JPH1074624A - Inductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductor element in which the generation of an eddy current and a parasitic capacitance can be reduced. SOLUTION: An inductance element is composed of spiral-formed floating conductor 2 formed on a substrate 3 and an inductor conductor 1 which will be opposingly arranged on the floating conductor 2 through an insulating layer. Prescrived voltage is applied to the inductor conductor 1, and the floating conductor 2 is brought into a floating state. As above-mentioned, as the floating conductor 2 is interposed between the inductor conductor 1 and the substrate 3, the eddy current generated on substrate surface and the stray capacitance generated between the substrate 3 and the inductor conductor 1 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inductor element formed by using a spiral pattern.

[0002]

2. Description of the Related Art There is known a semiconductor circuit in which a spiral pattern is formed on a semiconductor substrate by using a thin film forming technique and the pattern is used as an inductor element.

FIG. 11 is a view for explaining the magnetic flux generated from this type of inductor element. When a predetermined current flows through the spiral-shaped inductor element 101 shown in FIG. 2, a magnetic flux is generated in a direction perpendicular to the surface of the semiconductor substrate 102, that is, in a direction penetrating the semiconductor substrate 102, as indicated by an arrow in FIG. The magnetic flux in this direction may cause eddy currents and stray capacitance, and may adversely affect the operation of other semiconductor elements formed on the semiconductor substrate 102.

The present invention has been made in view of the above points, and an object of the present invention is to provide an inductor element capable of reducing the generation of eddy current and stray capacitance as compared with the related art.

[0005]

In order to solve the above-mentioned problems, an inductor element according to the present invention comprises an inductor conductor and a floating conductor having substantially the same shape formed on a substrate with an insulating layer interposed therebetween. Use a floating structure. That is, by interposing a floating conductor between the inductor conductor and the substrate, eddy current generated on the substrate surface and stray capacitance generated between the inductor conductor and the substrate surface can be reduced.

According to the inductor element of the present invention, at least a part of the floating conductor is arranged to face the inductor conductor. Also in this case, occurrence of eddy current and stray capacitance is reduced.

According to a third aspect of the present invention, the floating conductor has a divided structure.

According to a fourth aspect of the present invention, a groove for dividing the floating conductor is provided, an electrode lead portion is formed inside the groove, and the electrode lead portion is electrically connected to the inductor conductor. Thereby, the inductor element has a two-layer metal structure.

According to a fifth aspect of the present invention, an inductor conductor and a floating conductor are formed on a substrate with an insulating layer interposed therebetween, and an electrode lead portion electrically connected to the inductor conductor is formed separately from the floating conductor. Thereby, the inductor element has a three-layer metal structure.

According to a sixth aspect of the present invention, at least one of the inductor conductor and the floating conductor has a spiral shape, and each spiral portion of the spiral is bent into an octagon. The octagonal folding facilitates the manufacture of the mask.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an inductance element to which the present invention is applied will be specifically described with reference to the drawings.

[First Embodiment] FIG. 1 is a plan view schematically showing an inductance element of the present embodiment formed on a substrate, and FIG. 2 is a diagram showing a simplified structure of the inductance element. The inductor element of the present embodiment includes an inductor conductor 1 and a floating conductor 2 having substantially the same shape.
It has a structure in which it is disposed on both upper and lower surfaces of an insulating layer to be described later. In FIG. 1, although the inductor conductor 1 shown by a solid line and the floating conductor 2 shown by a dotted line are shown in a shifted manner,
Actually, the inductor conductor 1 and the floating conductor 2 are formed so as to overlap as shown in FIG.

A semiconductor circuit (not shown) formed on the substrate 3 is connected to both ends of the inductor conductor 1, and a predetermined current flows through the inductor conductor 1 by the action of the semiconductor circuit. On the other hand, the floating conductor 2 is
Are formed in a floating structure so as not to be affected by a voltage change such as the above.

Inductor conductor 1 and floating conductor 2
Are formed in a spiral shape, and each orbital portion of the spiral is bent at an octagon. Thus, the reason why the shape of the inductor conductor 1 and the floating conductor 2 is octagonal is that it is easier to manufacture a mask than a case where the shape is a polygon or a circle having more than an octagon. This is because the square shape degrades the electrical characteristics of the inductor element.

As the substrate 3, for example, an n-type silicon substrate (n
-Si substrate) or another semiconductor substrate (for example, an amorphous material such as germanium or amorphous silicon) is used. Alternatively, a printed wiring board made of epoxy or the like may be used as the substrate 3. In addition, inductor conductor 1
Is formed of a metal thin film such as aluminum or gold, or a semiconductor material such as polysilicon.

On the substrate 3, in addition to the inductor element, an active element such as a transistor or a diode,
Although passive elements such as capacitors are mounted, FIG. 1 shows only inductor elements for simplicity of description.

FIG. 3 is an enlarged sectional view taken along line AA of FIG. As shown in FIG. 1, an insulating non-magnetic film 4 is formed on the surface of a substrate 3, and a spiral floating conductor 2 is formed on a part of the upper surface thereof. An insulating layer 5 is formed on the upper surfaces of the non-magnetic film 4 and the floating conductor 2, and a spiral inductor conductor 1 is formed on the upper surface.

FIG. 4A is an enlarged sectional view taken along the line BB of FIG. As shown in the figure, the structure on the lower surface side of the inductor conductor 1 is common to FIG. An electrode lead portion 1a is connected to one end of the inductor conductor 1, and the electrode lead portion 1a is formed on the upper surface of the inductor conductor 1 with the insulating layer 6 interposed therebetween. The electrode lead portion 1a is connected to another semiconductor circuit (not shown).

As described above, the inductor element shown in FIG. 1 has a structure in which the spiral-shaped inductor conductor 1 and the floating conductor 2 are disposed on the upper and lower surfaces of the insulating layer 5 so as to face each other. Since they are formed at intervals, eddy current generated on the substrate surface and stray capacitance generated between the substrate and the substrate surface can be reduced.

In FIG. 1, an example in which the spiral floating conductor 2 is formed on the substrate 3 has been described.
A floating conductor 2 'having a structure divided into a plurality of parts may be formed on the substrate 3 as shown in FIG.

FIG. 1 shows an example in which the number of revolutions of the spiral is three, but the number of revolutions is not limited to three, and may be substantially one as shown in FIG. It may be less than one round as shown in b). Further, the inductor conductor 1
The pattern width and pattern interval of the spiral pattern forming the floating conductor 2 need not be the same, and the pattern width and pattern interval may be different between the inductor conductor 1 and the floating conductor 2.

[Second Embodiment] The inductor element of the first embodiment has a three-layer metal structure depending on the location, whereas the inductor element of the second embodiment described below has only a two-layer metal structure. The feature is that it is formed by

FIG. 7 is a plan view schematically showing an inductor element according to the second embodiment. As shown in the figure, the inductor element of the second embodiment is composed of a spiral-shaped inductor conductor 11 and a floating conductor 12, and the floating conductor 12 has a groove P extending from the center of the spiral to the outer edge thereof. Is divided into a plurality of areas.

FIG. 8A is an enlarged sectional view taken along the line B'-B 'in FIG. 7, and FIG. 8B is an enlarged sectional view taken along the line CC in FIG. As shown in these drawings, a part of the electrode lead portion 11 a connected to one end of the inductor conductor 11 is formed inside the groove P of the floating conductor 12. That is, by forming the electrode lead portion 11a and the floating conductor 12 at the same height on the substrate 3, the entire inductor element can have a two-layer metal structure, and the manufacturing process can be simplified.

FIG. 9 is a view showing a modification of the second embodiment. FIG. 9 (a) is a plan view schematically showing an inductor element, and FIG. 9 (b) is a plan view of D in FIG. 9 (a). It is an expanded sectional view of the -D line. As shown in FIG.
A part of 1 'is formed inside the groove P, and an electrode lead portion 11'a is formed above the groove P. Since the electrode lead portion 11'a is formed at the same height as the inductor conductor 11 ', the entire inductor element can have a two-layer metal structure.

[Third Embodiment] In the first embodiment,
Although the inductor conductor 1 on the upper surface side and the inductor conductor 2 on the lower surface side of the insulating layer 5 have substantially the same shape, the shape does not need to be the same over the entire length of these inductor conductors, and only a part of them matches. Is also good.

FIG. 10 is a plan view schematically showing an inductor element according to the third embodiment. In the figure, the solid line is the inductor conductor 21 formed on the upper surface side of the insulating layer 5, and the dotted line is the floating conductor 22 formed on the lower surface side of the insulating layer 5.
Respectively. As shown in the figure, the floating conductor 22 has the same shape as a part of the inductor conductor 21, and those parts having the same shape are formed at positions facing each other with the insulating layer 5 interposed therebetween.

As described above, even when only a part of the shape of the inductor conductor 21 and the shape of the floating conductor 22 are the same, a partial two-layer structure is obtained.
The generation of eddy current and stray capacitance can be reduced.

[0029]

As described in detail above, according to the present invention, since the inductor conductor and the floating conductor having the same shape are arranged opposite to each other with the insulating layer interposed therebetween, the inductor conductor is spaced from the substrate. It is possible to reduce the eddy current generated on the substrate surface and the stray capacitance generated between the inductor conductor and the substrate surface, which are formed separately.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing an inductor element formed on a substrate.

FIG. 2 is a diagram showing a simplified structure of an inductor element.

FIG. 3 is an enlarged sectional view taken along line AA of FIG. 1;

FIG. 4 is an enlarged sectional view taken along line BB of FIG. 1;

FIG. 5 is a plan view schematically showing an inductor element having a floating conductor having a divided structure.

6A is a diagram illustrating an example in which the number of spiral turns is substantially one, and FIG. 6B is a diagram illustrating an example in which the number of spirals is less than one.

FIG. 7 is a plan view schematically showing an inductor element according to a second embodiment.

8A is an enlarged sectional view taken along line B′-B ′ of FIG.
FIG. 8B is an enlarged sectional view taken along line CC of FIG. 7.

FIGS. 9A and 9B are diagrams showing a modification of the second embodiment, in which FIG. 9A is a plan view schematically showing an inductor element, and FIG. 9B is an enlarged sectional view taken along line DD of FIG. 9A.

FIG. 10 is a plan view schematically showing an inductor element according to a third embodiment.

FIG. 11 is a diagram illustrating a magnetic flux generated from an inductor element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inductor conductor 2 Floating conductor 3 Substrate 4 Nonmagnetic film 5, 6 Insulating layer

Claims (6)

[Claims] 1. A spiral inductor conductor formed on a substrate, having a substantially same shape as the inductor conductor, disposed opposite to a lower surface of the inductor conductor via an insulating layer, and formed in a floating structure. An inductor element comprising: a floating conductor to be used. 2. A spiral-shaped inductor conductor formed on a substrate, formed on a lower surface side of the inductor conductor via an insulating layer, at least a part of the inductor conductor is opposed to the inductor conductor, and has a floating structure. An inductor element comprising: a floating conductor. 3. The inductor element according to claim 1, wherein the floating conductor is divided into a plurality of regions by grooves having a predetermined shape. 4. The device according to claim 3, further comprising an electrode lead portion having one end connected to the inductor conductor, wherein the inductor conductor, the floating conductor, and the electrode lead portion are formed in two layers on the substrate. And a part of the electrode lead portion or the inductor conductor is formed inside the groove. 5. The spiral-shaped inductor conductor formed on a substrate, wherein the spiral-shaped inductor conductor is formed on a lower surface side of the inductor conductor with an insulating layer interposed therebetween, and at least a part thereof is arranged to face the inductor conductor. An inductor element comprising: a floating conductor formed in a floating structure; and an electrode lead portion formed separately from the floating conductor and electrically connected to the inductor conductor. 6. The inductor element according to claim 1, wherein at least one of the inductor conductor and the floating conductor is formed in a spiral shape in which each orbital portion is bent in an octagon.