JPH0689976A - Semiconductor device - Google Patents

Abstract

(57) [Abstract] [Purpose] A semiconductor device having an inductor having a solenoid structure that can be built in a chip of a MOS type LSI as a part of a process and an inductor exhibiting high inductance, and a semiconductor device having adjustable inductance. Offer. In a semiconductor device having a MOS structure, an inductor having a solenoid structure is built in the semiconductor device, and preferably, a high magnetic permeability material is used as a magnetic core inside the inductor having the solenoid structure, A semiconductor device preferably having a closed circuit magnetic core, and a semiconductor device having a magnetic flux controller connected to one of two solenoid structures sharing the closed circuit magnetic core.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device such as an LSI chip having a MOS structure in which an inductor having a solenoid coil structure is formed.

[0002]

BACKGROUND OF THE INVENTION Inductance components, or inductors, are used to add delay to a circuit or to change the impedance of a circuit.

By the way, conventionally, there is no example in which the inductor is realized in the LSI chip, and the inductor is manufactured separately from the LSI chip and housed in the same package. That is, in the LSI chip, capacitance can be obtained by using a transistor, but inductance is not obtained.

For example, in general, an active element in the microwave band has a low input / output impedance, and when it is mounted in a circuit, particularly in the case of a high frequency power transistor, an LC circuit is provided inside the transistor container. By incorporating an impedance transformer, the impedance seen from the terminal of the container of the transistor is increased to facilitate mounting in a circuit. The LC composite circuit for this purpose is
No. 10067 and JP-A No. 53-38274.

[0005]

By the way, the LC composite circuit disclosed here is an MO formed on a semiconductor substrate.
It can be obtained as one chip in which a spiral inductance is formed on the same semiconductor substrate in the vicinity of the S capacitance. For example, when this LC composite circuit is used as an impedance transformer of a high frequency power transistor, Since it was not built as a part, it had to be made separately from the transistor, and it was necessary to mount it in the container of the transistor. Further, since the spiral inductance of the LC composite circuit disclosed herein is formed in a planar shape on the semiconductor substrate, it is not possible to increase the inductance by using a core material having a high magnetic permeability. When an inductance component cannot be obtained and a high inductance is required, there is a problem that it is necessary to supplement with an external circuit.

A main object of the present invention is to solve the above problems of the prior art and to provide a semiconductor device having a solenoid structure inductor which can be built in a MOS type LSI chip as a part of a process. .

Another object of the present invention is to provide a semiconductor device having an inductor exhibiting a high inductance in addition to the above objects.

Another object of the present invention is to provide, in addition to the above object, a semiconductor device having an inductor capable of correcting and temporarily changing the inductance and adjusting it to a desired value.

[0009]

In order to achieve the above main object, the present invention is a semiconductor device having a MOS structure, wherein an inductor having a solenoid structure is built in the semiconductor device. A device is provided.

In order to achieve the above-mentioned other object, the present invention is the above semiconductor device, wherein the inductor having the solenoid structure further has a high magnetic permeability material as a magnetic core therein. Is provided. Here, it is preferable that the magnetic core forms a closed circuit.

Further, the present invention provides the above semiconductor device, further comprising a magnetic flux control section and a magnetic flux controlling solenoid sharing the closed circuit magnetic core.

Here, at least one of the solenoid structure of the inductor and the magnetic flux controlling solenoid is MO.
It is composed of a plurality of strip-shaped gates formed on an S-structure gate oxide film, and a plurality of metal wiring materials for sequentially connecting one end of these gates to the other end of the next gate. Is preferred.

[0013]

According to the semiconductor device of the present invention, the MOS type LS is used.
As part of the manufacturing process (process) of I, an inductor (coil) having a solenoid structure is built in the LSI chip. Therefore, the inductance can be obtained in the LSI chip, and the delay circuit and the tuning circuit can be easily and inexpensively configured in the chip together with the capacitance without using an external circuit. Therefore, since the circuit manufactured in this manner is manufactured as a part of the manufacturing process, the circuit configuration can be simplified and the cost can be reduced.

Further, the semiconductor device of the present invention has a core (magnetic core) made of a high magnetic permeability material in the center of an inductor (coil) having a solenoid structure formed as a part of the process, and is incorporated in an LSI chip. Despite being built in, high inductance (induction coefficient) can be achieved. Therefore, it is not necessary to use an external circuit to realize high impedance. Furthermore, in a semiconductor device according to another aspect of the present invention, since the core has a closed circuit and magnetic lines of force do not appear from both ends like a coil having a finite length solenoid structure, data is erased, changed or delayed. Etc. does not occur, and there is no fear of adversely affecting the transistors in the LSI chip.

Furthermore, in a semiconductor device according to another aspect of the present invention, another solenoid that shares a closed circuit core of an inductor having a solenoid structure is configured, and a magnetic flux control unit, such as a current control circuit, is provided in the magnetic flux controlling solenoid. Is provided
The inductance of the solenoid-structured inductor can be controlled to a desired value by controlling the current flowing through the magnetic flux controlling solenoid to change the magnetic flux in the core.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor device according to the present invention will be described in detail with reference to the preferred embodiments shown in the accompanying drawings. FIG. 1 is a conceptual plan view of an embodiment of a semiconductor device according to the present invention.

As shown in FIG. 1, a semiconductor device 10 includes a large number of strip-shaped polysilicon gates 14 formed on a semiconductor substrate 12 and arranged in an array, and an insulating film formed on the polysilicon gates 14. Magnetic core (core) 16 formed so as to intersect with the array, and the polysilicon gates 1 in front and behind through an insulating film so as to surround the core 16.
4 is composed of a large number of metal wirings 18 sequentially connecting one end and the other end. In this way, a coil 20 having a solenoid structure is formed by the large number of polysilicon gates 14 and the metal wirings 18 that sequentially connect the polysilicon gates 14 to each other.

Although polysilicon (polycrystalline silicon) is used for the polysilicon gate 14 constituting the solenoid coil 20, the present invention is not limited to this, and the gate electrode wiring material or metal of the conventional LSI is used. Any material may be used as long as it is used as a wiring material. For example, the gate electrode wiring material is typically polysilicon, a refractory metal such as Mo or W, or Mo.
Examples thereof include silicides such as Si ₂ , WSi ₂ , TaSi ₂ , and TiSi ₂ . Typical metal wiring materials include, for example, aluminum (Al) and A.
Examples thereof include low resistance materials such as 1-alloy and copper (Cu). These wiring materials may be used alone or as a laminate. For example, a gate electrode may be formed by stacking silicide on the lower surface of polysilicon like a polycide gate. In addition to these wiring materials, a bonding wire material such as gold wire or Al wire may be used. Of these materials, considering the ease of manufacturing in the semiconductor manufacturing process, in particular, without adding or changing the process,
It is preferable that thin film forming techniques such as vapor deposition, CVD, and sputtering can be applied.

Solenoid coil 20 used in the present invention
Any metal wiring material may be used for the metal wiring 18 constituting the above as long as it is a metal wiring material used for a semiconductor device such as an LSI, or a bonding wire material used for mounting a semiconductor device may be used. Typical examples of the metal wiring material include Al, Al alloys, and Cu. Further, examples of the bonding wire material include gold, platinum, Al, Al alloy, Cu and the like. Also, these metal wiring materials,
Other than the bonding line material, the gate electrode wiring material may be used. Further, the above-mentioned gate electrode material, metal wiring material and bonding wire material may be laminated or connected and used. Among these materials, in view of easiness of manufacturing in the semiconductor manufacturing process, those to which the metallization process performed in the process can be applied are particularly preferable. In particular, those that can be formed by a metallization process without changing or adding processes are preferable.

As the material for the core 16 of the present invention, any conventionally used core material may be used, but a high magnetic permeability material is preferable. Representative examples of the high magnetic permeability material include silicon steel, permalloy, ferrite material, and amorphous high magnetic permeability material. Of these materials, amorphous metals that are easy to apply to semiconductor manufacturing processes are preferred,
Fe- (B, Si) -based amorphous alloy, Co- (F
e, Ni) -based amorphous alloy, Co- (Nb, Zr,
A sputtering deposition film of Ti) type amorphous alloy or the like is preferable. In the present invention, the core 16 is not essential, but in order to obtain high inductance,
It is preferable to have the core 16.

These solenoid coil 20 and core 16
The insulating film filling the gap between the SOG film and PSG
A film, a SiN film, or the like can be used.

Next, an example of a method of manufacturing the coil 20 having such a core-containing solenoid structure will be described based on an embodiment shown in FIG.

First, for example, a conventional L is formed on the P-type Si substrate 12.
Silicon dioxide for device isolation using OCOS method 2
2 is selectively grown to form a LOCOS oxide film 22, and then a thin gate oxide film 2 such as an SOG film is formed in the element region.
Grow 4 Subsequently, a low resistance polysilicon gate 14 is grown. Next, if necessary, a silicon nitride film (not shown) is deposited.

Next, the polysilicon gate 14 is formed in the device region.
To be formed as a strip-shaped gate electrode 14 on the
A strike (not shown) is patterned. After this,
Using dry etching as a mask, for example,
Cl as a reaction gas₂+ O ₂Pressure of 100mTo
Reactive dry etching under rr and RF power of 100W
The polysilicon gate 14 using an etching device.
A number of strip-shaped polysilicon gates on the wafer 1
4 is formed.

After that, the resist is removed by ashing using O ₂ plasma, and then phosphorus is self-aligned to 1 × 10 ¹³ ions / cm ² and an acceleration energy of 100.
Implantation is carried out under the condition of KeV to form a high resistance n ⁻ type diffusion layer 26.

Next, as the interlayer insulating film 28, a silicon dioxide film or a CVD-PSG film is grown and flattened, and then a Co— (Fe, Ni) -based amorphous alloy to be a core material is deposited by sputtering, By patterning and etching, cores 16 are formed on a large number of strip-shaped polysilicon gates 14 arranged in an array so as to intersect these gates. After that, a silicon dioxide film or CVD-PSG is formed so as to fill the core 16.
A film or the like is grown and planarized to form an interlayer insulating film 30.

Thereafter, anisotropic etching is used to form contact holes at both ends of a large number of strip-shaped polysilicon gates 14, and the contact holes are filled by a metallization method such as an Al (aluminum) electrode forming method to form polysilicon. A large number of Al layers such as vapor-deposited aluminum are formed on the interlayer insulating film 30 so that one end of the gate 14 is sequentially connected to the other end of the next polysilicon gate 14.
The wiring 18 is formed.

In this way, as a part of the manufacturing process of the MOS type LSI chip, the coil 20 having the solenoid structure can be built in the MOS type LSI chip. In the method described above, the coil 20 having the solenoid structure can be built in the chip at the time of manufacturing the MOS type LSI chip only by adding the step of making the core 16 to the manufacturing process of the MOS type LSI.

The method for manufacturing the coil 20, which is the most characteristic feature of the semiconductor device of the present invention, is not limited to the above-mentioned example, and MO
Any method may be used as long as the coil 20 can be formed as part of the S-type LSI manufacturing process. For example,
The core 16 may be directly formed by masking the formation and sputtering.

Further, as shown in FIGS. 3 and 4, S
A polysilicon gate 14 is formed on the i-substrate 12 by using an aluminum wiring material or a bonding wire (line) at the time of processing.
In place of the above, a plurality of linear bottom coil materials 18a having a predetermined length are formed so as to be arranged in an array, an insulating film 28 is formed next and flattened, a core 16 is formed on the insulating film 28, and an insulating film 28 is further formed. The coil material 18 is formed by laminating and flattening the contact holes, and forming contact holes at both ends of the coil material 18a and connecting the coil material 18a with the coil material 18a by an aluminum wiring material or a bonding wire.
b, 18b and these side coils 18b, 18
A semiconductor having the coil 20 of the solenoid structure of the present invention by connecting b using an aluminum wiring material or a bonding wire so as to sequentially connect one end of the coil material 18a and the other end of the next coil material 18a. The device may be manufactured.

Next, the polysilicon gate 14 shown in FIG.
Although the shape of the solenoid coil 2 is a strip shape, the present invention is not particularly limited, and the solenoid coil 2 can be combined with the metal wiring 18.
Any shape may be used as long as 0 can be configured, and for example, a linear shape may be used. Many of these polysilicon gates 1
The arrangement of 4 is not particularly limited, and may be arranged in parallel in a tilted state as long as they are arranged in an array. The large number of polysilicon gates 14 are preferably arranged in parallel, but are not particularly limited. Especially, MOS type LSI
It is more efficient to use an unused gate in the manufacturing process. Of course, as described above, the metal wiring material 18a such as Al wiring or bonding wire is directly connected to Si.
They may be arranged in an array on the substrate 12.

As described above, a large number of polysilicon gates 14 are formed.
Is connected to one end of the polysilicon gate 14 and the other end of the next polysilicon gate 14 by a metal wire 18, which constitutes a coil 20 having a solenoid structure. The metal wire 18 used is as shown in FIG. It may be formed by a vapor deposition method or a sputtering method as shown in FIG. 2, or as shown in FIG. 3 and FIG. 4, the Al wirings 18a, 18b, 18c which are previously made into metal wiring materials are sequentially connected Or the Al wirings 18a, 18
Part of b and 18c, for example, Al wirings 18a and 18c may be formed by using a wire material, and the rest, for example, Al wiring 18b may be formed by a vapor deposition method or a sputtering method. Lead wires 32, 32 are connected to both ends of the solenoid coil 20 thus obtained.

The cross-sectional shape of the high-permeability material used as the core 16 for improving the induction coefficient (inductance) is not particularly limited, but a columnar shape is preferable.

In the above example, the P type S substrate is used as the Si substrate.
An i-substrate is used to form an inductor (coil) in a P-channel MOS type LSI, but an n-type Si substrate is used to make an inductor (coil) in a solenoid structure in an n-channel MOS type LSI. Good.

Further, as shown in FIG. 5, when the coil 20 having the solenoid structure has a finite length, the magnetic force lines 3 are applied from both ends thereof.
6 appears. Therefore, depending on the environment in which the coil 20 is provided, operating conditions, etc., the transistors in the LSI chip may be adversely affected, and the data held in the transistors may be erased or changed, or the operation of the circuit may be delayed. It may have an impact. In such a case, a core (magnetic core) like the semiconductor device 38 shown in FIG.
By forming the closed circuit 34 with a high magnetic permeability material, it is possible to prevent the magnetic flux from going out and the magnetic field from appearing outside the solenoid coil 20.

Here, the shape of the closed circuit core 34 is preferably a rectangle (rectangle, square) or the like as shown in the figure from the viewpoint of ease of fabrication, but the present invention is not limited to this.
From the viewpoint of the effect of preventing leakage of magnetic flux, a circular shape is preferable, and a perfect circular shape is most effective and most preferable. However, it is difficult to make a circular core, and the area efficiency as an element also deteriorates. Therefore, in order to balance the ease of making and the effect, round the four corners of the rectangle, and then, for example, a quadrant with a small radius. Can also be Also, the size of the closed circuit core 34 is not particularly limited, and may be appropriately selected according to the required inductance and allowable area.

Although the solenoid coil 20 may be formed in a part of the closed circuit core 34 as shown in FIG. 6, it may be formed over the entire circumference of the closed circuit core 34. Good. Of course, when the solenoid coil 20 is formed over the entire circumference of the closed circuit core 34, a higher inductance can be obtained. However, if the number of turns of the coil 20 and the length of the coil 20 are appropriately selected according to the required inductance. Good.

In addition, by using the closed circuit core 34 in this way, it is possible to prevent or significantly reduce the generation of the leakage of the magnetic flux and the magnetic field, so that elements such as capacitors and transistors are provided inside the closed circuit core 34. It is also possible to improve the area efficiency of the device by increasing the area efficiency of the LSI chip.

The solenoid coil of the semiconductor device described above can be built in the LSI chip. However, since the number of turns and the core material are constant, its inductance is a fixed value, and the inductance is temporarily fixed. It cannot be changed to or adjusted to the target value. For this reason, in the semiconductor device 44 shown in FIG. 7, in addition to the solenoid coil 20 formed by the polysilicon gate 14 and the Al wiring 18 in the closed circuit core 34, similarly to other parts of the same closed circuit core 34. A magnetic flux controlling solenoid coil 40 formed by the polysilicon gate 14 and the Al wiring 18 may be formed, and the lead wires 32 at both ends thereof may be connected to a current control circuit 42 for controlling the magnetic flux.

In the semiconductor device 44 shown in FIG. 7, the magnetic flux controlling solenoid coil 40 is controlled by the current controlling circuit 42.
By changing the magnetic flux inside the closed circuit core 34 by applying a current to the inductor, the inductance in the inductor solenoid coil 20 can be changed, and the current flowing through the solenoid coil 40 is controlled by the current control circuit 42 for the purpose. A desired inductance can be obtained. If the inductance of the solenoid coil 20 of the inductor is continuously changed for a long time by the magnetic flux control unit having the current control circuit 42, the current control circuit 42 continues to flow the current to the magnetic flux control solenoid coil 40. , The power consumption will increase. For this reason,
The current control circuit 42 preferably controls the inductance of the solenoid coil 20 to be changed intermittently for a short time.

The present invention will be specifically described below based on specific examples. With Fe-Ni alloy is a maximum permeability of 70,000 to core material, the core section 10 [mu] m × 10 [mu] m as shown in FIG. 7 on the total area of about 10 cm ² chips,
Closed circuit core 34 that goes around a chip with a core length of 10 cm
Two solenoid coils 20 and 40 having 1400 turns are formed by the polysilicon gate 14 and the Al wiring 18, and an inductor having a solenoid structure is built on the chip. A current control circuit 42 was connected to one solenoid coil 40 to manufacture a semiconductor device of the present invention which can be used for controlling magnetic flux. The current flowing through one of the solenoid coils 40 is set to 0 by the current control circuit 42.
As a result of obtaining the inductance value of the other solenoid coil inductor 20 in which a current of 8 mA is flowing so that the current can be controlled to 20 mA, a change of 100 to 300 [H] was obtained. Here, the magnetic permeability μ used was 10,000 and the leakage magnetic flux was 50%. The inductance value of one of the solenoid coil inductors 20 was about 200 [H] when the current value I was 8 mA.

[0042]

As described above in detail, according to the present invention, an inductor (coil) having a solenoid structure can be built in an LSI chip as a part of a manufacturing process (process) of a MOS type LSI. Therefore, the inductance can be obtained easily and at low cost in the LSI chip,
It is possible to configure a delay circuit, an impedance transformation circuit, and the like together with the capacitance in the chip without using an external circuit. Therefore, since the circuit manufactured in this manner is manufactured as a part of the manufacturing process, the circuit configuration can be simplified and the cost can be reduced.

According to the present invention, in addition to the above effects,
Since the structure of the inductor (coil) is a solenoid structure, and a core (magnetic core) made of a high magnetic permeability material can be inserted in the center thereof, a high inductance (induction coefficient) can be obtained. Therefore, high impedance can also be realized by combining with the capacitance built in the chip.

Further, according to the present invention, by forming the core of the inductor (coil) of the solenoid structure in a closed circuit shape, in addition to the above-mentioned effects, the magnetic flux is confined in the core to prevent it from being emitted to the outside. You can Further, by making the core a closed circuit shape, particularly a circular shape, the magnetic field outside the coil of the solenoid structure can be reduced, and the influence on the magnetic field to the transistor in the LSI chip can be suppressed.

Further, according to the present invention, in addition to the above effect, the magnetic flux in the core is changed by the current control circuit provided in the magnetic flux control section so that the current flowing in the magnetic flux controlling solenoid coil sharing the closed circuit core is Since the inductance of the solenoid coil of the inductor can be controlled, the inductance can be adjusted to a desired value.

[Brief description of drawings]

FIG. 1 is a conceptual top view of an embodiment of a semiconductor device according to the present invention.

FIG. 2 is a schematic cross-sectional view of another embodiment of the semiconductor device according to the present invention.

FIG. 3 is a schematic top view of another embodiment of the semiconductor device according to the present invention.

FIG. 4 is a schematic cross-sectional view of another embodiment of the semiconductor device according to the present invention.

FIG. 5 is a conceptual top view showing an example of the operation of the semiconductor device of the present invention.

FIG. 6 is a schematic top view of another embodiment of the semiconductor device of the present invention.

FIG. 7 is a schematic top view of another embodiment of the semiconductor device of the present invention.

[Explanation of symbols]

 10, 38, 44 semiconductor device 12 Si substrate 14 polysilicon gate 16 core 18 metal wiring 18a, 18b, 18c Al wiring 20 solenoid (structure) coil 22 LOCOS oxide film 24 gate oxide film 26 diffusion layer 28, 30 (interlayer) insulation Membrane 32 Lead wire 34 Closed circuit core 36 Magnetic field line 40 Flux control solenoid coil 42 Current control circuit

Claims (6)

[Claims] 1. A semiconductor device having a MOS structure, wherein an inductor having a solenoid structure is built in the semiconductor device. 2. The semiconductor device according to claim 1, wherein the inductor having the solenoid structure further has a high magnetic permeability material as a magnetic core therein. 3. The semiconductor device according to claim 2, wherein the magnetic core forms a closed circuit. 4. The semiconductor device according to claim 3, further comprising a magnetic flux control section and a magnetic flux control solenoid that shares the closed circuit magnetic core. 5. The magnetic flux controlling solenoid comprises a plurality of strip-shaped gates formed on a gate oxide film of a MOS structure, one end of these gates and the other end of the next gate in order. The semiconductor device according to claim 4, comprising a plurality of metal wiring materials connected to each other. 6. The solenoid structure of the inductor is an MO
It is composed of a plurality of strip-shaped gates formed on an S-structure gate oxide film, and a plurality of metal wiring materials for sequentially connecting one end of these gates to the other end of the next gate. The semiconductor device according to claim 1.