JP3419525B2 - LC element and semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LC element and a semiconductor device which can be incorporated in a semiconductor device or the like or can attenuate a predetermined frequency band by itself.

[0002]

2. Description of the Related Art With the development of electronic technology in recent years, electronic circuits have been widely used in various fields. Therefore, it is desirable to operate these electronic circuits stably and reliably without being affected by the outside. Be done.

However, noise enters the electronic circuit directly or indirectly from the outside. For this reason,
There is a problem that various electronic devices using electronic circuits often cause malfunctions.

In particular, electronic circuits often use a switching regulator as a DC power source. Therefore, a large amount of noise having various frequency components is often generated in the power supply line of the switching regulator due to a transient current such as switching or due to a load change caused by the switching operation of the digital IC used. Then, these noises are propagated to other circuits in the same device through the power supply line or by radiation to cause malfunction or S / S.
This may have a bad effect such as a decrease in N ratio, and may cause malfunction of other electronic devices that are being used even closer.

In order to remove such noise, various noise filters are generally used in electronic circuits.
In particular, since many electronic devices with various configurations are used in recent years, regulations on noise have become more and more stringent, and as a small, high-performance noise filter that can reliably remove generated noise. Development of a functional LC element is desired.

As one of such LC elements, the LC noise filter disclosed in Japanese Patent Laid-Open No. 3-259608 is known. This LC noise filter has an L component and a C component in a distributed constant, and can obtain good attenuation characteristics over a relatively wide band as compared with a lumped constant type LC noise filter. is there.

[0007]

By the way, the above-mentioned L
The C noise filter is manufactured by forming a capacitor conductor on one surface of an insulating sheet and an inductor conductor on the other surface, and then folding the insulating sheet. However, there is a problem that the manufacturing process becomes complicated because such processes are required.

Also, this LC noise filter is used as an IC or L
When the SI power supply line or the signal line is directly inserted and used, the LC noise filter and the IC or the like must be wired, and there is a problem that it takes time to assemble the components.

Further, since this LC noise filter is formed as a single component, there is a problem that it is almost impossible to include it in an IC or LSI circuit, that is, to insert it in an internal conduit of the IC or LSI. there were.

Further, the capacitance formed in a distributed constant in this LC noise filter is determined by the shapes and arrangements of the inductor conductor and the capacitor conductor, so that the capacitance is constant after the parts are completed. Therefore, there is a problem that the characteristics as a whole are fixed and there is no versatility. For example, when it is desired to change the capacitance, it is necessary to change the shape of the conductor for the inductor or the conductor for the capacitor, and it is difficult to arbitrarily change and use the capacitance in the incorporated circuit. .

Therefore, the present invention was created in view of the above-mentioned points, and its purpose is to simplify the manufacturing process and to eliminate the work of assembling parts in the subsequent steps, and further to realize the IC and LSI. An object is to provide an LC element and a semiconductor device that can be formed as a part.

Another object of the present invention is to provide an LC element and a semiconductor device capable of changing the capacitance existing in a distributed constant.

[0013]

Means for Solving the Problems (1) In order to solve the above-mentioned problems, an LC element of the present invention has an n region or p region.
With respect to the semiconductor substrate on which one of the regions is formed on the front surface side, the spiral-shaped first electrode formed on the semiconductor substrate, and the spiral-shaped first electrode,
Formed between a spirally-shaped second electrode that is substantially concentrically adjacent to each other in the same plane, at least one of the spirally-shaped first and second electrodes, and the semiconductor substrate. And a capacitor formed between the inductor formed by each of the spirally shaped first electrode and the second electrode, and the capacitor formed between them. At least one of the first electrode and the second electrode having a shape is used as a signal input / output path.

(2) In the LC element of the present invention , the spiral first electrode formed on one surface side of the semiconductor substrate and the spiral first electrode formed on the other surface side of the semiconductor substrate. A second spiral-shaped electrode formed at a position substantially opposite to the first electrode, and an insulating layer formed between at least one of the first and second spiral-shaped electrodes and the semiconductor substrate, And the inductor formed by each of the spiral-shaped first electrode and the second electrode and the capacitor formed between them are distributed constant, and the spiral-shaped first electrode is formed. At least one of the electrode and the second electrode is used as a signal input / output path.

[0015] (3) LC element of the present invention, the above (1),
In the LC element of (2), the carrier is injected in advance at a position corresponding to the spirally shaped first electrode on the surface of the semiconductor substrate.

(4) The LC element of the present invention is the same as the above (1) to
In the LC element according to any one of (3) , the length of the second electrode is set longer or shorter than that of the first electrode having a spiral shape, so that the first and second electrodes are formed.
It is characterized by partially corresponding the electrodes of.

[0017] (5) LC element of the present invention, the above (1),
In the LC element according to any one of (3) and (4) , an inversion layer including a spiral n region or p region is formed along the spiral first and second electrodes instead of the semiconductor substrate. It is characterized in that the semiconductor substrate is used.

(6) The LC element of the present invention is the same as the above (2) to
In the LC element according to any one of (4) , instead of the semiconductor substrate, an inversion layer composed of a spiral n region or p region is formed between respective spiraling portions of the spiral first and second electrodes. It is characterized in that the semiconductor substrate is used.

(7) The LC element of the present invention has the above (1) to
In the LC element according to any one of (6) , one of the first and second spiral electrodes is divided into a plurality of pieces, and a part of each of the divided plurality of electrode pieces is electrically connected. It is characterized by

(8) The LC element of the present invention has the above (1) to
In the LC element according to any one of (6) , the first and second input / output electrodes electrically connected to each of the spiral-shaped first and second electrodes near both ends thereof, respectively, and the spiral-shaped A ground electrode electrically connected to one end of the other of the first and second electrodes, and a signal is input from any one of the first and second input / output electrodes, and the other And a signal is output from the ground electrode, and the ground electrode is connected to or grounded to a power source having a fixed potential.

(9) The LC element of the present invention has the above (1) to
In any one of (6) , the first and second input / output electrodes electrically connected to each of the spiral-shaped first and second electrodes near both ends thereof, respectively, and the spiral-shaped first and second input / output electrodes. And third and fourth input / output electrodes electrically connected to the other ends of the second electrode, respectively, and
And is used as a common mode type element in which both the first electrode and the second electrode having a spiral shape are used as signal input / output paths.

(10) The LC element according to the present invention has the above (1)
In any one of (9) to (9) , the voltage applied to each of the spiral-shaped first electrode and the second electrode is variably set, so that the spiral-shaped first electrode or the spiral-shaped first electrode It is characterized in that a spiral inversion region is generated at a position corresponding to at least one of the second electrodes on the surface of the semiconductor substrate, or the generated inversion region is eliminated.

[0023] (11) A semiconductor device of the present invention, the
The LC element according to any one of (1) to (10) is formed as a part of a substrate, and at least one of the spiral first electrode and the second electrode is inserted into a signal line or a power supply line to be integrated. It is characterized by being molded.

(12) The LC element of the present invention has the above (1)
In any of the LC elements of (7) to (7), an insulating film is formed on the entire surface by a chemical liquid phase method, a part of the insulating film is removed by etching or laser light irradiation to form a hole, and the hole is soldered. It is characterized in that terminals are attached by sealing it to the extent that it rises on the surface.

(13) The LC element of the present invention has the above (1)
In any one of (7) to (7) , at least one of the spirally shaped first and second electrodes is provided with a protection circuit for bypassing an overvoltage to the operating power supply line side or the ground side.

[0026]

In the LC element of the above (1) , the spiral first and second electrodes are formed on the surface side of the semiconductor substrate so as to be substantially concentric, that is, to circulate substantially in parallel. An insulating layer is formed between at least one of these two electrodes and the semiconductor substrate, and an MO including the first or second electrode, the insulating layer and the semiconductor substrate is formed.
It has an S structure.

LC of the above (1) having such a structure
In the element, each of the spiral-shaped first and second electrodes functions as an inductor, and each of the first and second electrodes is directly connected to the semiconductor substrate or indirectly through an insulating layer. As a result, a capacitor is formed between the first and second electrodes as a distributed constant in the spiral direction.

Therefore, when the signal input to one end of the spirally shaped first or second electrode is propagated through the inductor and the capacitor existing in a distributed constant, a good attenuation characteristic is obtained over a wide band. Is obtained.

In particular, the LC element of the above (1) can be manufactured by forming the insulating layer and the first and second spiral electrodes on the surface of the semiconductor substrate, and the manufacturing is very easy. Further, since this LC element is formed on a semiconductor substrate, it can be formed as a part of an IC or an LSI. Assembly work can be omitted.

Further, in the LC element of (2) above , each of the above-mentioned spiral-shaped first and second electrodes is arranged substantially opposite to each other with the semiconductor substrate interposed therebetween, and each of these electrodes serves as an inductor conductor. The point that a capacitor is formed in a distributed constant manner between these electrodes while functioning is described above.
It can be considered in exactly the same manner as the LC element of (1) . Therefore, according to the LC element of the above (2) , it is possible to have good attenuation characteristics over a wide band, to facilitate manufacturing, and to form the LC element as a part of the substrate.

Further, in the above-mentioned (3) LC element, carriers are preliminarily injected into the position corresponding to the first electrode.
In general, the above-described LC elements (1) and (2) have a MOS structure, and therefore, when a predetermined voltage is applied to the first or second electrode functioning as a gate, the LC element is applied to the surface of the semiconductor substrate. An inversion region is generated, and a depletion layer is formed around this inversion region. Therefore, although the value of the capacitance formed between the first and second electrodes changes depending on the presence or absence of the inversion region and the depletion layer, by injecting carriers into the surface of the semiconductor substrate in advance,
The characteristics of the LC element can be changed by shifting the timing of forming the inversion region and the depletion layer.

Further, in the LC element of the above (4) , one of the first and second electrodes is formed to be short, and even in this case, similarly, the first and second electrodes having different lengths are formed.
Each of these electrodes functions as an inductor, and a capacitor formed with a semiconductor substrate and an insulating layer sandwiched between these electrodes exists in a distributed constant manner. Therefore, this LC
The device has an effect that it has a good attenuation characteristic over a wide band, is easy to manufacture, and can be formed as a part of a substrate.

Further, in the LC element of the above (5) , each of the above-mentioned LC elements (excluding the LC element of the above (2) ) is formed using a single layer composed of the n region or the p region. On the other hand, it is different in that a semiconductor substrate in which an inversion layer of an n region or a p region which is a spiral inversion layer is formed along the first and second electrodes is used. That is, in this case, the first and second electrodes having different numbers of turns are connected to each other via the npn structure or the pnp structure in the semiconductor substrate, and good isolation can be performed. Therefore, one formed in parallel
It is possible to easily form a state in which a capacitor is formed in a distributed constant only between the first and second electrodes of the set, and this LC element can have good attenuation characteristics over a wide band.

Further, in the LC element of the above (6) , as compared with the above-mentioned LC elements (excluding the LC element of the above (1)) , in the semiconductor substrate, between the first electrodes and between the second electrodes. The difference is that an inversion layer is formed between them. That is, by forming this inversion layer, the npn structure or p is formed in the radial direction of the spiral first and second electrodes.
Since it has the np structure, it is possible to perform good isolation between the lapped portions in the semiconductor substrate corresponding to the first and second electrodes. Therefore, it is possible to easily form a state in which the capacitor is formed in a distributed constant manner only between the pair of first and second electrodes arranged to face each other,
This LC element can have good attenuation characteristics over a wide band.

In the LC element of (7) , the first or second electrode is divided into a plurality of electrode pieces, and a part of each of the electrode pieces is electrically connected for use. In this case, the self-inductance of each electrode piece becomes small, and the distributed constant type LC element is less affected by the self-inductance of each electrode piece.

Further, in the LC element of the above (8) , the first and second input / output electrodes connected to both ends of one of the first and second electrodes are provided, and the first and second input / output electrodes are provided. By providing a ground electrode near one end of the other of the second electrodes, a three-terminal type LC element in which one spiral electrode is used as a signal input / output path can be easily formed.

Further, in the LC element of (9) , third and fourth input / output electrodes are provided near both ends of the other of the first and second electrodes described above, and the spiral-shaped 2 Both of the two electrodes are used as signal input / output paths 4
A terminal common mode type LC element can be easily formed.

In the LC element of (10) above , the first
By variably setting the voltage applied to the second electrode, that is, by changing the potential difference between these two electrodes, an inversion region is generated on the surface of the semiconductor substrate, or the generated inversion region is eliminated. . As described above, since the depletion layer is formed on the outer periphery of the inversion region, the capacitance between the two spiral electrodes changes depending on whether or not the inversion region is generated. Can be switched.

Further, in the semiconductor device of (11) , the LC elements of (1) to (10) described above are formed on a part of the substrate so as to be inserted into the signal line or the power supply line. As a result, it can be manufactured integrally with other components on the semiconductor substrate, which facilitates the manufacturing and eliminates the work of assembling the components in the subsequent process.

Further, in the LC element of (12) , an insulating film is formed on the entire surface by the chemical liquid phase method after the LC element of any of (1) to (7) described above is formed on a semiconductor substrate. To do. After that, a hole is formed in a part of the insulating film by etching or laser light irradiation, and solder is put in the hole to attach a terminal. Therefore, surface mount type LC
The element can be easily manufactured, and the surface mounting type also facilitates the assembling work of this LC element.

In the LC element of (13) above , the first
A protection circuit is connected to at least one of the second electrode and the second electrode, and when an overvoltage is applied to these electrodes, a bypass current flows to the operation power supply line side or the housing ground side, and the first and second electrodes are connected. It is possible to prevent dielectric breakdown between the electrode and the semiconductor substrate.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An LC device of an embodiment to which the present invention is applied will be specifically described below with reference to the drawings.

First Embodiment FIG. 1 is a plan view of an LC device of the first embodiment to which the present invention is applied. 2 is an enlarged sectional view taken along the line AA of FIG. 1, FIG. 3 is an enlarged sectional view taken along the line BB of FIG. 1, FIG. 4 is an enlarged sectional view taken along the line CC of FIG. 1, and FIG. It is a DD line expanded sectional view.

As shown in these figures, the LC of this embodiment is
The device 100 is a p-type silicon substrate (p
The first electrode 10 and the second electrode 26 are formed on one surface side of the -Si substrate 30 and the insulating layer 28 is formed on one surface side of the p-Si substrate 30.

Each of the first and second electrodes 10 and 26 is formed, for example, by depositing a thin film of aluminum, copper or gold, or by heavily doping P by diffusion or ion implantation.

The insulating layer 28 serves to insulate the p-Si substrate 30 from the first electrode 10 on the surface of the p-Si substrate 30. As shown in FIG. 2A, the entire surface of the p-Si substrate 30 excluding the second electrode 26 is covered with this insulating layer 28 (or the first electrode 1).
The insulating layer 28 may be formed only in the portion corresponding to 0), and the first electrode 10 described above is formed on the surface of the insulating layer 28. The insulating layer 28 is formed of, for example, P ₂ -added SiO ₂ (P-glass).

The second electrode 26 is formed substantially concentrically and substantially in parallel with the above-mentioned first electrode 10. By applying a predetermined voltage between the second electrode 26 and the first electrode 10, the n-type inversion region 22 is formed on the surface of the p-Si substrate 30 facing the first electrode 10. It has become so.

In addition, the above-mentioned first electrode 10 and second electrode
As shown in FIGS. 1, 3 and 4, the ground electrode 16 and the input / output electrodes 18 and 20 are connected to each of the electrodes 26 of FIG.

As described above, the LC element 10 of this embodiment
0 is the first electrode 10, the insulating layer 28, and the p-Si substrate 30.
Assuming that the first electrode 10 has a MOS structure or a MIS structure and is an enhancement type structure in which carriers are not injected in advance on the surface of the p-Si substrate 30, The inversion region 22 is formed only when the voltage of 1 is applied.

FIGS. 2A and 2B are views showing a state in which the inversion region is formed. The input / output electrode 1 connected to the first electrode 10, that is, connected to the first electrode 10.
In the state where a predetermined positive voltage (positive voltage with respect to the voltage applied to the ground electrode 16) is not applied to 8 and 20, the inversion region is formed on the surface of the p-Si substrate 30 as shown in FIG. 22 does not appear.

However, when a predetermined positive voltage is applied to the first electrode 10, as shown in FIG. 2B, an n region is formed near the surface of the p-Si substrate 30 corresponding to the first electrode 10. The inversion area 22 consisting of appears. Further, inside the p-Si substrate 30 and outside the inversion region 22, a depletion layer 32 in which holes are eliminated by the positive voltage applied to the first electrode 10 is formed. Therefore, the inversion area 2
When 2 appears, the electrons in the inversion region 22 and the holes in the p-Si substrate 30 are arranged to face each other with the depletion layer 32 sandwiched therebetween, and a capacitor is formed. Moreover, since this capacitor is formed over substantially the entire length of the first electrode 10, the second electrode 26 connected to the p-Si substrate 30 is formed.
A capacitor is formed between the first electrode 10 and the first electrode 10 in a distributed constant manner, and the capacitor formed with the insulating layer 28 interposed and the capacitor formed with the depletion layer 32 interposed are connected in series. become.

FIG. 6 is a diagram showing an equivalent circuit of the LC device 100 of the first embodiment. The equivalent circuit shown in FIG.
It is a circuit corresponding to FIG. 2A, and is a second circuit directly connected to the p-Si substrate 30 between the first electrode 10 and the p-Si substrate 30 which are arranged with the insulating layer 28 interposed therebetween. It is shown that a capacitor is formed between the electrode 26 and the first electrode 10.

Since the p-Si substrate 30 generally has a large specific resistance, the number of circuit cycles is greater than the capacitance of the capacitor formed between the first electrode 10 and the second electrode 26 arranged closest to each other. The capacitance of the capacitor formed between the first electrode 10 and the second electrode 26 having different values is extremely small. Therefore, the capacitors are formed in a distributed constant manner only between the pair of electrodes 10 and 26 arranged adjacent to each other.

The circuit shown in FIG. 9A shows the case where the first electrode 10 is used as a signal input / output path and the ground electrode 16 is grounded, which functions as a three-terminal type element. To do.

In this case, the first electrode 10 functions as an inductor conductor having the inductance L1, and the second electrode 26 functions as an inductor conductor having the inductance L2. Also, as mentioned above,
A capacitor having a predetermined capacitance C is formed in a distributed constant manner between these two inductor conductors (between the first and second electrodes). Therefore, this LC device 1
00 is capable of exerting an excellent attenuation characteristic which is not present in the conventional lumped element type element, and only a predetermined frequency component is removed from the signal input from one of the input / output electrodes 18 and 20, and the other is output from the other. It will be output.

Although FIG. 9A shows the case where the earth electrode 16 is grounded, the earth electrode 16 may be connected to a power source having a predetermined potential.

FIG. 6B shows an equivalent circuit when the variable bias circuit 12 for applying a variable bias voltage is connected between the input / output electrode 18 and the ground electrode 16. As described above, the inversion region 22 and the depletion layer 32 appear on the surface of the p-Si substrate 30 when a predetermined positive voltage is applied to the first electrode 10 side. Therefore, as shown in FIG. 2B, the capacitor formed with the insulating layer 28 sandwiched therebetween and the capacitor formed with the depletion layer 32 sandwiched are connected in series. The capacitance C of the capacitor formed in a distributed constant becomes smaller than that shown in FIG.

Therefore, by switching the bias voltage applied by the variable bias circuit 12,
The capacitance C formed in a distributed constant manner between the electrode 10 and the second electrode 26 also changes, and the attenuation characteristic of the LC element 100 changes as a whole.

In FIG. 6B, the variable bias circuit 1
Although the case where the voltage level applied to the first electrode 10 is set higher than that of the second electrode 26 by adding 2 has been described, the variable bias circuit 12 is not added and the input / output electrode 18 is added. The average voltage level itself of the signal input to the terminal may be kept higher than the voltage applied to the ground electrode 16.

Next, the manufacturing process of the LC device 100 of this embodiment will be described.

(1) Formation of oxide film: First, the surface of the p-Si substrate 30 is thermally oxidized to form an oxide film (SiO ₂ ).

(2) Removal of the part corresponding to the first electrode: Next, the opening is formed by removing the oxide film in the part where the first electrode 10 is to be formed. In the case of the LC element 100 of the present embodiment, since the first electrode 10 needs to be formed in a spiral shape, this opening is also formed so as to have a spiral shape. In this way, the portion of the p-Si substrate 30 corresponding to the first electrode 10 is exposed.

(3) Formation of Oxide Film: Next, the p-Si substrate 3 partially exposed in this way
A new oxide film, that is, an insulating layer 28 is formed for 0.

(4) Formation of first electrode and other electrodes: Next, the first electrode 10 is formed by vapor deposition of aluminum, for example, and the input / output electrode 18 connected to this first electrode is formed. , 20 are formed.

The second electrode 2 is formed before or after the steps (2) to (4) or in parallel with the steps (2) to (4).
The second electrode 2 is opened by opening a window corresponding to
6 and the ground electrode 16 connected thereto are formed.

(5) Formation of insulating layer: Finally, P-glass is attached to the entire surface and then heated to form a smooth surface.

The process of manufacturing the LC element 100 in this manner is basically similar to the process of manufacturing a normal MOS • FET, or is a simplified process of manufacturing a normal MOS • FET. Is. Therefore, the manufacturing itself can be dealt with by changing the shape of the photomask or by partially changing the order of the steps for manufacturing a general MOS • FET.
It can be formed on the same substrate as the FET and the bipolar transistor. Therefore, it can be formed as a part of an IC or LSI, and when it is formed as a part of these parts, the work of assembling the parts in the subsequent process can be omitted.

In this way, the LC device 100 of this embodiment is
Each of the first electrode 10 and the second electrode 26 forms an inductor, and
A capacitor is formed between the second electrode 26 and the second electrode 26 in a distributed constant manner. Therefore, when the ground electrode 16 provided at one end of the second electrode 26 is connected to the ground or a fixed potential and the first electrode 10 is used as a signal input / output path, the input signal On the other hand, the LC element has a good attenuation characteristic in a wide band.

Further, as described above, this LC device 100
Can be manufactured by applying general MOS / FET manufacturing techniques, and is therefore easy to manufacture and suitable for miniaturization. In addition, when the LC element is manufactured as a part of the semiconductor substrate, wiring with other components can be performed at the same time, which eliminates the need for assembling work in the subsequent process.

In addition, the LC element 100 of this embodiment is the first
By changing the bias voltage applied to the electrode 10 of the first electrode 10 to generate the inversion region 22 at a position facing the first electrode 10 or extinguishing the generated inversion region 22, the first electrode 10 and the It is possible to switch the capacitance of the capacitor formed between the second electrode 26 and the second electrode 26 in a distributed constant manner, and to adjust or change the overall frequency characteristics of the LC element 100.

Although the first electrode 10 is used as a signal input / output path in the above-described first embodiment, the second electrode 26 is used.
May be used as a signal input / output path. That is, as shown in FIG. 7, by connecting the input / output electrodes 18 and 20 to both ends of the second electrode 26, the second electrode 26 is used as a signal input / output path, and at the same time the first electrode 10 is connected. The ground electrode 16 is connected to one end, and the ground electrode 16 is grounded or connected to a fixed potential. In this case, the inversion region 22 is formed at a position facing the first electrode 10 connected to the ground or the fixed potential, but two inversion regions 22 are formed as shown in FIG. 6B. The same applies to the fact that the capacitors are connected in series and the frequency characteristics of the LC element 100 as a whole can be changed by changing the relative potentials of the input / output electrode 18 and the ground electrode 16.

In FIG. 8, the second electrode 26 is formed on the p-Si substrate 3
It is a figure which shows the modification at the time of arrange | positioning so that it may oppose the 1st electrode 10 on the surface (back surface) opposite to 0. Also,
FIG. 9 is a view showing an enlarged cross section taken along the line AA of FIG. 8 and corresponds to FIG. FIG. 10 shows that by connecting the input / output electrodes 18 and 20 to both ends of the second electrode 26,
FIG. 11 is a diagram showing a modification example in which the electrode 26 of FIG. 4 is used as a signal input / output path, the ground electrode 16 is connected to one end of the first electrode 10, and the ground electrode 16 is grounded or connected to a fixed potential. , Which corresponds to FIG.

Thus, the two spiral electrodes 1
Even when 0 and 26 are arranged so as to face each other, as in the LC element 100 shown in FIG.
Each of the second electrode 10 and the second electrode 26 functions as an inductor, and a capacitor is formed between them in a distributed constant manner, which has good frequency characteristics and is easy to manufacture. It will be.

Second Embodiment Next, an LC device according to a second embodiment of the present invention will be specifically described with reference to the drawings.

The LC element 100 of the first embodiment described above is
The first electrode 10 and the second electrode 26 are formed in parallel over substantially the entire length, that is, in substantially the same length. The LC element 200 of the present embodiment is the same as that shown in FIG. The feature is that the second electrode 26 is shortened by about one turn.

FIG. 11 shows an LC device 200 of the second embodiment.
FIG. As shown in FIG. 11, the second electrode 26
Even if a part of the first electrode is omitted, each inductor formed by the shortened second electrode 26 and the first electrode 10 longer than that, and the first electrode 10 and the second electrode Since the capacitors formed by 26 and 26 are formed in a distributed constant manner, the LC element 1 of the first embodiment shown in FIG.
As with 00, it has a good attenuation characteristic.

FIG. 12 is a diagram showing an equivalent circuit of the LC element 200 of this embodiment. As shown in the figure, the inductance L3 is reduced by the number of turns of the second electrode 26 which is reduced.
Becomes smaller, and correspondingly, the capacitance C1 existing in a distributed constant also becomes smaller.

By changing the voltage applied to the first electrode 10 (bias voltage applied to the input / output electrode 18), the voltage between the first electrode 10 and the second electrode 26 having a reduced number of turns is changed. The formed capacitance also changes and LC
The point that the attenuation characteristic of the element 200 can be variably controlled is the same as the LC element 100 of the first embodiment described above.

As described above, the LC device 200 of this embodiment is used.
Is a first electrode 10 and a second electrode shorter than the first electrode 10.
An inductor and a capacitor are formed in a distributed constant manner by the electrode 26 of, and can function as an element having a good attenuation characteristic.

In addition, the LC element 200 can be manufactured by utilizing the semiconductor manufacturing technology, and can be formed as a part of LSI or the like, and in this case, the wiring process in the subsequent process can be omitted. The fact that the frequency characteristic can be changed by changing the relative voltage applied to the electrode 10 of is similar to the LC element 100 of the first embodiment described above.

The LC element 200 of this embodiment is the first
Although the electrode 10 is used as a signal input / output path, the second electrode 26 may be used as a signal input / output path and the first electrode 10 side may be connected to ground or a fixed potential.

FIG. 13 is a diagram showing a modified example in which the second electrode 26 is used as a signal input / output path, and corresponds to FIG. 7 of the first embodiment. In this case, the input / output electrodes 18 and 20 are connected to both ends of the second electrode 26, and the ground electrode 16 is connected to one end of the first electrode 10.

Even in such a case, the short first electrode 10 and the long second electrode 26 each function as an inductor, and a capacitor is formed between them in a distributed constant manner. LC device 200 shown in FIG.
Good damping characteristics can be obtained as well.

FIG. 14 is a diagram showing a modified example in which the second electrode 26 is arranged on the opposite surface side of the p-Si substrate 30 so as to substantially face the first electrode 10. In addition, FIG.
Uses the second electrode 26 as a signal input / output path by connecting the input / output electrodes 18 and 20 to both ends of the second electrode 26, and connects the ground electrode 16 to one end of the first electrode 10. Then, it is a diagram showing a modified example in the case of connecting the ground electrode 16 to the ground or to a fixed potential.

In this way, the spiral shape is different in length 2
Even when the two electrodes 10 and 26 are arranged so as to face each other, the LC device 200 shown in FIG.
Similarly, each of the first and second electrodes 10 and 26 functions as an inductor, and a capacitor is formed between them in a distributed constant manner, which has good frequency characteristics and is manufactured. It has advantages such as ease.

Third Embodiment Next, regarding the LC device 300 of the third embodiment of the present invention,
A specific description will be given with reference to the drawings.

The LC element 100 of the first embodiment and the LC element 200 of the second embodiment described above function as a three-terminal normal mode type element.
The C element 300 is characterized in that it is formed so as to function as a 4-terminal common mode element.

FIG. 16 is a plan view of the LC device of the third embodiment. As shown in the figure, the LC device 30 of the third embodiment
0 is provided with input / output electrodes 36 and 38 at both ends of the second electrode 26, and this point shows that the LC element 100 shown in FIG.
Is different from

FIG. 17 is a diagram showing an equivalent circuit of the LC element of the third embodiment. As shown in the figure, the first electrode 10 formed between the two input / output electrodes 18 and 20 functions as an inductor having the inductance L1 and is formed between the two input / output electrodes 36 and 38. The second electrode 26 functions as an inductor having the inductance L2. Moreover, these first and second electrodes 1
0 and 26 are respectively used as signal input / output paths, and capacitors having a capacitance C are formed between them in a distributed constant manner as in the LC element 100 of the first embodiment.

As described above, the LC device 300 of this embodiment is used.
By providing the two input / output electrodes 36 and 38 at both ends of the second electrode 26 as well as the first electrode 10, it is possible to function as a four-terminal common mode element having good attenuation characteristics. it can. Further, the bias voltage applied between the input / output electrodes 18 and 36 or the average voltage difference between the signals input to the input / output electrodes 18 and 36 is changed to form a distributed constant between the first electrode 10 and the second electrode 26. It is possible to change the capacitance C of the capacitor to
It is possible to variably control the damping characteristic of the entire 00.

FIG. 18 is a diagram showing a modified example in which the second electrode 26 is arranged on the opposite surface side of the p-Si substrate 30 so as to substantially face the first electrode 10.

As described above, the two spiral electrodes 1
Even when 0 and 26 are arranged so as to face each other, as in the LC device 300 shown in FIG.
Each of the electrodes 10 and 26 functions as an inductor, and a 4-terminal common-mode element in which a capacitor is formed between them in a distributed constant manner can be formed, and has advantages of good frequency characteristics and easy manufacture. Will have.

Fourth Embodiment Next, an LC device according to a fourth embodiment of the present invention will be specifically described with reference to the drawings.

The LC devices 100 and 20 of the above-mentioned respective embodiments
In each of 0 and 300, the second electrode 26 was formed of one conductor, but in the LC element 400 of this embodiment, the second electrode 26 is divided into a plurality of (for example, three) divided electrode pieces. 26
It is characterized in that it is divided into -1, 26-2, 26-3.

FIG. 19 is a plan view of the LC element of the fourth embodiment. As shown in the figure, the LC device 40 of the fourth embodiment
0 indicates that the second electrode 26 used in the LC element 100 shown in FIG. 1 is divided into three divided electrode pieces 26-1, 26-2,
26-3 has the structure replaced. These divided electrode pieces 26-1 to 26-having a spiral shape as a whole
A ground electrode 16 is connected to each of the 3
By grounding one ground electrode 16, a part of the inductor formed by each of the divided electrode pieces 26-1 to 26-3 is grounded. Alternatively, by connecting the three ground electrodes 16 to a power source having a fixed potential, a part of the inductor formed by each of the divided electrode pieces 26-1 to 26-3 becomes the fixed potential.

FIG. 20 is a diagram showing an equivalent circuit of the LC element 400 of the fourth embodiment. As shown in the figure, the entire first electrode 10 functions as an inductor having an inductance L1, and each of the divided electrode pieces 26-1, 26
-2 and 26-3 are inductances L3 and L, respectively
4 and L5 function as an inductor. And
The first electrode 10 and the divided electrode pieces 26-1 to 26-3 function as capacitors having capacitors C2, C3, C4, and these capacitors are formed in a distributed constant manner.

In the LC element 400 of this embodiment, the self-inductances L3, L4 and L5 of the divided electrode pieces 26-1, 26-2 and 26-3 are small. Therefore, the influence of these self-inductances on the characteristics of the LC element 400 as a whole becomes small, and the capacitance L formed with the inductance L1 of the first electrode 10 in a distributed constant manner.
2, C3 and C4 determine the characteristics of the LC element 400 as a whole.

The bias voltage applied between the input / output electrode 18 and the ground electrode 16, or the input / output electrode 18
By changing the average voltage level of the signal input to
The capacitances C2 and C3 of the capacitors formed in a distributed constant manner between the first electrode 10 and the divided electrode pieces 26-1 and 26-2 can be changed, and the attenuation characteristic of the LC element 400 as a whole can be changed. Can be controlled.

In the LC element 400 of the present embodiment whose planar structure is shown in FIG. 19, the first electrode 10 is used as a signal input / output path and the second electrode 26 is divided into three parts.
On the contrary, the second electrode 26 may be used as a signal input / output path and the first electrode 10 side may be divided into a plurality of parts. In this case, the ground electrode 16 is connected to each of the plurality of divided first electrodes 10, and the input / output electrodes 18, 20 are provided near both ends of the second electrode 26.
Should be connected.

FIG. 21 shows three divided electrode pieces 26-1 and 26-2.
It is a figure which shows the modification when 6-2 and 26-3 are arrange | positioned so that it may oppose the 1st electrode 10 in the surface side opposite to the p-Si substrate 30 substantially.

Thus, the spirally shaped first electrode 10
And the three divided electrode pieces 26-1, 26-2, and 26-3 are arranged so as to face each other, as in the LC element 400 shown in FIG. Each of the divided electrode pieces 26-1, 26-2, and 26-3 functions as an inductor, and a capacitor is formed between them in a distributed constant manner, which has good frequency characteristics. It has advantages such as easy manufacturing.

Other Examples Next, LC elements according to other examples of the present invention will be specifically described with reference to the drawings.

22 and 23 are schematic views showing a case where terminals are attached using the chemical liquid phase method. FIG. 22
2 is a plan view of the LC element 500 of this embodiment corresponding to FIG. 1 and the like. As shown in the figure, the first electrode 10 and the second electrode 26 of the LC element 500 have ground electrodes at both ends or one end. 16 and the input / output electrodes 18 and 20 are not provided.

A single LC element 50 is a semiconductor substrate including the first and second electrodes 10 and 26 having such a shape.
After cutting every 0, a silicon oxide film 40 is formed as an insulating film on the entire surface of the individually cut chips (elements) by a chemical liquid phase method, as shown in the cross section taken along line EE of FIG. To do. After that, the silicon oxide film 40 on one end of the first and second electrodes 10 and 26 is etched.
Is removed to form a hole, and the hole is sealed with solder 42 to the extent that it rises on the surface, so that the protruding solder 42 can be brought into direct contact with the land or the like of the printed wiring board. Therefore, it is convenient for surface mounting.

Incidentally, another insulating material such as synthetic resin may be used for the protective film on the element surface, and a laser beam may be used for perforating the protective film. Further, as shown in FIG. 23, the height of the protruding solder 42 becomes substantially the same by adjusting the film thickness of each electrode so that the first electrode 10 and the second electrode 26 have the same height. , Which is more convenient for surface mounting.

FIG. 24 shows the LC element 1 of each of the above-mentioned embodiments.
It is explanatory drawing at the time of forming 00 etc. as a part of LSI etc. As shown in the figure, each of the LC elements 1 described above is connected to a line 48 for various signals or power on the semiconductor chip 46.
Incorporate by inserting 00 etc. In particular, the LC element 100 and the like of each of the above-described embodiments can be manufactured at the same time in the process of forming various circuits on the semiconductor chip 46, so that there is an advantage that the wiring process and the like in the subsequent process are unnecessary.

Next, an example of using the above-mentioned LC element as a part of an actual circuit will be described.

For example, the above-mentioned first and second electrodes 1
When the line width of each of 0 and 26 is reduced in consideration of miniaturization and the like, the resistance becomes high and the signal level is attenuated between the input / output electrodes 18 and 20. Therefore, the LC element 100 is actually
When using, etc. as a part of the circuit, a practical configuration can be obtained by connecting a buffer with high input impedance to the output side.

FIG. 25 is a diagram showing an example in which a buffer is connected to the output side. FIG. 1A shows a MOS as a buffer.
-The case where the source follower circuit 50 which consists of FET and resistance is used is shown. The MOS • FET which constitutes the source follower circuit 50 is the LC element 10 of each of the above-mentioned embodiments.
Since it has the same MOS structure as 0 or the like, the whole including the source follower circuit 50 can be integrally formed as an LC element.

Further, FIG. 10B shows a case where an emitter follower circuit 52 composed of two bipolar transistors and a resistor is used as a buffer. Since the bipolar transistor can be formed by using the p-Si substrate 30 that constitutes the LC element 100 or the like, the entire body including the emitter follower circuit 52 can be integrally formed as an LC element.

By providing the buffer on the output side in this way, the signal level attenuated by the inductor portion (the first electrode 10 or the second electrode 26) of the LC element 100 or the like is restored by amplification, and the SN ratio is increased. It becomes possible to obtain a good output signal.

FIG. 26 is a diagram showing an example in which a level conversion circuit is connected to the output side. FIG. 1A shows a case where two emitter follower circuits 54 and 56 are connected in series as a level conversion circuit. FIG. 2B shows a case where two source follower circuits 58 and 60 are connected in series as a level conversion circuit.

As described above, by connecting the level conversion circuit to the output side, the signal level attenuated by the inductor portion of the LC element 100 or the like is amplified, and predetermined level conversion or level correction can be easily performed. it can.

The point that these level conversion circuits can be integrally formed on the same substrate as the LC element 100 and the like is the same as in the case of the buffer described above.

FIG. 27 shows the LC element 1 of each of the above-mentioned embodiments.
It is a figure which shows an example of a structure at the time of adding an input protection circuit to 00 etc. LC element 1 of each embodiment having a MOS structure
00 and the like are applied to the first electrode 10 and the p-Si substrate 3 when a high voltage generated by static electricity is applied to the first electrode 10.
The insulating layer 28 interposed between the insulating layer 28 and 0 is destroyed. Therefore, a protection circuit is required to prevent the insulating layer 28 from being damaged by this static electricity.

The protection circuit shown in the same figure is composed of a plurality of diodes and resistors, and when a high voltage is applied to the electrode 10, a current is bypassed to the operating power supply line side or the case earth side. It is like this. In particular, the circuit of FIG. 9A has an electrostatic withstand voltage of several hundreds of volts, and the circuit of FIG. 9B has an electrostatic withstand voltage of 1000 to 2000V, and the protection circuit to be used can be appropriately selected according to the environment of use.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention.

For example, in each of the embodiments described above, the inversion region 22 is formed only when the predetermined positive voltage (bias voltage) is applied to the first electrode 10.
Carriers (n-type impurities or p-type impurities) may be preliminarily injected into the position of the inversion region 22 shown in FIG. Accordingly, the inversion region 22 disappears when a predetermined positive voltage is applied to the first electrode 10, or the voltage level with respect to the first electrode 10 where the inversion region 22 occurs or disappears can be changed.

In each of the above embodiments, p-
While the second electrode 26 was formed in direct contact with the surface of the Si substrate 30 and the first electrode 10 was formed with the insulating layer 28 interposed, the first and second electrodes 1 and 2 were formed.
Both 0 and 26 may be formed on the surface of the insulating layer 28.

Further, the LC element 100 and the like of the respective embodiments in which the first and second electrodes 10 and 26 are arranged on substantially the same plane,
Although the first and second electrodes 10, 26, etc. are formed on the substrate made of a single layer in the p region, the adjacent electrodes 10 are formed by forming a substantially spiral inversion layer along these electrodes. , 26 may be reliably isolated.

FIG. 28 shows the first and second electrodes 10, 2
6 is a diagram showing a cross-sectional structure in the case where a spirally-shaped inversion layer 66 is formed substantially along 6, and corresponds to FIG. 2 described above. That is, the inversion layer 66 composed of a spiral p region corresponding to the first and second electrodes 10 and 26 is formed on a part of the substrate 64 composed of the n − region. When the difference between the voltage applied to the first electrode 10 and the voltage applied to the second electrode 26 is large, as shown in FIG. When the depletion layer is formed in the outer peripheral portion and the difference is small, the inversion region 22 is not formed as shown in FIG. Therefore,
It is the same as the LC element of each of the above-described embodiments that the capacitance of the capacitor formed in a distributed constant can be switched depending on the presence or absence of the inversion region 22.

Further, as shown in a part of FIG. 9A, regarding the first and second electrodes 10 and 26 having different numbers of turns, a pnp structure is formed inside the substrate 64. , The first and second electrodes 1 having different numbers of turns
0 and 26 are electrically separated from each other, and a distributed constant capacitor is reliably formed between the first electrode 10 and the second electrode 26 that are closest to each other.

Further, in the LC element 100 of each embodiment in which the first and second electrodes 10 and 26 are arranged so as to face each other on both sides of the p-Si substrate 30, the substrate made of a single layer in the p region is sandwiched. The first and second electrodes 10 and 26 and the like are formed. The electrode 1 is formed by forming a spiral inversion layer between the circumferential portions of the electrodes 10 and 26.
It is also possible to ensure the isolation between the orbiting portions of 0 and 26.

FIG. 29 shows the first and second electrodes 10, 2
FIG. 8 is a diagram showing a cross-sectional structure in the case where a spiral-shaped inversion layer is formed between the circumferential portions of 6 and corresponds to FIG. 7 described above. That is, as shown in FIG.
A spiral inversion layer composed of the n region 74 is formed on a part of the substrate 30. In the LC element having such a structure, p− connected to the second electrode 26 having a different circulating portion is used.
Focusing on the Si substrates 30, the n regions 74 are formed between them, so that the Si substrates 30 have a pnp structure and are electrically separated from each other, so that isolation can be surely performed.

In addition, p-Si which is actually in a wafer state
When manufacturing the LC element 100 or the like of each embodiment using the substrate 30, the thickness of the p-Si substrate 30 is taken into consideration in consideration that the specific resistance of the p-Si substrate 30 is higher than that of a general metal. Needs to be thinner than the state of the wafer. In addition, considering that an n-type wafer is generally more easily available,
The structure shown in 0 may be used.

That is, as shown in FIG.
Spiral etching is performed on one surface of the Si substrate 76, and the first or second electrode 10, 26 is formed on the etched portion. Further, as shown in FIG. 3B, the first and second electrodes 1 are formed on a part of the n-Si substrate 76.
The p + region 78 is formed so as to extend substantially along each of 0 and 26, and then the back surface side of the n-Si substrate 76 corresponding to the second electrode 26 is etched, and finally the first and second regions are formed. Electrodes 10 and 26 are formed.

Further, in each of the above-mentioned embodiments, the first and second electrodes 10, which have a substantially circular spiral shape,
However, if it has a spiral shape as a whole, it may have a square shape or another spiral shape.

In each of the above embodiments, LC
Although the advantage that the element 100 or the like can be formed as a part of the LSI or the like has been described, it is not always necessary to form it as a part of the LSI or the like, and the input / output electrode 18, after the LC element 100 or the like is formed on the semiconductor substrate, Terminals may be attached to each of the 20 and the ground electrode 16, or may be attached using the chemical liquid phase method as shown in FIG. 23 to form a single element. In this case, if a plurality of LC elements 100 and the like are simultaneously formed on the same semiconductor substrate and then the semiconductor substrate is separated and terminals are attached to each LC element and the like, mass production can be easily performed. Become.

In each of the above embodiments, the second
Although the ground electrode 16 is connected to one end on the outer peripheral side of the electrode 26, the ground electrode 16 may be provided on one end on the inner peripheral side. Further, the input / output electrodes 18 and 20 and the ground electrode 16 do not necessarily have to be provided at the outermost end, and the mounting positions thereof may be shifted as necessary after examining the frequency characteristics.

Further, the LC device 100 of each of the above-mentioned embodiments.
In the above description, the case of using the p-Si substrate 30 is described as an example, but other types of semiconductors such as germanium may be used, or an amorphous material such as amorphous silicon may be used.

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[Brief description of drawings]

FIG. 1 is a plan view of an LC device according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged sectional view taken along line BB of FIG.

4 is an enlarged cross-sectional view taken along line CC of FIG.

5 is an enlarged sectional view taken along line DD of FIG.

FIG. 6 is a diagram showing an equivalent circuit of the LC element of the first embodiment.

FIG. 7 is a diagram showing a modification of the LC element of the first embodiment.

FIG. 8 is a diagram showing a modification of the LC element of the first embodiment.

9 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 10 is a diagram showing a modification of the LC element of the first embodiment.

FIG. 11 is a plan view of an LC device according to a second embodiment.

FIG. 12 is a diagram showing an equivalent circuit of the LC element of the second embodiment.

FIG. 13 is a diagram showing a modification of the LC element of the second embodiment.

FIG. 14 is a diagram showing a modification of the LC element of the second embodiment.

FIG. 15 is a diagram showing a modification of the LC element of the second embodiment.

FIG. 16 is a plan view of an LC device according to a third embodiment.

FIG. 17 is a diagram showing an equivalent circuit of the LC device of the third embodiment.

FIG. 18 is a diagram showing a modification of the LC element of the third embodiment.

FIG. 19 is a plan view of an LC device according to a fourth embodiment.

FIG. 20 is a diagram showing an equivalent circuit of the LC device of the fourth embodiment.

FIG. 21 is a diagram showing a modification of the LC element of the fourth embodiment.

FIG. 22 is a diagram schematically showing a case where terminals are attached using a chemical liquid method.

FIG. 23 is a diagram schematically showing a case where terminals are attached using a chemical liquid method.

FIG. 24 is an explanatory diagram of a case where the LC element of each example is formed as a part of an LSI or the like.

FIG. 25 is a diagram showing an example in which a buffer is connected to the output side of the LC element of each example.

FIG. 26 is a diagram showing an example in which a level conversion circuit is connected to the output side of the LC element of each example.

FIG. 27 is a diagram showing an example in which a protection circuit is connected to the input side of the LC element of each example.

FIG. 28 is a diagram showing a cross-sectional structure when a spiral inversion layer is formed on the surface of a semiconductor substrate.

FIG. 29 is a view showing a cross-sectional structure when a spiral inversion layer is formed between electrodes inside a semiconductor substrate.

FIG. 30 is a diagram showing a partial cross section when a part of a substrate is etched.

[Explanation of symbols]

10 First electrode 12 Variable bias circuit 16 Earth electrode 18, 20 Input / output electrodes 22 Inversion area 26 Second electrode 28 Insulation layer 30 p-Si substrate 32 depletion

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Claims (10)

(57) [Claims] 1. A semiconductor substrate on which a single layer of either an n region or a p region is formed on a front surface side, a spiral-shaped first electrode formed on the semiconductor substrate, and the first electrode. A second spiral-shaped electrode formed on the semiconductor substrate so as to be adjacent to the first substrate; an insulating layer formed between the first electrode and the semiconductor substrate; The inductor formed by the electrodes and the capacitor formed between the first electrode and the second electrode exist in a distributed constant manner, and the inductor of the spiral shape is formed between the first electrode and the second electrode. by setting using at least one as a signal input and output paths, the voltage applied to each of the first electrode and the second electrode variably, the semiconductor substrate surface corresponding to the first electrode of the spiral Swirl in position To generate Jo inversion region, or generated LC elements, characterized in that extinguish the inversion region. 2. A spiral-shaped first electrode formed on one surface side of a semiconductor substrate, and a position formed on the other surface side of the semiconductor substrate and substantially facing the spiral-shaped first electrode. An inductor formed by the first electrode, comprising: a spiral second electrode formed on the first electrode; and an insulating layer formed between the first electrode and the semiconductor substrate. A capacitor formed between the first electrode and the second electrode exists in a distributed constant, and at least one of the spiral-shaped first electrode and the second electrode is used as a signal input / output path, by setting the voltage applied to each of the first electrode and the second electrode variably generating the inversion region of the spiral at the position of the semiconductor substrate surface corresponding to the first electrode of the spiral Or let LC elements, characterized in that extinguishing the the inversion region. 3. The LC element according to claim 1, wherein carriers are preliminarily injected at a position on the surface of the semiconductor substrate corresponding to the spirally shaped first electrode. 4. The first and second electrodes according to claim 1, wherein the length of the second electrode is set longer or shorter than the length of the first electrode having a spiral shape. An LC device characterized in that the electrodes of the above are partially corresponded. 5. The spiral-shaped n according to claim 1, wherein the semiconductor substrate is replaced with a spiral-shaped n along the first and second electrodes. An LC element using a semiconductor substrate on which an inversion layer composed of a region or a p region is formed. 6. The method according to any one of claims 3 and 4, which depends on claim 2 and claim 2, in place of the semiconductor substrate, between each spiraling portion of the spirally shaped first and second electrodes. An LC device comprising a semiconductor substrate on which an inversion layer composed of a spiral n region or p region is formed. 7. The first and second input / output electrodes according to claim 1, wherein the first and second input / output electrodes are electrically connected to both ends of one of the first and second spiral electrodes, respectively. A ground electrode electrically connected to the other end of the spiral-shaped first and second electrodes in the vicinity of the other end thereof, and a signal is output from one of the first and second input / output electrodes. An LC element, characterized in that it inputs and outputs a signal from the other, and the ground electrode is connected to a power source of a fixed potential or grounded. 8. The first and second input / output electrodes according to claim 1, wherein the first and second input / output electrodes are electrically connected to both ends of one of the first and second spiral electrodes, respectively. A third and a fourth input / output electrode electrically connected near the other ends of the other of the spiral-shaped first and second electrodes, respectively, and the spiral-shaped first electrode An LC element used as a common mode type element having both of the second electrodes as signal input / output paths. 9. The LC element according to claim 1 is formed as a part of a substrate, and at least one of the spirally-shaped first electrode and the second electrode is inserted into a signal line or a power supply line. The semiconductor device is characterized by being integrally molded. 10. The protection circuit according to claim 1, wherein at least one of the spirally shaped first and second electrodes is provided with a protection circuit for bypassing an overvoltage to an operating power supply line side or an earth side. LC element.