JPH07142258A - Inductance-variable element - Google Patents

Abstract

PURPOSE:To provide an inductance-variable element which can change inductance under control from the outside, has a simple constitution and can be formed integrally with a semiconductor component such as an integrated circuit or the like. CONSTITUTION:An inductance-variable element 100 is constituted in such a way that a spiral electrode 10, in about 2.5 turns, which is formed on the surface of an n-Si substrate 32 via an insulating layer 30 and switches 16, 24 which are used to short-circuit individual circumferential parts of the spiral electrode 10 are included. Both ends of the spiral electrode 10 are used as input/output electrodes 12, 14 which have a wide-width shape. When only either the switch 16 or the switch 24 is set to an ON state, the element becomes a coil, in about 1.5 turns, in which the outermost circumferential part or the inner circumferential part of the spiral electrode 10 becomes invalid. When both switches 16, 24 are set to an ON state, the element becomes a coil in about 0.5 turn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductance variable element having a predetermined inductance which is incorporated in a semiconductor device or the like or used alone.

[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, and in particular, the LS has been greatly improved in the degree of integration with the progress of semiconductor manufacturing technology.
I and the like are becoming more common.

In such an integrated circuit including an LSI, a large number of semiconductor parts such as MOS • FET, bipolar transistor or diode are formed.
In addition, a capacitor using a pn junction and a resistor whose characteristics are determined by the density of minority carriers in the semiconductor are incorporated. Therefore, in such an integrated circuit, a large-scale circuit including only individual internal elements is configured with almost no external components.

[0004]

In the conventional integrated circuit described above, most of the elements can be included in the internal circuit, but only the coil is externally attached. Moreover, since the inductance of this coil is determined by the shape of the coil, it is impossible to change it as needed.
For example, one that has a magnetic core that moves in and out of a coil is known as a device that sets the inductance variably, but when changing the inductance, it is necessary to shift the position of this magnetic core. Is not suitable for use as part of an electronic circuit because it becomes complicated.

Therefore, the present invention was created in view of the above point, and an object thereof is to provide an inductance variable element having a simple structure, which can change the inductance by external control. It is in.

Another object of the present invention is to provide an inductance variable element which can be integrally formed with a semiconductor component such as an integrated circuit.

[0007]

In order to solve the above-mentioned problems, the invention of claim 1 separates the plurality of inductor conductors, which have a spiral shape as a whole or individually, from the plurality of inductor conductors. One or a plurality of switches to be connected, and any one of the plurality of inductor conductors is used alone or in combination.

A second aspect of the invention is the invention of the first aspect, further comprising two input / output terminals provided near both ends of the plurality of inductor conductors each having a spiral shape, and switching the switch. By the above 2
It is characterized in that the inductance between the two input / output terminals is changed by switching the number of the plurality of inductor conductors existing between one input / output terminal.

According to a third aspect of the present invention, in the first aspect of the invention, the plurality of inductor conductors are formed on a semiconductor substrate with an insulating layer interposed therebetween, and the switch is formed on a part of the semiconductor substrate. Is a field effect transistor in which two diffusion regions are respectively connected to a part of the plurality of inductor conductors different from each other, and the plurality of inductor conductors and the switch are integrally formed on the semiconductor substrate. It is characterized by being formed.

According to a fourth aspect of the present invention, in the third aspect of the invention, the field effect transistor forming the switch is
It is a transmission gate in which an n-channel transistor and a p-channel transistor are connected in parallel.

According to a fifth aspect of the present invention, in any one of the third or fourth aspect of the invention, after the switch and the inductor conductor are formed on the semiconductor substrate, a chemical liquid phase is formed on the entire surface of the semiconductor substrate. Characterized in that an insulating film is formed by a method, a part of the insulating film is removed by etching or laser light irradiation to form a hole, and the hole is sealed to the extent that it rises on the surface for terminal attachment. .

[0012]

The variable inductance device according to the first aspect has a plurality of inductor conductors, and these conductors are used by being connected or separated by a switch. In addition, each of these inductor conductors has a circular shape as a whole or individually, and by changing the connection state of each of these inductor conductors by switching a switch, the overall inductance can be adjusted according to this connection state. Will be switched.

According to the first aspect of the invention, the connection state of the plurality of inductor conductors is switched by operating the switch, whereby the inductance can be changed.

Further, the variable inductance element according to claim 2 has two input / output terminals near both ends of the plurality of inductor conductors described above, and is connected between these two input / output terminals by switching a switch. The number of inductor conductors is switched. Therefore, it is possible to change only the inductance of the element while fixing the input / output terminal used.

According to a third aspect of the variable inductance element, the inductor conductor is formed on a semiconductor substrate via an insulating layer, and the switch is provided with a diffusion region in a part of the semiconductor substrate. It is formed by a field effect transistor. Therefore, by changing the voltage applied to the gate of this field effect transistor, connection and separation between the inductor conductors are performed.

According to the invention of claim 3, since the inductor conductor and the switch are formed on the semiconductor substrate, the structure is simple, and the inductance variable element is integrated with a semiconductor component such as an integrated circuit or a transistor. Can be formed.

According to a fourth aspect of the variable inductance element, the field effect transistor is a transmission gate in which an n-channel transistor and a p-channel transistor are connected in parallel, whereby a diffusion region and a gate functioning as a source or a drain are provided. It is possible to always perform stable and low-resistance switching operation without depending on the potential difference.

In the variable inductance element according to a fifth aspect of the invention, the insulating variable film is formed on the entire surface by the chemical liquid phase method after the variable inductance element is formed on the semiconductor substrate. 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, it is possible to easily manufacture the surface-mounting type element, and by using the surface-mounting type element, the assembling work of this element becomes easy.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An inductance variable element 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 inductance variable element of a first embodiment to which the present invention is applied. 2 is a partially enlarged view of the vicinity of the switch in the variable inductance element shown in FIG.

As shown in these figures, the variable inductance element 100 of the present embodiment has a spiral electrode formed on the surface of an n-type silicon substrate (n-Si substrate) 32, which is a semiconductor substrate, with an insulating layer 30 interposed therebetween. 10 and a switch 1 for short-circuiting each spiraling part of the spiral electrode 10.
6 and 24 are included.

The spiral electrode 10 has a spiral shape of about 2.5 turns, and its both end portions have a wider shape than other winding portions. One of the wide portions (outer peripheral side) of the both ends serves as the input / output electrode 12, and the other (inner peripheral side) serves as the input / output electrode 14.

The spiral electrode 10 is made of, for example, a metal material such as aluminum or copper, but it may be made of a semiconductor material such as polysilicon.

The switch 16 is for partially short-circuiting the outermost peripheral portion of the spiral electrode 10 and the second peripheral portion from the outer peripheral side, and has a stepped rectangular shape formed on the surface of the insulating layer 30. A gate electrode 18 having
Two diffusion regions 20, 2 formed in the vicinity of the surface of the Si substrate 32 so as to partially overlap the gate electrode 18.
2 and.

The gate electrode 18 is formed using a metal material such as aluminum or copper or a semiconductor material such as polysilicon, like the spiral electrode 10 described above.
Further, each of the diffusion regions 20 and 22 is formed by thermal diffusion or ion implantation of p-type impurities into the n-Si substrate 2.
It is formed by injecting into a part of 0, and one corresponds to the source of the field effect transistor and the other corresponds to the drain.

These two diffusion regions 20 and 22 are arranged adjacent to each other with a portion corresponding to the gate electrode 18 interposed therebetween, and by applying a predetermined negative voltage to the gate electrode 18, a p-type channel is formed. Are formed, they become mutually conductive by this channel. Moreover, since one diffusion region 20 is connected to a part of the outermost peripheral part of the spiral electrode 10 and the other diffusion region 22 is connected to a part of the second peripheral part from the outside, two diffusion regions are formed. Area 2
When 0 and 22 are electrically connected, the outermost peripheral portion and the second peripheral portion of the spiral electrode 10 are partially short-circuited.

Similarly, the switch 24 is for partially short-circuiting the second circumferential portion of the spiral electrode 10 from the outer circumferential side and the innermost circumferential portion, and is formed on the surface of the insulating layer 30. The gate electrode 26 having a stepped rectangular shape is formed in the vicinity of the surface of the n-Si substrate 32 so as to partially overlap the gate electrode 26.
It is composed of two diffusion regions 22 and 28.

The diffusion region 28 is used for the other diffusion regions 20, 22.
Similarly, the p-type impurities are formed by thermal diffusion or ion implantation into a part of the n-Si substrate 32, and one of the diffusion regions 22 and 28 is a source of the field effect transistor and the other is a drain. Is equivalent to.

These two diffusion regions 22 and 28 are arranged adjacent to each other with a portion corresponding to the gate electrode 26 sandwiched therebetween. By applying a predetermined negative voltage to the gate electrode 26, a p-type channel is formed. Are formed, they become mutually conductive by this channel. In addition, one diffusion region 22 is connected to a part of the second circular portion from the outer side, and the other diffusion region 28 is connected to a part of the innermost circular portion. Area 22, 28
When the gaps are electrically connected, the innermost peripheral portion and the second peripheral portion of the spiral electrode 10 are partially short-circuited.

FIG. 3 is a view showing a cross section taken along the line BB of FIG. As shown in the figure, p-type diffusion regions 20, 22, and 28 are formed in the vicinity of the surface of the n-Si substrate 32 and at positions corresponding to a part of each lap portion of the spiral electrode 10. Further, the gate electrodes 18 and 26 are formed with the insulating layer 30 sandwiched therebetween so as to fill the spaces between the diffusion regions 20, 22, and 28, respectively.
8, 26, the insulating layer 30, and the n-Si substrate 32
An IS (metal-insulator-semiconductor) structure or a MOS (metal-oxide-semiconductor) structure is formed.

Therefore, paying attention to the structure in the vicinity of one of the gate electrodes 18, a field effect transistor in which each of the two diffusion regions 20 and 22 functions as a source or a drain is formed, and this field effect transistor functions as the switch 16. Will be done. That is, when a predetermined negative voltage is applied to the gate electrode 18, p is generated near the surface of the n-Si substrate 32 facing the gate electrode 18.
A channel 34 of the mold is formed, and by this channel 34, conduction is established between the two diffusion regions 20 and 22,
A predetermined switching operation is performed.

Similarly, paying attention to the structure near the other gate electrode 26, a field effect transistor in which each of the two diffusion regions 22 and 28 functions as a source or a drain is formed, and this field effect transistor serves as the switch 24. As a result, the predetermined switching operation is performed.

As described above, in the variable inductance element 100 of this embodiment, a predetermined negative voltage is applied to the gate electrode 18 to turn on the switch 16 so that the switch shown in FIG.
2 from the outermost portion of the spiral electrode 10 shown in FIG.
It is possible to partially short-circuit the second circulation part. Therefore, when a predetermined negative voltage is applied to only one of the gate electrodes 18, the one-turn portion located at the outermost periphery of the spiral electrode 10 can be invalidated, and the device has about 1.5 turns as a whole. Can be used as

Similarly, by applying a predetermined voltage to the gate electrode 26 and turning on the switch 24, the second winding portion and the innermost winding portion can be partially short-circuited. it can. Therefore, when a predetermined negative voltage is applied only to the other gate electrode 26, one turn portion located substantially on the inner peripheral side of the spiral electrode 10 can be invalidated, and about 1.5 turns as a whole. Can be used as a coil. In addition, switch 1
When only one of 6 and 24 is turned on, there is no change in that it becomes a coil of about 1.5 turns, but since the invalid part is different, the inductance as a whole is not the same, It can be used properly according to the purpose of use.

Further, by applying a predetermined negative voltage to both of the two gate electrodes 16 and 18, the switches 16 and 24 are
If both are turned on, the spiral electrode 1
Since all three winding portions of 0 are short-circuited to each other, the coil is about 0.5 turns including the outer portion of the switch 16 and the inner portion of the switch 24, and the inductance component can be almost removed.

Therefore, if necessary, the gate electrode 1
By applying a predetermined voltage to 8 and 26 to turn on the switches 16 and 24, 2.5 turns as a whole,
A coil with 1.5 turns or 0.5 turns can be used properly, and the inductance can be variably controlled by changing the number of turns.

Particularly, when viewed from the outside, the two input / output electrodes 1
Since the inductance between 2 and 14 becomes a variable controllable element, by connecting the variable inductance element 100 to a part of the circuit and then applying a predetermined voltage to the gate electrodes 18 and 26 from the outside. Since the inductance can be arbitrarily changed, it is possible to use the coil differently from the conventional coil whose characteristic value is fixed. For example, when making a tuning circuit having a plurality of transmission / reception frequencies determined in advance, the short-circuit position of the spiral electrode 10 is determined so as to have an inductance corresponding to the plurality of transmission / reception frequencies, and the gate electrode 18 and the like and diffusion are provided at this position. Area 2
It is sufficient to form 0 or the like.

Further, since the variable inductance element 100 of this embodiment can be manufactured on the n-Si substrate 32 by using a general semiconductor manufacturing technique (particularly, MOS technique), it can be easily downsized and mass-produced. Becomes It is also possible to form another semiconductor component such as another FET or bipolar transistor in the same substrate. In such a case, the semiconductor component such as an integrated circuit and the inductance variable element 100 of this embodiment are formed on the same substrate. It can be integrally molded on top. As a result, it is possible to manufacture a switching regulator or the like, which has conventionally been provided with an external coil, with the internal coil.

Further, since the variable inductance element 100 of this embodiment does not have a movable part such as a magnetic core, it has a simple structure and is suitable for being incorporated in a part of a circuit.

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

The variable inductance element 100 of the first embodiment described above is a spiral electrode 10 having a spiral shape.
The inductance between the two input / output electrodes 12 and 14 is variably controlled by short-circuiting a part of each of them by switches 16 and 24 formed by field effect transistors, and the short circuit causes a single or double closed loop. Is formed. On the other hand, the variable inductance element 200 of the present embodiment is characterized in that the formation of a closed loop at the time of short circuit is prevented.

FIG. 4 is a plan view of an inductance variable element according to the second embodiment of the present invention. FIG. 5 is a partially enlarged view of the vicinity of the switch of the variable inductance element shown in FIG.

As shown in these figures, in the variable inductance element 200 of this embodiment, the spiral electrode 10 having a spiral shape of about 2.5 turns is formed on the surface of the n-Si substrate 32 via the insulating layer 30. Has been done. Further, the spiral electrode 10 includes three split spiral electrodes 10-1, 10-2, 10- having a spiral shape as a whole.
The third embodiment is different from the first embodiment in this respect.

Further, the split spiral electrodes 10-1 and 10
-2, these two split spiral electrodes 10-
A switch 40 for connecting or disconnecting 1 and 10-2 in series is arranged. Similarly, a switch 46 for connecting or disconnecting these two divided spiral electrodes 10-2 and 10-3 in series is arranged between the divided spiral electrodes 10-2 and 10-3. Therefore, only when the switches 40 and 46 are both turned on, the three divided spiral electrodes 10-
1 to 10-3 function as one inductor conductor,
The coil becomes about 2.5 turns as a whole.

The switch 40 described above includes a gate electrode 42 having a stepped rectangular shape formed between the split spiral electrodes 10-1 and 10-2, and an n-Si substrate 32.
Is formed on a part of the surface of each of the divided spiral electrodes 10-1 and 10-2, and each of the divided diffusion electrodes 20 and 44 is connected to a part of the divided spiral electrodes 10-1 and 10-2.
The switch 40 is a field-effect transistor in which each of the diffusion regions 20 and 44 functions as a source or a drain. By applying a predetermined negative voltage to the gate electrode 42, the switch 40 is provided between the two diffusion regions 20 and 44. A channel is formed and this switch 40 is turned on.

Similarly, the switch 46 includes a gate electrode 48 having a stepped rectangular shape formed between the divided spiral electrodes 10-2 and 10-3, and an n-Si substrate 32.
Is formed on a part of the surface of each of the divided spiral electrodes 10-2 and 10-3, and each of the divided spiral electrodes 10-2 and 10-3 is formed of two diffusion regions 22 and 50.
The switch 46 is a field effect transistor in which each of the diffusion regions 22 and 50 functions as a source or a drain. By applying a predetermined negative voltage to the gate electrode 48, the switch 46 is provided between the diffusion regions 22 and 50. A channel is formed and the switch 46 is turned on.

FIG. 6 shows an inductor variable element 2 of this embodiment.
00 is a partial cross-sectional view of FIG. The same figure (A) is A- of FIG.
FIG. 4 is a sectional view taken along line A, which is basically the same as the sectional structure shown in FIG. 3 in the first embodiment. 6B is a cross-sectional view taken along the line BB of FIG. 5, in which two diffusion regions 20 and 4 are formed by applying a predetermined negative voltage to the gate electrode 42.
A channel 52 is formed between the four.

As described above, in the variable inductance element 200 of this embodiment, in addition to the two switches 16 and 24 for short-circuiting a part of the spiral electrode 10, the divided spiral electrodes 10- forming the spiral electrode 10- 1-1
It has switches 40 and 46 for connecting or disconnecting each of 0-3 in series.

Then, only the switch 16 is turned on to short-circuit the outermost peripheral portion of the spiral electrode 10 and the second peripheral portion from the outside, and a coil of about 1.5 turns is provided between the input / output electrodes 12 and 14. When forming, switch 40
Is turned off to disconnect one end of the split spiral electrode 10-2 to prevent the split spiral electrode 10-2 from forming a closed loop.

Similarly, only the switch 24 is turned on to short-circuit the second circumference portion and the innermost circumference portion of the spiral electrode 10 from the outer side, and about 1.5 turns are made between the input / output electrodes 12 and 14. When forming the coil, the switch 46
Is turned off to disconnect one end of the split spiral electrode 10-3 to prevent the split spiral electrode 10-3 from forming a closed loop.

In the above two cases, both are about 1.
Although the coil has 5 turns, a slight difference occurs in the magnetic flux density generated depending on which split spiral electrode is used, and therefore the inductance between the two input / output terminals 12 and 14 also slightly differs.

When both the switches 16 and 24 are turned on to short-circuit each spiraling portion of the spiral electrode 10 to form a coil of about 0.5 turns between the input / output electrodes 12 and 14. Turns off both the switches 40 and 46 to prevent the formation of a closed loop by the split spiral electrodes 10-2 and 10-3.

Further, both of the switches 16 and 24 are turned off, and the respective divided spiral electrodes 10-1 to 10-3 are connected in series, and about 2.5 turns between the input / output electrodes 12 and 14 are achieved. When forming the coil, switch 4
Both 0 and 46 may be turned on.

As described above, the variable inductance element 200 of this embodiment has the spiral electrode 10 having a spiral shape.
By partially shorting part of the switch 16 and 24, the total number of turns is 2.5 to 0.5.
It can change between turns. This allows the inductance between the two input / output electrodes 12 and 14 to be variably set.

Also, in the variable inductance element 200 of this embodiment, when the spiral electrode 10 is partially short-circuited, one end of the split spiral electrode not used as a coil can be separated by the switches 40 and 46. As a result, it is possible to prevent formation of an unnecessary closed loop, and it is possible to prevent generation of an unnecessary closed loop current due to the generation of magnetic flux.

The variable inductance element 200
It is the same as the first embodiment described above in that it can be manufactured by using a general semiconductor manufacturing technique, and accordingly, it can be downsized and mass-produced.

Third Embodiment Next, an inductance variable element according to a third embodiment of the present invention will be specifically described with reference to the drawings.

In the variable inductance elements 100 and 200 of the first and second embodiments described above, the number of turns is changed by partially short-circuiting each spiraling portion of the spiral electrode 10 having a spiral shape. On the other hand, the variable inductance element 300 of the present embodiment is characterized in that the number of turns is changed without short-circuiting the winding portion.

FIG. 7 is a plan view of an inductance variable element according to a third embodiment of the present invention. 8 is a partially enlarged view of the vicinity of the switch of the variable inductance element shown in FIG.

As shown in these figures, the variable inductance element 300 of the present embodiment has a spiral electrode 10 and a line electrode 60 formed on the surface of an n-Si substrate 32 via an insulating layer 30, and these two electrodes. Four switches 62, 68, 74, 80 for connecting the electrodes 10, 60
It is configured to include and.

The spiral electrode 10 has a spiral shape of about 3 turns, and one end of the outer peripheral side thereof is an input / output electrode 12 having a wide shape. Line electrode 60
Has a plurality of linear portions each having a convex shape, and the linear portions are arranged so as to be orthogonal to the respective spiraling portions of the spiral electrode 10 with an insulating layer interposed therebetween. Also,
One end of the line electrode 60 (outer peripheral side of the spiral electrode 10) is the input / output electrode 14 having a wide shape.

The switch 62 is for electrically connecting the outermost peripheral portion of the spiral electrode 10 and a part of the line electrode 60, and has a stepped rectangular shape formed on the surface of the insulating layer 30. The gate electrode 63 and two diffusion regions 64 and 66 that are formed in the vicinity of the surface of the n-Si substrate 32 so as to partially overlap the gate electrode 63. By applying a predetermined negative voltage to the gate electrode 63, the two diffusion regions 64,
A p-type channel is formed between 66, the switch 62 is turned on, and the outermost peripheral portion of the spiral electrode 10 and the line electrode 60 are connected to each other.

Similarly, the switch 68 is for electrically connecting the second circumferential portion of the spiral electrode 10 from the outside and a part of the line electrode 60, and the insulating layer 30.
Gate electrode 69 having a stepped rectangular shape formed on the surface of the n-Si substrate 32 and two diffusion regions 70, 72 formed near the surface of the n-Si substrate 32 so as to partially overlap the gate electrode 69. It consists of and. By applying a predetermined negative voltage to the gate electrode 69, the switch 68 is turned on, and the second circumferential portion of the spiral electrode 10 from the outside and the line electrode 60 are connected to each other.

The switch 74 is for electrically connecting the third circumferential portion of the spiral electrode 10 from the outside and a part of the line electrode 60, and has a step formed on the surface of the insulating layer 30. Gate electrode 75 having a rectangular shape
And the gate electrode 7 near the surface of the n-Si substrate 32.
5 and two diffusion regions 76 and 78 formed so as to partially overlap each other. This gate electrode 75
By applying a predetermined negative voltage to the switch 74, the switch 74 is turned on, and the third circumferential portion of the spiral electrode 10 from the outside and the line electrode 60 are connected to each other.

The switch 80 is for electrically connecting the inner end of the spiral electrode 10 and a part of the line electrode 60, and has a stepped rectangular shape formed on the surface of the insulating layer 30. The gate electrode 81 is included, and two diffusion regions 82 and 84 are formed in the vicinity of the surface of the n-Si substrate 32 so as to partially overlap the gate electrode 81. By applying a predetermined negative voltage to the gate electrode 81, the switch 80 is turned on, and the inner end of the spiral electrode 10 and the line electrode 60 are connected to each other.

FIG. 9 is a view showing a cross section taken along the line AA of FIG. In the figure, focusing on the switch 62, the n-Si substrate 32 is sandwiched so as to sandwich the gate electrode 63 on the insulating layer 30.
Two diffusion regions 64 and 66 are formed near the surface of the gate electrode 63, and a channel 86 is formed between the two diffusion regions 64 and 66 by applying a predetermined negative voltage to the gate electrode 63. , A predetermined switching operation is performed.

Similarly, focusing on the switch 68, the n-Si substrate 3 is sandwiched so as to sandwich the gate electrode 69 on the insulating layer 30.
Two diffusion regions 70 and 72 are formed near the surface of No. 2, and a channel 88 is formed between the two diffusion regions 70 and 72 by applying a predetermined negative voltage to the gate electrode 69. Then, a predetermined switching operation is performed.

Focusing on the switch 74, two diffusion regions 76 and 78 are formed in the vicinity of the surface of the n-Si substrate 32 so as to sandwich the gate electrode 75 on the insulating layer 30. A negative voltage is applied to form a channel 90 between these two diffusion regions 76 and 78, and a predetermined switching operation is performed.

Focusing on the switch 80, two diffusion regions 82 and 84 are formed in the vicinity of the surface of the n-Si substrate 32 so as to sandwich the gate electrode 81 on the insulating layer 30. A negative voltage is applied to form a channel 92 between these two diffusion regions 82 and 84, and a predetermined switching operation is performed.

As described above, in the variable inductance element 300 of the present embodiment, when only the switch 80 is turned on, the coil of about 3 turns between the two input / output electrodes 12 and 14 effectively functions. Further, when only the switch 74 is turned on, the coil of about 2 turns effectively works, and when only the switch 68 is turned on, the coil of about 1 turn works effectively. Furthermore, when only the switch 62 is turned on, a coil having a spiral shape is not formed, and the element has a very small inductance. Therefore, the number of turns of the coils connected to the two input / output electrodes 12 and 14 can be changed by changing the gate electrode to which a predetermined voltage is applied, and thus the inductance can be variably set.

Incidentally, this variable inductance element 300
It is the same as the first and second embodiments described above in that it can be manufactured by using a general semiconductor manufacturing technology, and accordingly, it can be downsized and mass-produced.

Other Embodiments Next, variable inductance elements according to other embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 10 is a plan view of an inductance variable element according to the fourth embodiment of the present invention. In addition, FIG.
FIG. 11 is a partially enlarged view of the vicinity of the switch of the variable inductance element shown in FIG. 10.

As shown in these figures, the variable inductance element 400 of the present embodiment has two spiral electrodes 110 and 112 having a spiral shape of approximately one turn, and two switches for connecting or disconnecting them. 122,1
30 and 30 are included.

One end of the spiral electrode 110 is an input / output electrode 114 having a wide shape, and the other end is connected to the spiral electrode 112 via a switch 122.
A part of it has a branched shape toward the input / output electrode 118. Further, one end of the spiral electrode 112 is the input / output electrode 120 having a wide shape, and the other end is connected to the spiral electrode 110 via the switch 122 as described above and is also input via the switch 130. Output electrode 1
It is connected to 16.

The switch 122 has two rotating electrodes 110.
And 112 for connecting the gate electrode 124 having a stepped rectangular shape formed on the surface of the insulating layer 30 and the insulating layer 30 in the vicinity of the surface of the n-Si substrate 32. It is composed of two diffusion regions 126 and 128 formed so as to partially overlap the gate electrode 124, and is turned on by applying a predetermined negative voltage to the gate electrode 124.

Further, the switch 130 is for connecting the one-turn electrode 112 and the input / output electrode 116, and the gate electrode 132 having a stepped rectangular shape formed on the surface of the insulating layer 30, Two diffusion regions 13 formed in the vicinity of the surface of the n-Si substrate 32 so as to partially overlap the gate electrode 132 with the insulating layer 30 interposed therebetween.
The gate electrode 132 is turned on by applying a predetermined negative voltage to the gate electrode 132.

As described above, in the variable inductance element 400 of this embodiment, when only the switch 122 is turned on, the two winding electrodes 110 and 112 are connected,
A coil of about 2 turns is formed between the input / output electrodes 114 and 120. When the switch 130 is turned on and the switch 122 is turned off, a coil of about one turn formed by the circulating electrode 110 is formed between the input / output electrodes 114 and 120, and Circular electrode 112 between 116 and 118
A coil of about 1 turn is formed.

Therefore, by switching the on / off states of the switches 122 and 130, it is possible to divide and use the coil of about 2 turns as a whole as needed. Moreover, since the inductance between the input and output electrodes changes depending on the number of turns of the coil formed between them and which winding electrode is used, the inductance variable element can be selected by selecting the input and output terminals to be used as needed. 400 can be used as an element with multiple inductances.

The variable inductance element 4 described above is used.
In the case of 00, a coil having about 2 turns is formed as a whole, but the number of selectable inductances can be increased by increasing the number of turns and the number of switches and input / output electrodes. Further, it is not necessary to arrange a plurality of winding electrodes concentrically, and adjacent winding electrodes may be connected or separated.

FIG. 12 is a plan view of the variable inductance element according to the fifth embodiment of the present invention. In addition, FIG.
FIG. 13 is a partially enlarged view of the vicinity of the switch of the variable inductance element shown in FIG. 12.

The variable inductance element 500 of this embodiment.
Is the variable inductance element 10 shown in FIGS.
It is characterized in that the characteristics of the switch portion of 0 are improved. Generally, the on-resistance of a field effect transistor depends on the potential difference between the source and the gate, and the on-resistance between the source and drain tends to increase rapidly as the potential difference decreases. Therefore, the input / output electrodes 12 or 14
The voltage level of the signal input from the gate electrodes 18, 2
When the gate voltage applied to 6 is approached, the resistance between the two input / output electrodes 12 and 14 becomes high, causing signal attenuation. Variable inductance element 500 of the present embodiment
In order to prevent the above-mentioned rapid increase in on-resistance, the switching operation is performed using a transmission gate in which a p-channel FET and an n-channel FET are connected in parallel.

As shown in FIGS. 12 and 13, the variable inductance element 500 of this embodiment is different from the variable inductance element 100 shown in FIG.
It has a configuration in which two switches 140 and 148 made of ET are added. These two switches 140,14
8 is a p well 1 formed in a part of the n-Si substrate 32.
It is formed near the surface of 38.

The switch 140 is connected in parallel with the switch 16 to partially short-circuit the outermost peripheral portion of the spiral electrode 10 and the second peripheral portion from the outside, and the gate electrode 18 of the switch 16 is provided. , Diffusion area 20,
A gate electrode 142 and diffusion regions 144 and 146 are provided corresponding to each 22.

For the gate electrode 142 of the switch 140,
A predetermined positive voltage having a polarity different from that of the voltage applied to the gate electrode 18 of the switch 16 is applied, and at this time, an n-type channel is formed between the two diffusion regions 144 and 146 to establish a conductive state. Note that the gate electrodes 18 and 1 are actually
To apply voltages of different polarities to 42 and
The combination of the voltages applied to the Si substrate 32 and the gate electrode 18 is reversed, and the p well 138 and the gate electrode 14 are combined.
It is only necessary to apply it to

Similarly, the switch 148 is the switch 24.
2 connected from the outside of the spiral electrode 10 in parallel with
This is for partially short-circuiting the second circumference portion and the innermost circumference portion, and corresponds to the gate electrode 26 of the switch 24 and the diffusion regions 22 and 28, respectively.
8 and diffusion regions 146 and 152 are provided.

For the gate electrode 150 of the switch 148,
A predetermined positive voltage having a polarity different from that of the voltage applied to the gate electrode 26 of the switch 24 is applied, and at this time, an n-type channel is formed between the two diffusion regions 146 and 152 to be in a conductive state.

FIG. 14 is a partial sectional view of the variable inductance element 500 of this embodiment. FIG.
3 is a cross-sectional view taken along the line AA of FIG. 3, showing an n-channel FET switch 140 including a gate electrode 142 and diffusion regions 144 and 146 in a p well 138 formed in a part (near the surface) of the n-Si substrate 32. , The gate electrode 150 and the switch 148 of the n-channel FET formed of the diffusion regions 146, 152 are both formed.
14B is a cross-sectional view taken along the line BB of FIG.
The cross-sectional structure of the first embodiment is basically the same as that shown in FIG.

As described above, by using the switches 16 and 140 connected in parallel (or the switches 24 and 148 connected in parallel) as a transmission gate, a signal input to, for example, the input / output electrode 12 or 14 can be obtained. When the voltage level of the switch 16 approaches the gate voltage applied to the gate electrode 18 of the one switch 16, it moves away from the gate voltage applied to the gate electrode 142 of the other switch 140, and the switches 16 and 140
The on resistance of the entire parallel circuit composed of and becomes low. On the contrary, when the voltage level of the input signal approaches the gate voltage applied to the gate electrode 142 of the other switch 140, the voltage level goes away from the gate voltage applied to the gate electrode 18 of the one switch 16, The on-resistance of the entire parallel circuit including the switches 16 and 140 is low.

As described above, by using the transmission gate, the ON resistance is always stable and the characteristic of the variable inductance element 500 can be stabilized.

FIG. 15 is a plan view of an inductance variable element according to a sixth embodiment of the present invention.

The variable inductance element 600 of this embodiment.
Is characterized in that each of the switches 16 and 24 of the variable inductance element 100 shown in FIG. 1 is extended along the gap between the spiral electrodes 10. That is, focusing on one switch 16, each of the gate electrode 18 and the diffusion regions 20 and 22 is about ¼ of the spiral electrode 10.
It extends to the length of one turn. Similarly, focusing on the other switch 24, the gate electrode 26, the diffusion region 22,
Each of 28 is extended to the length of about 1/4 turn of the spiral electrode 10.

As described above, by setting the lengths of the switches 16 and 24 in the circulating direction to be long, it is possible to drastically reduce the on-resistance, and input / output of signals via the switches 16 and 24. The attenuation of the signal level when it is performed can be suppressed to a substantially negligible level.

FIG. 16 is a schematic view showing a case where terminals are attached using the chemical liquid phase method, and an enlarged cross section taken along the line AA of FIG. 1 is shown.

As shown in FIG. 16, after the semiconductor substrate including the variable inductance element 100 is cut off, a silicon oxide film 160 is formed as an insulating film on the entire surface of the individually cut chips (elements) by the chemical liquid phase method. To do. After that, the silicon oxide film 160 on the input / output electrodes 12 and 14 and the gate electrodes 18 and 26 is removed by etching to form a hole, and the hole is sealed with solder 162 to the extent that the solder 162 protrudes, so that the protruding solder 162 is removed. Since it can be directly contacted with the land of the printed wiring board,
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.

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

For example, in the variable inductance element of each of the above-described embodiments, one element is formed on the n-Si substrate 32, but the same or different types of the variable inductance element are formed on the same n-Si substrate. It is also possible to form a plurality of layers on 32 at the same time, separate them, and then attach terminals to the input / output electrodes and gate electrodes.

Since the variable inductance element of each of the above-described embodiments is the same as a general transistor in that it is formed on a semiconductor substrate, the variable inductance element of each of the embodiments is used as a part of a circuit such as an LSI. It may be formed as.

Further, since the variable inductance element of each of the above-mentioned embodiments uses the field effect transistor when the inductance is variably set, there is always an on resistance, and this on resistance has temperature dependency. Therefore, in order to correct the temperature dependence of the ON resistance, a positive temperature coefficient thermistor (PTC) or a negative temperature coefficient thermistor (NTC) may be connected inside or outside the variable inductance element.

Further, as the switch, an element other than the field effect transistor, for example, a bipolar transistor may be used.

In the variable inductance element 600 shown in FIG. 15, the lengths of the gate electrodes 18, 26, etc. are extended to about 1/4 turn. However, this length is about 1 turn. It may be extended to. In this case, the ON resistance of each switch 16 and 24 can be further reduced, and the closed loop that occurs when each switch 16 and 24 is turned ON can be completely eliminated.

Further, although the variable inductance element of each of the above-described embodiments has been described as an example in which it is used alone, the spiral variable electrode is arranged to face the inductance variable element of each embodiment, or substantially parallel thereto. By doing so, an IC element in which a capacitor is formed in a distributed constant manner between the spiral electrode 10 of each variable inductance element and the additional spiral electrode can be obtained.

In the variable inductance element of each of the above-described embodiments, the case where the inductance is changed by substantially controlling the number of turns of the spiral spiral electrode 10 has been described as an example. When the frequency band of the signal is limited to a high frequency, the shape of the spiral electrode may be a shape other than the spiral shape, for example, an arbitrary meandering shape such as a corrugated shape, and adjacent electrodes may be short-circuited. With respect to a high-frequency signal, even when it has such a shape, it has a predetermined inductance, and this inductance can be variably controlled.

[0105]

As described above, according to the invention of claim 1,
The switch switches the connection state of the plurality of inductor conductors, which allows the inductance to be changed.

According to the invention of claim 2, two inductors have two input / output terminals in the vicinity of both ends of the above-mentioned inductor conductor, and the switch is switched to connect between these two input / output terminals. The number of inductor conductors is switched. Therefore, it is possible to change only the inductance of the element while fixing the input / output terminal used.

According to the third aspect of the present invention, the inductor conductor described above is formed on the semiconductor substrate via the insulating layer, and the switch described above is provided with a diffusion region in a part of the semiconductor substrate. It is formed by a field effect transistor. Therefore, by changing the voltage applied to the gate of the field effect transistor, the connection and separation between the inductor conductors can be performed. In particular, since the inductor conductor and the switch are formed on the semiconductor substrate, the structure is simple and the element can be formed integrally with a semiconductor component such as an integrated circuit or a transistor.

According to a fourth aspect of the present invention, the field effect transistor is a transmission gate in which an n-channel transistor and a p-channel transistor are connected in parallel, whereby a diffusion region and a gate functioning as a source or a drain are provided. It is possible to always perform stable and low-resistance switching operation without depending on the potential difference.

Further, according to the invention of claim 5, after forming the above-described variable inductance element on the semiconductor substrate, the insulating film is formed on the entire surface by the chemical liquid phase method. afterwards,
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, it is possible to easily manufacture the surface-mounting type element, and by using the surface-mounting type element, the assembling work of this element becomes easy.

[Brief description of drawings]

FIG. 1 is a plan view of an inductance variable element according to a first embodiment of the present invention.

2 is a partially enlarged view of the variable inductance element of FIG. 1. FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a plan view of an inductance variable element according to a second embodiment of the present invention.

FIG. 5 is a partially enlarged view of the variable inductance element of FIG.

6 is a cross-sectional view taken along the line AA and the line BB in FIG.

FIG. 7 is a plan view of an inductance variable element according to a third embodiment of the present invention.

8 is a partially enlarged view of the variable inductance element shown in FIG. 7. FIG.

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

FIG. 10 is a plan view of an inductance variable element according to a fourth exemplary embodiment of the present invention.

FIG. 11 is a partially enlarged view of the variable inductance element of FIG.

FIG. 12 is a plan view of an inductance variable element according to a fifth exemplary embodiment of the present invention.

13 is a partially enlarged view of the inductance variable element of FIG.

14 is a cross-sectional view taken along the line AA and the line BB in FIG.

FIG. 15 is a plan view of an inductance variable element according to a sixth embodiment of the present invention.

FIG. 16 is an explanatory diagram of a case where terminals are attached using a chemical liquid method.

[Explanation of symbols]

 10 spiral electrode 12,14 input / output electrode 16,24 switch 18,26 gate electrode 20,22,28 diffusion region 30 insulating layer 32 n-Si substrate

Claims (5)

[Claims] 1. A plurality of inductor conductors, which have a circular shape as a whole or individually, and a plurality of inductor conductors which are separated or connected.
An inductance variable element, comprising one or a plurality of switches, and using any of the plurality of inductor conductors alone or in combination. 2. The input / output terminal according to claim 1, further comprising two input / output terminals provided near both ends of the plurality of inductor conductors having a circular shape as a whole, and the two input / output terminals are switched by switching the switch. An inductance variable element, characterized in that the inductance between the two input / output terminals is changed by switching the number of the plurality of inductor conductors existing between the terminals. 3. The inductor according to claim 1, wherein the plurality of inductor conductors are formed on a semiconductor substrate via an insulating layer, the switch is formed on a part of the semiconductor substrate, and two diffusions are provided. A field effect transistor in which each of the regions is connected to a part of the plurality of inductor conductors different from each other, wherein the plurality of inductor conductors and the switch are integrally formed on the semiconductor substrate, Variable inductance element. 4. The variable inductance element according to claim 3, wherein the field effect transistor forming the switch is a transmission gate in which an n-channel transistor and a p-channel transistor are connected in parallel. 5. The insulating film according to claim 3, wherein after forming the switch and the inductor conductor on the semiconductor substrate, an insulating film is formed on the entire surface of the semiconductor substrate by a chemical liquid phase method. , A part of this insulating film is removed by etching or laser light irradiation to make a hole,
An inductance variable element characterized in that terminals are attached by sealing the holes to the extent that they rise up on the surface with solder.