JPH07211865A - Inductor - Google Patents

Abstract

PURPOSE:To increase inductance and to reduce the size of an inductor by covering a lines, which are aligned so that currents flow in the reverse direction through the neighboring lines, with a high-permeability material. CONSTITUTION:A substrate 1 is an insulating (SI-) GaSa substrate, an insulating film 2 is a silicon dioxide film, a gold film 3 is a line constituting inductance, an insulating film 4 is a silicon nitride film and a high-permeability material film 5 is an amorphous metal film, a ferrite film or the like. Here, the silicon nitride film 4 having the thickness of 500Angstrom is deposited on the meander line using the line or the conventional gold film 3 or the like. The amorphous metal film 5 having the thickness of 1mum is further deposited on the film 4. As the method for reducing the occupying area on the substrate of an inductor, the conventional inductance line is used. The magnetic field generated by the current flowing through the inductor is made large by covering the periphery of the inductor with the high-permeability material, and the inductance is made large. As a result, the size of the inductor is reduced.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a monolithic microwave.
The present invention relates to an inductor formed on a substrate such as an IC (MMIC).

In recent years, as a microwave IC (MIC), an MM monolithically formed on a semiconductor substrate from a hybrid IC.
IC development is actively carried out. However, since a lumped constant circuit is used as the MMIC formation technology in the low frequency region,
The dimensions of passive circuit elements are relatively large compared to active elements.
That is, it is difficult to reduce the size of the MMIC because of its large size, and it is difficult to reduce the cost. In particular, it is desired to reduce the size of the inductor, which is one of the passive circuit elements.

[0003]

2. Description of the Related Art Conventionally, lumped-constant type inductors on MMICs include meander lines and spiral lines. Meander lines are used for medium-sized inductances, and spiral lines are used for relatively large inductances.

In any case, basically, a structure in which a line is wound is used to create the inductance of the circuit, and the surrounding area is air or vacuum with a low magnetic permeability,
The area of the inductor is increasing.

[0005]

SUMMARY OF THE INVENTION In the present invention, as a structure of an inductor on an MMIC, the structure of a conventional meander line, spiral line, or the like is basically used to reduce the size and reduce the cost. To aim.

[0006]

[Means for Solving the Problems] To solve the above problems (see FIGS. 1 and 3), 1) an inductor formed on a substrate, in which adjacent lines are arranged so that current flows in the opposite direction. Railroad track 3
And an inductor having an insulating film 4 covering at least the upper part of the line, and a high-permeability material film 5 covering the insulating film and having a magnetic permeability larger than vacuum, or 2) formed on a substrate Line 3A that is an inductor and is arranged so that current flows in the same direction in adjacent lines
And an insulating film 4 covering at least an upper portion of the line, and a high-permeability material film 5 covering the insulating film and having a magnetic permeability larger than that of vacuum, and the high-permeability material film is adjacent to the line. This is achieved by the inductors being separated between.

[0007]

In the present invention, as a method of reducing the occupied area of the inductor on the substrate, the conventional inductor line is used as described above. However, by covering the inductor with a high-permeability material, the inductor flow The magnetic field generated by the current is increased, which increases the inductance and consequently reduces the size of the inductor.

As a technique similar to the present invention, it is known to form an inductor on a substrate of a high magnetic permeability material, or to cover a chip inductor mounted on the substrate with a high magnetic permeability material.

On the other hand, according to the present invention, in an inductor formed on a substrate, such as a meander line, in which an adjacent line has a current flowing in the opposite direction, a high permeability is directly provided on or around the line. The inductance is increased by coating a magnetic susceptibility material.

On the other hand, when current flows in the same direction in adjacent lines such as a spiral line, the magnetic fields in the adjacent lines are generated in opposite directions, so that the high-permeability material is uniformly coated over the entire inductance. Is less effective. Therefore, in this case, the self-inductance is increased by covering the magnetic field generated by its own line with a high magnetic permeability material, that is, by separating the high magnetic permeability material between adjacent lines.

[0011]

Embodiments FIGS. 1A and 1B are explanatory views of Embodiment 1 of the present invention. FIG. 1 (A) is a plan view and FIG. 1 (B) is a sectional view.

In the figure, 1 is a semi-insulating (SI-) GaAs substrate, 2 is an insulating film which is a silicon dioxide (SiO ₂ ) film, 3 is a line which constitutes an inductor, and is a gold (Au) film, and 4 is an insulating film. The silicon nitride (Si ₃ N ₄ ) film, 5 is a high permeability material film, such as an amorphous metal film or a ferrite film.

In this embodiment, a Si ₃ N ₄ film 4 with a thickness of 500 Å is deposited on a meander line using a line such as a conventional Au film 3 and a 1 μm thick amorphous film of CoZrNi system or the like is further deposited thereon. A metal film 5 is deposited.

FIGS. 2A to 2C are explanatory views of the second embodiment of the present invention. This embodiment is a plan view of an inductor wound so that the current directions of adjacent lines are opposite to each other.
Is the same as.

[0015] As shown, the examples are line 3 adjacent either be wound such that the reverse current path as meander lines, Si ₃ N ₄ in FIG. 1 thereon as an insulating film 4
Instead of the film, a 1000 Å thick SiO ₂ film is deposited, and an amorphous metal film 5 with a thickness of 1 μm is further deposited on it.

FIGS. 3A and 3B are explanatory views of the third embodiment of the present invention. FIG. 3A is a plan view and FIG. 3B is a sectional view.
In this embodiment, an adjacent line 3A is an inductor in which a current path in the same direction as a spiral line is formed, and a thickness above the inductor is set.
A 500 Å Si ₃ N ₄ film 4 was deposited and a thickness of 0.5
A μm amorphous metal film 5 is deposited, and the amorphous metal film 5 between lines is formed into a separated structure.

FIG. 4 is an explanatory view of the fourth embodiment of the present invention.
The figure shows a plan view, and the cross-sectional view is similar to FIG. In this embodiment, the inductor is wound such that the adjacent line 3 becomes a current path in the opposite direction like a meander line, and a SiO ₂ film with a thickness of 1000 Å is deposited as an insulating film 4 on the line. 1 μm thick amorphous metal film 5 is deposited on
In addition, the amorphous metal film 5 between the lines is formed in a separated structure.

FIG. 5 is an explanatory view of the fifth embodiment of the present invention.
In the figure, the thickness of the insulating film on the semiconductor substrate 1 is 1000 Å
Of SiO ₂ film 4 is deposited, a 2000 Å-thick ferrite film 6 is deposited on it, and a 3 μm-thick Au film 3 is formed on it as a line.
Or 3A is formed and this is used as a mask.
And SiO ₂ film 4 is etched, and the thickness of 1000
A Å SiO ₂ film 4 is deposited, a 0.5 μm-thick ferrite film 5 is further deposited as a high-permeability material film, and the ferrite film 5 between lines is separated.

FIG. 6 is an explanatory diagram of a sixth embodiment of the present invention.
In the figure, the thickness of the insulating film on the semiconductor substrate 1 is 1000 Å
SiO ₂ film 4 is deposited, and a line with a thickness of 3 μm is formed on it.
Form Au film 3 or 3A, and use this as a mask for SiO ₂ film 4
Is etched, and a 1000 Å thick SiO ₂ film
And a ferrite film 5 with a thickness of 0.5 μm as a high-permeability material film.
Form a separated structure.

FIG. 7 is an explanatory diagram of a seventh embodiment of the present invention.
In the figure, a 3 μm-thick Au film 3 or 3A is formed as a direct line on a semi-insulating semiconductor substrate 1, the semiconductor substrate is etched and dug down using this as a mask, and further 1000 Å thick SiO _{2 is formed} on top of it. A film 4 is deposited, a 0.5 μm thick ferrite film 5 is further deposited as a high-permeability material film, and a ferrite film 5 between lines is formed in a separated structure.

In the above embodiments, CoZr is used as the high magnetic permeability material.
Although the Ni-based amorphous metal film and ferrite are used, the present invention is not limited to this, and other various permalloys, ferrites, amorphous metal materials and the like may be used.

[0022]

According to the present invention, as the structure of the inductor on the MMIC, the structure such as the conventional meander line or spiral line is basically used, and the size can be reduced and the cost can be reduced. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of Embodiment 3 of the present invention.

FIG. 4 is an explanatory diagram of Embodiment 4 of the present invention.

FIG. 5 is an explanatory diagram of Embodiment 5 of the present invention.

FIG. 6 is an explanatory diagram of Embodiment 6 of the present invention.

FIG. 7 is an explanatory diagram of Embodiment 7 of the present invention.

[Explanation of symbols]

1 SI-GaAs substrate as a semiconductor substrate 2 SiO ₂ film as an insulating film 3, 3A Au line as a line forming an inductor 4 Insulating film Si ₃ N ₄ film or SiO ₂ film 5, 6 High magnetic permeability material film as an amorphous metal film Or ferrite film

Claims (2)

[Claims] 1. An inductor formed on a substrate, in which adjacent lines are arranged so that current flows in opposite directions, and an insulating film covering at least the upper part of the line.
An inductor comprising (4) and a high-permeability material film (5) which covers the insulating film and has a higher magnetic permeability than vacuum. 2. An inductor formed on a substrate, wherein a line (3A) is arranged so that current flows in the same direction in adjacent lines, and an insulating film covering at least an upper part of the line.
(4) and a high-permeability material film (5) which covers the insulating film and has a magnetic permeability greater than that of vacuum, and the high-permeability material film is separated between adjacent lines. An inductor characterized by.