JPH0927496A - Semiconductor integrated circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a special protective circuit unnecessary by forming a wiring layer made of a normal conductor and a superconductor on a semiconductor substrate. SOLUTION: An Si oxide film 2 is attached on to an Si substrate 1, and on the Si oxide film 2 a wiring layer 3 of a specified pattern is formed. This wiring layer 3 is formed into a two-layer construction made by forming a superconductor 5 on a normal conductor 4 of metal etc. If the current of the wiring layer 3 exceeds a critical current value, the superconductor 5 changes to a normal conducting state, and the resistance value becomes the parallel resistance value (R1 +R2 )/R1 R2 of the resistance value R1 of the superconductor 5 being in a normal conducting state and the resistance value R2 of the normal conductor 4. Accordingly, a current flowing in the wiring layer 3 is controlled by the parallel resistance value (R1 +R2 )/R1 R2 , and does not exceed a critical current value. Besides, when the current flowing in the wiring layer 3 becomes the critical current value or less, the resistance value of the superconductor 5 returns to zero automatically, and the current flowing in the wiring layer 3 is controlled by the resistance value R2 of the normal conductor 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated circuit device, and more particularly to a memory LSI requiring protection from overcurrent,
The present invention relates to a technique effectively applied to a semiconductor integrated circuit device having a microprocessor or a printed circuit board.

[0002]

2. Description of the Related Art In recent years, semiconductor integrated circuit devices have been advanced in speed and power consumption. However, as the power consumption is reduced, the margin for the overcurrent of each element itself becomes smaller, so normally, in order to protect the element against the overcurrent, a protection circuit is connected to the semiconductor integrated circuit device, and Is avoiding.

Incidentally, as such a technique, 1985
Published by Iwanami Shoten on January 10, 2004, Makoto Watanabe, Kunihiro Asada, Kenji Kani, Tatsuo Otsuki (Author), "Design of Iwanami Course Microelectronics 3 VLSI", P91 to P93.

[0004]

However, the present inventor has found that the above-described semiconductor integrated circuit device has the following problems.

That is, since a new protection circuit is required, the cost becomes high. Further, since the protection circuit must be connected to the semiconductor integrated circuit device, the layout of the semiconductor integrated circuit device becomes complicated, the manufacturing process becomes complicated, and the semiconductor integrated circuit device becomes large.

An object of the present invention is to provide a semiconductor integrated circuit device which does not require a special protection circuit.

[0007] The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0008]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

(1) The semiconductor integrated circuit device of the present invention has a wiring layer made of a normal conductor and a superconductor formed on a semiconductor substrate.

(2) The semiconductor integrated circuit device of the present invention comprises a wiring layer formed of a superconductor and having a current path insulated by an insulator on a semiconductor substrate.

(3) The semiconductor integrated circuit device of the present invention comprises a superconductor on a semiconductor substrate, a current path is insulated by an insulator, and a normal conductor is formed on at least one of an upper surface and a lower surface of the superconductor. And a wiring layer that has been formed.

(4) In the semiconductor integrated circuit device of the present invention, a wiring layer made of a superconductor and having a current path partially insulated by an insulator is formed on a semiconductor substrate.

(5) The semiconductor integrated circuit device of the present invention comprises a normal conductor and a superconductor on a semiconductor substrate, and an insulator for insulating a current path is formed at an interface between the normal conductor and the superconductor. It has a wiring layer.

(6) The semiconductor integrated circuit device of the present invention is formed on a semiconductor substrate at a first normal conductor and a superconductor and at an interface between the first normal conductor and the superconductor, and insulates a current path. And a second normal conductor formed on at least one of the upper surface and the lower surface of the first normal conductor and the superconductor.

[0015]

According to the above-mentioned means, since the wiring layer is formed of the normal conductor and the superconductor, when the current flowing through the wiring layer exceeds the critical current value, the superconductor is transformed into the normal conduction state and the wiring The layer is controlled by the parallel resistance value of the resistance value of the normal conductor and that of the normal conductor. When the current flowing through the wiring layer is less than or equal to the critical current value, the current in the wiring layer becomes superconducting.

Further, according to the above-mentioned means, since the current path of the wiring layer made of the superconductor is insulated by the insulator,
When the current flowing through the wiring layer is below the critical current value, a tunnel current flows through the insulator in the superconductor. When the current flowing in the wiring layer exceeds the critical current value, the superconductor transitions to the normal conduction state, so that the current flowing in the wiring layer is completely blocked by the insulator.

Further, according to the above-mentioned means, the current path of the wiring layer made of the superconductor is insulated by the insulator, and the normal conductor is formed on at least one of the upper surface and the lower surface of the superconductor. When the body is in the superconducting state, a tunnel current flows in the insulator, and when the current flowing in the wiring layer exceeds the critical current value, the superconductor transitions to the normal state, so the current flowing in the superconductor is the insulator. However, a current controlled by the resistance value of the normal conductor flows through the wiring layer.

Further, according to the above-mentioned means, since the current path of the wiring layer made of the superconductor is partially insulated by the insulator, when the superconductor is in the superconducting state, the current flows in all the cross sections of the wiring layer. Flowing through. When the current flowing in the wiring layer exceeds the critical current value, the superconductor transitions to the normal conduction state, so that the insulator reduces the effective sectional area of the wiring layer and the effective resistance value of the wiring layer increases.

Further, according to the above-mentioned means, since the insulator for insulating the current path of the wiring layer composed of the normal conductor and the superconductor is formed at the interface between the normal conductor and the superconductor, the superconductor When is in the superconducting state, a tunnel current flows through the insulator. When the current flowing in the wiring layer exceeds the critical current value,
Since the superconductor transitions to the normal state, the current flowing in the wiring layer is completely cut off by the insulator.

Furthermore, according to the above-mentioned means, the first
And an upper surface of the first normal conductor and the superconductor by forming an insulator at the interface between the first normal conductor and the superconductor to insulate the current path of the wiring layer including the normal conductor and the superconductor. And since the second normal conductor is formed on at least one of the lower surface,
When the superconductor is in the superconducting state, a tunnel current flows in the insulator. When the current flowing in the wiring layer exceeds the critical current value, the superconductor transitions to the normal conduction state, so the current flowing in the superconductor is blocked by the insulator, and the resistance of the second normal conductor in the wiring layer. A current controlled by the value flows.

[0021]

Embodiments of the semiconductor integrated circuit device according to the present invention will be described below in detail with reference to the drawings. In all the drawings for explaining the embodiments, those having the same function are designated by the same reference numerals, and the repeated description thereof will be omitted.

(Embodiment 1) FIG. 1A shows a first embodiment of the present invention.
1B is a horizontal cross-sectional view of a semiconductor integrated circuit device according to an embodiment, and FIG. 1B is a vertical cross-sectional view of a wiring layer according to the first embodiment of the present invention.

In FIG. 1, in a semiconductor integrated circuit device, a silicon oxide film 2 is deposited on a silicon substrate 1, and a wiring layer 3 having a predetermined pattern is formed on the silicon oxide film 2. The wiring layer 3 is formed in a two-layer structure in which a superconductor 5 having a perovskite structure of Nb or YB-Cu-O system is laminated on a normal conductor 4 such as metal.

In the superconductor 5, the superconducting state is broken and the state is changed to the normal conducting state when a current more than the critical current value flows, but the superconducting state is maintained while the current less than the critical current value flows. The state is maintained. Moreover, the critical current value of the superconductor 5 is controlled by the magnetic field, the temperature, and the cross-sectional area of the wiring layer 3.

Therefore, when the current flowing through the wiring layer 3 exceeds the critical current value, the superconductor 5 is transformed into the normal conduction state, and the resistance value of the wiring layer 3 is the resistance when the superconductor 5 is in the normal conduction state. Parallel resistance value of the value R ₁ and the resistance value R ₂ of the normal conductor 4 (R ₁ +
R ₂ ) / R ₁ R ₂ . Therefore, the current flowing through the wiring layer 3 is controlled by the parallel resistance value (R ₁ + R ₂ ) / R ₁ R ₂ , and the current that exceeds the critical current value does not flow through the wiring layer 3.

When the current flowing through the wiring layer 3 becomes equal to or lower than the critical current value, the superconductor 5 is in a superconducting state, that is, the resistance value is automatically returned to 0, and the current flowing through the wiring layer 3 is the normal conductor 4. Is controlled by the resistance value R ₂ of.

As described above, according to the first embodiment, since the superconductor 5 is switched to the superconducting state or the normal conducting state according to the magnitude of the current, the superconductor 5 operates as a current limiter, so that the overcurrent can be prevented. It is possible to protect each element of the semiconductor integrated circuit device from overcurrent.

(Embodiment 2) FIG. 2A shows a second embodiment of the present invention.
FIG. 3B is a horizontal cross-sectional view of the semiconductor integrated circuit device according to the embodiment, and FIG. 3B is a vertical cross-sectional view of the wiring layer according to the second embodiment of the present invention.

In FIG. 2, in the semiconductor integrated circuit device, a silicon oxide film 2 is deposited on a silicon substrate 1, and a wiring layer 6 having a predetermined pattern is formed on the silicon oxide film 2. The wiring layer 6 is made of a superconductor 5, and the current path of the wiring layer 6 is insulated by a thin insulator 7.

When the current flowing through the wiring layer 6 is below the critical current value, that is, when the superconductor 5 is in the superconducting state, the current passes through the insulator 7 in the superconductor 5 (tunnel effect).

Therefore, when the current flowing through the wiring layer 6 is below the critical current value, the superconductor 5 is in the superconducting state, so that the tunnel current flows through the insulator 7. When the current flowing through the wiring layer 6 becomes equal to or higher than the critical current value, the superconductor 5 transitions to the normal conduction state, so that the current flowing through the wiring layer 6 is completely cut off by the insulator 7.

As described above, according to the second embodiment, when a current exceeding the critical current value flows through the wiring layer 6, the superconductor 5 and the insulator 7 operate as a current limiter. Each element can be protected from overcurrent.

(Embodiment 3) FIG. 3A shows a third embodiment of the present invention.
FIG. 3B is a horizontal cross-sectional view of the semiconductor integrated circuit device according to the embodiment, and FIG. 3B is a vertical cross-sectional view of the wiring layer according to the third embodiment of the present invention.

In FIG. 3, in the semiconductor integrated circuit device, a silicon oxide film 2 is deposited on a silicon substrate 1, and a wiring layer 8 having a predetermined pattern is formed on the silicon oxide film 2. The wiring layer 8 is made of a superconductor 5, the current path of the wiring layer 8 is insulated by a thin insulator 7, and the normal conductor 4 is formed on the upper surface and the lower surface of the superconductor 5.

When the superconductor 5 is in the superconducting state, the insulator 7
When a tunnel current flows through the wiring layer 8 and the current flowing through the wiring layer 8 exceeds the critical current value, the superconductor 5 transitions to the normal state, so that the current flowing through the superconductor 5 is blocked by the insulator 7. A current controlled by the resistance value R ₂ of the normal conductor 4 flows through the wiring layer 8.

As described above, according to the third embodiment, when a current exceeding the critical current value flows through the wiring layer 8, the superconductor 5 and the insulator 7 act as a current limiter, and the current flowing through the wiring layer 8 is increased. Is controlled only by the resistance value R ₂ of the normal conductor 4, the current of the wiring layer 8 can be easily controlled without considering the resistance value of the superconductor 5 in the normal conduction state. Each element can be protected from overcurrent.

(Embodiment 4) FIG. 4A shows a fourth embodiment of the present invention.
FIG. 6B is a horizontal cross-sectional view of the semiconductor integrated circuit device according to the embodiment, and FIG. 7B is a vertical cross-sectional view of the wiring layer according to the fourth embodiment of the present invention.

In FIG. 4, in the semiconductor integrated circuit device, a silicon oxide film 2 is deposited on a silicon substrate 1, and a wiring layer 9 having a predetermined pattern is formed on the silicon oxide film 2. The wiring layer 9 is made of a superconductor 5, and a part of the current path of the wiring layer 9 is insulated by a thin insulator 7.

When the superconductor 5 is in the superconducting state, the current flows in all the cross sections of the wiring layer 9. Further, when the current flowing in the wiring layer 9 becomes equal to or higher than the critical current value, the superconductor 5 transitions to the normal conduction state, so that the insulator 7 reduces the effective cross-sectional area of the wiring layer 9 and the effective wiring layer 9 Since the resistance value increases, the current is controlled without adding the normal conductor 4. Therefore, each element of the semiconductor integrated circuit device can be protected from overcurrent.

(Embodiment 5) FIG. 5A shows a fifth embodiment of the present invention.
FIG. 7B is a horizontal cross-sectional view of the semiconductor integrated circuit device according to the embodiment, and FIG. 7B is a vertical cross-sectional view of the wiring layer according to the fifth embodiment of the present invention.

In FIG. 5, in the semiconductor integrated circuit device, a silicon oxide film 2 is deposited on a silicon substrate 1, and a wiring layer 10 having a predetermined pattern is formed on the silicon oxide film 2. The wiring layer 10 includes a normal conductor 11 and a superconductor 5, and an insulator 7 that insulates a current path of the wiring layer 10.
Are formed at the interface between the normal conductor 11 and the superconductor 5.

When the superconductor 5 is in the superconducting state, the insulator 7
Tunnel current flows through Further, when the current flowing through the wiring layer 10 becomes equal to or higher than the critical current value, the superconductor 5 transitions to the normal conduction state, so that the current flowing through the wiring layer 10 is completely cut off by the insulator 7.

As described above, according to the fifth embodiment, when a current exceeding the critical current value flows through the wiring layer 10, the superconductor 5 and the insulator 7 operate as a current limiter, so that the semiconductor integrated circuit device Each element can be protected from overcurrent.

(Embodiment 6) FIG. 6A shows a sixth embodiment of the present invention.
FIG. 11B is a horizontal cross-sectional view of the semiconductor integrated circuit device according to the embodiment, and FIG. 9B is a vertical cross-sectional view of the wiring layer according to the sixth embodiment of the present invention.

In FIG. 6, in a semiconductor integrated circuit, a silicon oxide film 2 is deposited on a silicon substrate 1, and a wiring layer 12 having a predetermined pattern is formed on the silicon oxide film 2. The wiring layer 12 is composed of a normal conductor 11 and a superconductor 5, and an insulator 7 that insulates the current path of the wiring layer 12 is formed at the interface between the normal conductor 11 and the superconductor 5. The normal conductor 4 is formed on the upper and lower surfaces of the superconductor 5.

When the superconductor 5 is in the superconducting state, the insulator 7
Tunnel current flows through Further, when the current flowing in the wiring layer 12 becomes equal to or higher than the critical current value, the superconductor 5 transitions to the normal conduction state, so that the current flowing in the superconductor 5 is blocked by the insulator 7 and the wiring layer 12 is normally closed. Resistance value of conductor 4 R ₂
An electric current controlled by is flowing.

As described above, according to the sixth embodiment, when a current exceeding the critical current value flows through the wiring layer 12, the superconductor 5 and the insulator 7 operate as a current limiter, and the wiring layer 1
Since the current flowing through ₂ is controlled only by the resistance value R ₂ of the normal conductor 4, the current of the wiring layer 12 can be easily controlled without considering the resistance value of the superconductor 5 in the normal conduction state,
Each element of the semiconductor integrated circuit device can be protected from overcurrent.

As described above, the invention made by the present inventor is
Although the present invention has been specifically described based on the embodiments, it is needless to say that the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention.

[0049]

Advantageous effects obtained by typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows.

(1) According to the semiconductor integrated circuit device of the present invention, since the wiring layer is formed of the normal conductor and the superconductor, the superconductor acts as a current limiter and can prevent an overcurrent. Each element of the semiconductor integrated circuit device can be protected from the electric current.

(2) According to the semiconductor integrated circuit device of the present invention, the current path of the wiring layer made of a superconductor is insulated by the insulator. Therefore, when a current exceeding the critical current value flows in the wiring layer, the superconductivity is reduced. Since the body and the insulator operate as a current limiter, each element of the semiconductor integrated circuit device can be protected from overcurrent.

(3) According to the semiconductor integrated circuit device of the present invention, the current path of the wiring layer made of a superconductor is insulated by the insulator, and the normal conductor is formed on at least one of the upper surface and the lower surface of the superconductor. Therefore, when a current exceeding the critical current value flows in the wiring layer, the superconductor and the insulator act as a current limiter, and the current flowing in the wiring layer is controlled only by the resistance value of the normal conductor. The current of the wiring layer can be easily controlled without considering the resistance value of the body in the normal conduction state, and each element of the semiconductor integrated circuit device can be protected from overcurrent.

(4) According to the semiconductor integrated circuit device of the present invention, since the current path of the wiring layer made of a superconductor is partially insulated by the insulator, when the current flowing in the wiring layer becomes equal to or higher than the critical current value, Since the insulator reduces the effective sectional area of the wiring layer and increases the effective resistance value of the wiring layer, the current can be controlled without adding a normal conductor, and each element of the semiconductor integrated circuit device can be controlled. It can be protected from electric current.

(5) According to the semiconductor integrated circuit device of the present invention, the insulator for insulating the current path of the wiring layer made of the normal conductor and the superconductor is formed at the interface between the normal conductor and the superconductor. Therefore, if a current exceeding the critical current value flows in the wiring layer,
Since the superconductor and the insulator act as a current limiter, each element of the semiconductor integrated circuit device can be protected from overcurrent.

(6) According to the semiconductor integrated circuit device of the present invention, the insulator for insulating the current path of the wiring layer composed of the first normal conductor and the superconductor is the first normal conductor and the superconductor. Since the second normal conductor is formed on the interface between the first normal conductor and the superconductor, and the second normal conductor is formed on at least one of the upper surface and the lower surface of the first normal conductor and the superconductor, when a current exceeding the critical current value flows in the wiring layer, Since the conductor and the insulator act as a current limiter and the current flowing through the wiring layer is controlled only by the resistance value of the normal conductor, the resistance value of the superconductor in the normal conduction state is not taken into consideration. Can be easily controlled, and each element of the semiconductor integrated circuit device can be protected from overcurrent.

(7) According to the semiconductor integrated circuit device of the present invention, according to the above (1) to (6), a protection circuit against an overcurrent can be formed in the wiring layer without using a special protection circuit. Therefore, the degree of freedom in layout can be increased, the manufacturing process can be simplified, and an inexpensive and compact semiconductor integrated circuit device can be realized.

[Brief description of drawings]

FIG. 1A is a horizontal sectional view of a semiconductor integrated circuit device according to a first embodiment of the present invention, and FIG. 1B is a vertical sectional view of a wiring layer according to a first embodiment of the present invention.

2A is a horizontal cross-sectional view of a semiconductor integrated circuit device according to a second embodiment of the present invention, and FIG. 2B is a vertical cross-sectional view of a wiring layer according to a second embodiment of the present invention.

3A is a cross-sectional view of a semiconductor integrated circuit device according to a third embodiment of the present invention, and FIG. 3B is a vertical cross-sectional view of a wiring layer according to a third embodiment of the present invention.

FIG. 4A is a horizontal sectional view of a semiconductor integrated circuit device according to a fourth embodiment of the present invention, and FIG. 4B is a vertical sectional view of a wiring layer according to a fourth embodiment of the present invention.

5A is a horizontal cross-sectional view of a semiconductor integrated circuit device according to a fifth embodiment of the present invention, and FIG. 5B is a vertical cross-sectional view of a wiring layer according to a fifth embodiment of the present invention.

6A is a horizontal sectional view of a semiconductor integrated circuit device according to a sixth embodiment of the present invention, and FIG. 6B is a vertical sectional view of a wiring layer according to a sixth embodiment of the present invention.

[Explanation of symbols]

 1 Silicon substrate 2 Silicon oxide film 3,6,8,9,10,12 Wiring layer 4,11 Normal conductor 5 Superconductor 7 Insulator

Claims (6)

[Claims] 1. A semiconductor integrated circuit device having a wiring layer made of a normal conductor and a superconductor formed on a semiconductor substrate. 2. A semiconductor integrated circuit device, wherein a wiring layer made of a superconductor is formed on a semiconductor substrate, and a current path of the wiring layer is insulated by an insulator. 3. The semiconductor integrated circuit device according to claim 2, wherein a normal conductor is formed on at least one of an upper surface and a lower surface of the superconductor. 4. A semiconductor integrated circuit device, wherein a wiring layer made of a superconductor is formed on a semiconductor substrate, and a current path of the wiring layer is partially insulated by an insulator. 5. A wiring layer made of a normal conductor and a superconductor is formed on a semiconductor substrate, and an insulator for insulating a current path of the wiring layer is formed at an interface between the normal conductor and the superconductor. A semiconductor integrated circuit device characterized by the above. 6. A wiring layer is formed on a semiconductor substrate, and the wiring layer is formed on a first normal conductor and a superconductor, and at an interface between the first normal conductor and the superconductor. A semiconductor integrated circuit device comprising: an insulator that insulates a path; and a second normal conductor formed on at least one of an upper surface and a lower surface of the first normal conductor and the superconductor.