with Cu etc., by means of evaporation. Thereby the terminals 6, 7 lying on the same surface (001) are given electrical continuity without any electric resis tance, while those 7, 8 are put in insulated state, and consideration on arrange ment of these terminals should enable mounting of elements in high density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to high-density wiring materials and substrates used in electronic computers and the like, and particularly to superconducting wiring materials that do not generate heat and are suitable for mounting high-density elements.

[Conventional technology]

Conventionally, the method of wiring elements in high density was
As described in 35825, a metal such as Cu or AQ is combined with a photoresist, a resin such as PIQ, or a metal such as AQ 203.
There is a method of embedding the metal in a gap formed by an oxide such as S i 02 and obtaining electrical continuity between elements using this metal. However, with this wiring method, as the degree of integration increases, the wiring metal resistance between elements increases cumulatively, causing problems such as a reduction in signal transmission speed and heat generation.

As materials without electrical resistance, metals such as NbaSn or compound superconductors are conventionally known. However, these materials become superconducting only at extremely low temperatures of -250 degrees Celsius or lower, and semiconductors do not operate at such temperatures.

On the other hand, in recent years, certain oxides have shown superconductivity,
It has become clear that the superconducting transition point is also much higher than that of conventional metal/compound superconductors.

These oxides, when the rare earth metal is M, are M2Cu0
It is characterized by having a perovskite structure represented by 4. A plane made of Cu and O is formed on the (001) plane within the perovskite unit cell, and superconductivity occurs within this plane. A polycrystalline thin film can be easily formed using this material by sputtering, and by using this material in place of the aforementioned wiring materials Cu and Afl, a wiring material that does not generate heat due to wiring resistance can be easily obtained. However, the actual
・When the wiring width is narrowed to increase the packing density, the wiring width and the crystal grain size become almost the same, and there is a part where the superconducting layer mentioned above does not contact between the crystal grains, which has the disadvantage that it does not function as a wiring material. .

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into account the reduction in wiring resistance, and wiring materials using oxide superconductors also have the disadvantage that they cannot respond to miniaturization of wiring.

An object of the present invention is to provide a wiring material with high density and no wiring resistance.

[Means for solving problems]

The above purpose is to make an oxide superconductor into a single crystal by fabricating it on a single crystal substrate, and by tilting the (OO1) crystal plane with respect to the substrate surface, the direction of the superconducting state and the current flow in the film plane are determined. This is achieved by creating a direction in which no flow occurs and applying this direction to the wiring material.

[Effect]

Oxide superconductors are oxides of rare earths and copper, such as Ba 2 Cu O4. The crystal form is a perovskite structure and exhibits superconductivity in the C plane shown in FIG.

So, for example, on a sapphire (0001) Go board, Ba2
If a single crystal film of CuOa with a (011) plane is fabricated, the (0
01) A set of surfaces is created. If this is viewed from perspective, it can be seen that the superconducting direction 4 and the electrically insulating direction 5 exist within the same substrate plane, as shown in FIG. This side”
Second, if the terminal parts 6, 7, 8 are formed of Cu or the like by vapor deposition, sputtering, or plating in the relationship shown in the figure, 6 and 7 on the same (001) plane are electrically conductive without electrical resistance. 6 and 8 and 7 and 8 are in an insulated state.

If the arrangement of these terminal portions is taken into consideration, high-density device mounting becomes possible. Furthermore, if the sapphire (0001) plane is cut out at an angle from the substrate surface, Ba2CuOa's (0
11) Azimuth and inclination Since the (001) plane is also inclined, the distance between superconducting layers can also be changed.

In addition, if more complicated inter-element wiring is required,
An insulating single crystal film such as AQ or zOa is epitaxially grown on the wiring material shown in Fig. 1, and an oxide superconducting layer is further formed on top of it, and a multilayer wiring is connected to the lower layer by Cu or the like after forming through holes. If used, connections between arbitrary terminals can be made.

〔Example〕

B a 2 Cu O 4 was sintered into a shape with a diameter of 100 w and a thickness of 5 fields, and sputtering was performed using this as a target. A sapphire substrate is used as the substrate, high frequency input power is 3 ood, Ar gas pressure is 2 X I Q-2 Torr.
.

O2 gas pressure 0, 2 x 10''-2 Torr substrates were water cooled.

A high frequency bias was applied to the substrate, and the average DC potential was adjusted to 1200V. When the plane orientation of the sapphire substrate was changed as shown in Table 1 below under the above conditions, BazCu*4 single crystal films with specific plane orientations were grown. Thickness is 1
It was set as μm.

Table 1 According to this example, it was found that a single crystal oxide superconductor could be formed on a sapphire substrate.

〔Effect of the invention〕

According to the present invention, an oxide superconductor having a specific plane orientation can be formed on a substrate, and a wiring material that can be highly densified and has no wiring resistance can be formed.

[Brief explanation of drawings]

Figure 1 shows Ba2Cu04 formed on a sapphire substrate.
FIG. 2 is a cross-sectional view showing the plane orientation relationship of the thin film, FIG. 2 is a perspective view of FIG. 1, and FIG. 3 is a structural diagram showing the crystal plane of perovskite. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Oxide superconductor, 3... Perovskite (001) plane, 4... Superconducting direction, 5...
・Insulator No. 1 Port No. 2 Diagram

Claims (1)

[Claims] 1. A superconducting wiring material consisting of a conductive film formed on a substrate and an electrode layer formed thereon, characterized in that the substrate is a single crystal insulator and the conductor is an oxide superconductor single crystal film. .