JPH01780A - Connection body device and its manufacturing method - 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 superconductor, hereinafter referred to as superconductor. ) etc., and particularly relates to the structure of a connector device incorporating a superconductor thin film such as a compound and its manufacturing method.

Conventional technology In the past, niobium nitride (NbN) and germanium niobium (
N b s G e ), etc. were known.

The superconducting transition temperature of these materials was at most 24°. Among those expected to have an even higher transition temperature are the Ba-La-Cu-0 perovskite ternary compounds;
etc. were proposed. However, recent research suggests that Y-Ba-Cu-○-based materials may exceed liquid nitrogen temperatures (M., Wu et al., Physical Review Letters).
w Letters) vof, 58, N009, P
P, 908910 (1987)), in reality, 90°
Superconducting compounds with transition temperatures above .

Problems to be Solved by the Invention Single-crystalline superconducting thin films have higher critical current densities in interconnects, etc. than polycrystalline superconducting thin films; It was also used as the active region of active elements, and its practical application was urgently sought.
Even if a thin film of -Cu-0-based compounds is formed by sintering or sputtering, it is relatively easy to obtain ceramic powders or lumps that exhibit superconductivity. It was difficult to obtain a uniform thin film with strong single crystallinity. However, as far as the inventors have known, even in the sputtering method, sapphire (α-A12
03>, we have found that using single crystals such as magnesium oxide, spinel, silicon, gallium arsenide, etc. is very effective for forming superconducting thin films with good single crystallinity. Furthermore, in the thin film formed in this way, the C axis of the crystal tends to be perpendicular to the plane of the substrate (and, moreover, the carrier density of the superconducting current flowing in the direction of this plane (perpendicular to the C axis) is It was found that the carrier density of the superconducting current flowing in the direction along the C-axis (parallel to the C-axis) is several times larger than that of the carrier density.In other words, it is easier to flow the superconducting current in the direction perpendicular to the C-axis, It was difficult to extract the superconducting current in the direction parallel to the C axis.Furthermore, the coherence length of the superconductor was several tens of nanometers in the direction perpendicular to the C axis.
It is known that in the direction parallel to the C axis, there is a difference of several nanometers, which is also several times larger. In this way, thin film superconductors made of compounds such as Y-Ba-Cu-0,
For example, when used in applications such as wiring for integrated circuit interconnection devices, there is a problem in that the anisotropy of superconducting current that tends to flow in the horizontal plane of the substrate makes it difficult to extract current in the direction perpendicular to the plane. Ta.

Means for Solving the Problem In order to solve this problem, the present invention provides a first ribbon-shaped thin film formed on a substrate and exhibiting conductive anisotropy that tends to flow in a plane parallel to the substrate. , a groove formed from the surface of the first ribbon-shaped thin film, and an isotropic second groove formed in connection with the groove and having no conductive anisotropy.
a ribbon-shaped thin film; and a connecting body device characterized in that the current is taken out from the side surface of the groove of the first ribbon-shaped thin film to the second ribbon-shaped thin film; a step of forming a first ribbon-shaped thin film exhibiting conductive anisotropy that easily flows in the plane direction; a step of forming a groove from the surface of the first ribbon-shaped thin film; and a step of forming a conductive thin film connected to the groove. The process consists of a step of forming an isotropic second ribbon-like thin film with no visible anisotropy, and extracting current from the side surface of the groove of the first ribbon-like thin film to the second ribbon-like thin film. A method for manufacturing a connecting body device having characteristics is provided.

Function: By the method of the present invention, for example, Y-Ba-Cu-
By forming a groove from the surface of the anisotropic ribbon-like thin film of a zero-based material, it becomes easy to extract current flowing in a plane parallel to the substrate from the side surface of the groove. . Therefore, it is sufficient to form a conductive film in the form of a ribbon-like thin film without anisotropy in contact with the side surfaces of this groove. At this time, if these two ribbon-shaped three films exhibit superconductivity, a multilayer wiring without electrical resistance can be realized. Furthermore, if the groove is deep, it is difficult to uniformly fill the groove with a ribbon-like thin film without anisotropy.
It is preferable that the side surfaces of the groove are slightly tapered.

In order to extract the maximum amount of current from the side surfaces of the groove, it is preferable to etch the groove to the bottom of the anisotropic ribbon-like thin film to maximize the area of the side surfaces. on the other hand,
If the coherence length of the thin film in the direction perpendicular to the plane of the anisotropic thin film is relatively large relative to the thickness of the thin film, it is not necessarily necessary to etch the grooves all the way to the bottom of the thin film. In other words, even if a thin film with a thickness equal to or less than the coherence length remains under the groove, it is possible to extract the superconducting current from the bottom of the groove. Furthermore, when the groove is formed into a tapered shape, the volume of the current extraction region is determined by the product of the longitudinal coherence length of the thin film and the increased effective lateral area of the groove due to the tapered side surfaces of the groove. This achieves an improvement in the efficiency of current extraction, since it can be made larger.

Considering this point as well, it is preferable to form the groove portion in a tapered shape.

EXAMPLE Hereinafter, the structure of a connecting body device using superconducting wiring according to the method of the present invention will be described in detail as a first example with reference to FIG.

Substrate 100 of crystalline sapphire (α-A 1203)
On top, C formed at a substrate temperature of 700-1000″C
Y-Ba whose axis is arranged in a direction substantially perpendicular to the plane of the substrate
-A ribbon-shaped superconducting thin film wiring 110 of approximately 1000 nanometers thick made of Cu-0 based crystal, grooves 140A and 140B opened from the surface of a silicon oxide film 120 covering the surface of this thin film, and Polycrystalline Y- (formed at a substrate temperature of 200-500"C) connected to the groove 140
Superconducting thin film wirings 160A and 160B made of Ba-Cu-0 based crystal and having a thickness of about 1500 nanometers are formed. Here, the superconducting wiring 160C is a wiring that passes over the superconducting wiring 110. According to the structure of the present invention, the current flowing from the wiring 160A through which the current can flow isotropically is
The wiring 16 flows uniformly from the side surface 150A of the groove 140A formed in the groove 10, and the wiring 16 flows from the side surface 150B of the groove 140B.
It was successfully taken out at 0B. If an opening is provided in the oxide film 120 under the wiring 160C in this arrangement,
The wiring 110 and the wiring 16 are separated without forming a groove in the wiring 110.
0C, the current flowing from the wiring 160A does not flow into the wiring 160C, and most of the current is extracted from the side surface 150B of the groove 140B to the wiring 160B.

The structure of a connecting body device using superconducting wiring according to the method of the present invention will be described in detail as a second embodiment with reference to FIG. 2.

As shown in FIG. 2, it has the same configuration as the first embodiment shown in FIG. It has a tapered shape. This tapered groove provided the following effects. If the groove with vertical side surfaces is deep, it will be difficult to uniformly embed the ribbon-shaped thin film wirings 160A and 160B in the groove. It becomes easy to uniformly embed the wirings 160A and 160B in the grooves.Furthermore, when the grooves are formed in a tapered shape, the longitudinal coherence length of the thin film wiring 110 and the tapered side surfaces of the grooves make it easier. The volume of the current extraction area determined by the product of the increased effective lateral area of the groove portion is large.Thereby, an improvement in the efficiency of current extraction is achieved.

3(a) to 3(c) show a third embodiment of the method of manufacturing a connecting body device using superconducting wiring according to the method of the present invention.
This will be explained in detail with reference to .

Figure 3 (a) Throat (, crystalline sapphire (α-A
700-1000 on the substrate 100 of I20a)
A ribbon-shaped superconducting thin film of about 1000 nanometers thick of Y-Ba-Cu-0 system crystals is formed at a substrate temperature of "C" so that the C-axis is aligned in a direction substantially perpendicular to the plane of the substrate. A ribbon-shaped wiring 110 is formed by a normal photoetching process and physical etching using argon or the like, and an insulating film 120 such as a silicon oxide film is formed on the entire surface.
was formed.

As shown in Fig. 3(b), a depth of about 80 mm is etched by physical etching using argon or the like in a normal photo-etching process.
Groove 1'40 with nearly vertical sides of 0 nanometers
A, 140B is formed on the entire surface, polycrystalline (substrate temperature 2
A superconducting thin film 160 of approximately 1500 nanometers thick is deposited using Y-Ba-Cu-0 crystals (formed at 00-500°C), and resist patterns 180A, 180B, and 180C are formed by a normal photoetching process. Formed.

As shown in FIG. 3(C), resist pattern 180A,
Using 180B and 180G as masks, superconducting thin film 160
A ribbon-shaped superconducting wiring 160A is formed by physical etching using argon or the like.

160'B and 160'C were formed, and the resist 180A and the like were removed. Here, the superconducting wiring 160C is a wiring that passes over the superconducting wiring 110.

As described above, according to the manufacturing method of the present invention, the current flowing from the wiring 160A through which the current can flow isotropically is
10, uniformly flows from the side surface of the groove 140A formed in the groove 140B, and flows from the side surface 150B of the groove 140B to the wiring 160B.
It was taken out in good condition.

A fourth embodiment of the method of manufacturing a connecting body device using superconducting wiring according to the method of the present invention is shown in FIGS. 4(a) to 4(C).
This will be explained in detail with reference to .

FIG. 4(a) Throat (crystalline sapphire substrate 100
Above is the first layer of a Y-Ba-Cu-0 based ribbon-shaped superconducting thin film with a thickness of approximately 1000 nanometers, which exhibits conductive anisotropy that tends to flow in a plane parallel to the substrate. Wiring 1
10 and depositing a silicon oxide film 120 that will become the insulating film between the eyebrows of the two-layer wiring, Y-! 3a-Cu-
Wiring 20 of the second layer of ribbon-shaped superconducting thin film made of 0-based material
Form 0A, 200B, 200C, and apply it to the entire surface.
A silicon oxide film 220 was deposited to serve as an insulating film.

FIG. 4(b) The second wiring 200 is etched from the surface of the silicon oxide film by etching using a combination of a normal photoetching process and a reactive gas or argon.
After penetrating through A and 200B and further forming an opening having a groove in the first wiring 110, the entire surface is coated with a thickness of approximately 1000°C at a relatively low substrate temperature (formed at a temperature of 200-500°C). Nanometer polycrystalline Y-Ba-Cu-0
A superconducting thin film 160 of the system was deposited.

In FIG. 4(c), the surface of the superconducting thin film 160 was back-etched flat by etching with argon or the like, leaving the superconducting thin films 160A and 160B in the grooves.

As described above, according to the manufacturing method of the present invention, the current flowing from the wiring 20OA having current anisotropy is transferred to the trench 14.
The current uniformly flows into the non-anisotropic wiring 160A formed in 0A, further passes through the first layer wiring 110 where the current has anisotropy, and flows into the non-anisotropic wiring 160B from the side surface of the groove 140B. The current was successfully taken out, and finally the current reached the second layer wiring 200B. In this way, a superconducting current path between the wirings 20OA and 200B could be formed while avoiding the second layer wiring 200C.

In addition, as an example of the present invention, the method of forming the wiring has been mainly described, but the first layer wiring 11 with excellent crystallinity has been described.
It goes without saying that the crystal part of the 0 etc. can be directly used as a region for various active elements such as Josephson, bipolar, etc., and therefore more advanced superconducting electronic circuits can be formed. In addition, as an example of the present invention, an example using a superconducting current has been described, but if an anisotropy in the conductivity of a ribbon-like thin film is observed in line with the gist of the present invention, it is not necessarily necessary to use a superconducting current. However, the method of the present invention is also applicable to cases where normally conducting current is used.

Effects of the Invention According to the structure and manufacturing method of the present invention, in particular, it is possible to provide an integrated connecting body device in which wiring, elements, etc. are formed while connecting superconducting thin films having anisotropy of current to each other in a good manner. became possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the structure according to the present invention, FIG. 2 is a sectional view showing a second embodiment of the structure according to the present invention, and FIGS. A series of process cross-sectional views showing the third embodiment of the manufacturing method according to the invention, FIGS. 4(a)-(
c) is a series of process cross-sectional views showing a fourth embodiment of the manufacturing method according to the present invention. 100...Substrate, 110.200...Anisotropic superconducting film, 120.220...Insulating film, 140...Groove portion,
150: Side surface of groove, 160: Isotropic superconducting film, 180: Resist. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2! Tel's R Dentaka Gun Figure 3 Figure 4 770Ttl's Superden 11ff

Claims (7)

[Claims] (1) A first ribbon-shaped thin film formed on a substrate and exhibiting conductive anisotropy that tends to flow in a plane parallel to the substrate; and a groove formed from the surface of the first ribbon-shaped thin film. , an isotropic second ribbon-shaped thin film with no conductive anisotropy formed in connection with the groove,
A connecting body device characterized in that a current is taken out from a side surface of a groove of a first ribbon-like thin film to a second ribbon-like thin film. (2) The connecting body device according to claim 1, wherein the side surface of the groove portion is tapered. (3) Claim 1, characterized in that the bottom surface of the groove penetrates at least the first ribbon-shaped thin film.
The connecting body device according to item 1 or 2. (4) The connector device according to any one of claims 1 to 3, wherein the ribbon-shaped thin film is a superconducting film. (5) A patent characterized in that the thickness of the thin film left between the bottom of the groove and the bottom of the first ribbon-like thin film is at least about the same or less than the coherence length in the direction perpendicular to the substrate. A connecting body device according to claim 4. (6) forming a first ribbon-shaped thin film on the substrate, which exhibits conductive anisotropy that easily flows in a plane direction parallel to the substrate, and forming grooves from the surface of the first ribbon-shaped thin film; and a step of forming an isotropic second ribbon-shaped thin film with no conductive anisotropy connected to the groove, the side surface of the groove of the first ribbon-shaped thin film being connected to the groove. A method for manufacturing a connecting body device, characterized in that a current is taken out from a thin ribbon to a second ribbon-shaped thin film. (7) The method for manufacturing a connecting body device according to claim 6, wherein the ribbon-shaped thin film is a superconducting film.