JP3382215B2 - Planar magnetic element, method of manufacturing the same, and semiconductor device having flat magnetic element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar magnetic element such as a planar inductor or a planar transformer, and a method for manufacturing the same.
The present invention relates to a semiconductor device including a flat type magnetic element .

[0002]

2. Description of the Related Art In recent years, miniaturization of various electronic devices has been actively promoted, and along with this, the volume ratio of the power source portion in the entire device tends to increase. This is because various circuits are LSI
While miniaturization and integration of magnetic components such as inductors and transformers, which are indispensable circuit elements in the power supply unit, have been delayed.

In order to miniaturize magnetic elements such as inductors and transformers, attempts have been made to make these magnetic elements flat. Conventionally, as a planar inductor,
There is known a structure in which both sides of a spiral plane coil are sandwiched by insulating layers, and further both sides are sandwiched by magnetic materials. Similarly, as a flat type transformer, a spiral side flat coil on the primary side and a spiral side flat coil on the secondary side are formed via an insulating layer, both sides of which are sandwiched by insulating layers, and further both sides of these are sandwiched. A structure sandwiched between magnetic materials is known. The spiral plane coil may be composed of one layer of spiral coil conductors, or two layers of spiral coil conductors formed on both sides of an insulating layer and connected so that the generated magnetic fields are in the same direction. But it's okay.

Regarding this planar magnetic element, "High-Fr
equency of a Planar-Type Microtransformer and Its
Application to Multilayered Switching Regulators ";
K.Yamasawa et al., IEEE Trans. Mag. Vol. 26, No. 3, May
Although it was reported in 1990, pp.1204-1209, there is a large loss in operation. In addition, regarding a similar planar magnetic element,
It is disclosed in US Pat. No. 4,803,609.

Further, in order to miniaturize these plane type magnetic elements, it is considered to manufacture them by using a thin film process like the semiconductor manufacturing process.

The planar inductor having such a structure needs to have a sufficiently high Q value in the frequency band used. In the flat transformer, the transformer gain is set to a predetermined value (gain> 1 for step-up, gain <1 for step-down).
And it is necessary to reduce the voltage fluctuation rate.

The Q of the planar inductor is represented by Q = ωL / R. Here, R is a coil resistance and L is an inductance.

The gain G of the plane transformer is expressed by G = k (L2 / L1) ¹ / 2.multidot. {Q / (1 + Q2) ^1/2 }. Where k is the primary coil of the transformer and 2
Coupling coefficient of the secondary coil, L1 and L2 are inductances on the primary and secondary sides, Q is given by Q = ωL1 / R1, and R1 is 1
This is the coil resistance on the secondary side. The gain of the transformer is Q << 1
When Q >> 1, it becomes a constant value k (L2 / L1) ^1/2 regardless of Q.

In order to increase the Q of the inductor and the gain G of the transformer and suppress the voltage fluctuation, it is necessary to reduce the coil resistance and increase the inductance as much as possible.

However, in the conventional flat type magnetic element manufactured by the thin film process, since the cross-sectional area of the coil conductor forming the flat coil cannot be made large, the coil resistance is very large, the inductance is small, and the leakage magnetic flux is large. As a result, the inductor has a low Q, and the transformer has a low gain G and a large voltage fluctuation rate, which is a major obstacle to practical use.

Considering the performance of only the inductor, the spiral type is advantageous as the plane coil pattern because of its large inductance and the high quality factor Q. Actually, as shown in FIG. 1, a flat inductor using an amorphous magnetic alloy foil obtained by cutting an amorphous ribbon obtained by quenching into an appropriate size and a square spiral flat coil was manufactured, and a
-It is applied to the output choke coil of the 2W class step-down chopper type DC-DC converter (the 1989 national conference of the Institute of Electrical Engineers of Japan). In this case, as shown in FIG. 2A, a direct current corresponding to the load current and an alternating current due to the switching of the semiconductor switch flow through the inductor. As the DC current increases, the operating point of the magnetic material reaches the saturation region of the BH curve,
Since the rate of increase in magnetic permeability decreases, the inductance sharply decreases (see FIG. 2B). FIG. 3 shows this state, and the AC overcurrent at this time may give an excessive stress to the semiconductor switch and destroy the element.

The relationship between the DC superposition current and the inductance is called the DC superposition characteristic. It is desired that the choke coil has a constant electric characteristic such as inductance even when the DC current is superposed. FIG. 4 shows a typical DC superposition characteristic.

In such a choke coil, a direct current corresponding to the load current and an alternating current due to the switching of the semiconductor switch flow. The choke coil is required to have a DC superposition characteristic that electric characteristics such as inductance are as constant as possible even when a large DC current is superposed. However, when the operating point of the magnetic material reaches the saturation region of the BH curve as a result of the increase in the DC superimposed current, the rate of increase in magnetic permeability decreases, so that the inductance sharply decreases. Further, the overcurrent at this time may give an excessive stress to the semiconductor switch, and may destroy the element.

Particularly, in the planar inductor, the coil conductor and the magnetic body are very close to each other, and the magnetic field is large even with a small coil current, so that the magnetic body is likely to be magnetically saturated. As a specific example thereof, a spiral plane coil made of an Al-Cu alloy, and insulating layers provided on both surfaces thereof,
The planar inductor composed of the magnetic layers provided on both surfaces of these is described below. In this planar inductor, the coil conductor forming the spiral planar coil has a width of 50 μm, a thickness of 10 μm, an interval between conductors of 10 μm, a winding number of 20, an insulating layer has a film thickness of 1 μm, a magnetic film has a film thickness of 5 μm, and a saturation magnetic flux density BS = 15 kG. , Magnetic permeability μs = 5000.

Al-C used as a coil conductor
Assuming that the allowable current density of the u alloy is 5 × 10 ⁸ A / m ² , the allowable current Imax is 250 mA. However, when the relationship between the coil current and the magnetic field in-plane generated by the coil current was examined, when the coil current was 48 mA or more, the magnetic substance was magnetically saturated. That is, when this planar inductor is used as a choke, the maximum DC superimposed current is limited to 48 mA. This value is only about 1/5 of the coil allowable current, and it can be seen that the magnetic substance is easily saturated.

The problem of the DC superposition characteristic is not limited to the case of the inductor for the choke coil, but is important even in the case of the transformer. For example, in a forward-type or flyback-type DC-DC converter transformer, since a unipolar pulse voltage is applied to the primary coil, a sudden decrease in inductance due to magnetic saturation still poses a problem. Also,
In the push-pull type DC-DC converter, the voltage applied to the transformer is positively and negatively symmetrical in principle, so that it is apt to be considered that the influence of magnetic saturation is slight, but due to variations in the characteristics of the switching transistor, etc. Since the positive and negative ON times fluctuate and the transformer is demagnetized, a sudden decrease in inductance due to magnetic saturation still poses a problem.

In such a problem, the direct current superposition characteristic can be improved by reducing the influence of magnetic saturation of the magnetic material forming the planar inductor or transformer. Effective utilization of magnetic anisotropy is being sought.

As the plane coil, various coil patterns such as a zigzag folded type, a spiral type, and a zigzag folded-spiral combined type are used. Among these coil patterns, the spiral type has the largest inductance value. Therefore, in obtaining the same electrical characteristics, the coil pattern can be made smaller than other coil patterns. However, in the case of the spiral type, in order to provide an external lead terminal, it is necessary to connect a two-layer spiral coil with a through-hole conductor or separately provide a terminal lead conductor. Is a little complicated.

For an electronic circuit engineer, it is preferable that the magnetic element used in the electronic circuit has a trimming function for circuit adjustment. Conventionally, as a magnetic element with a trimming function, for example, a part of the magnetic circuit is provided with a screw part capable of adjusting the distance to the coil magnetic core, and the inductance can be continuously varied by changing the gap of the magnetic circuit. Is used. However, the performance of conventional planar magnetic elements is
It depends significantly on the structural parameters of the device. Since these factors are greatly affected by the device manufacturing process, the variations in device characteristics after manufacturing were very large. In addition, it is difficult to add a trimming function to the conventional planar magnetic element due to structural problems.

Now, regarding magnetic elements designed to have a small leakage magnetic field and a large current capacity, "Issues Related to 1-10-MHz Transformar Desig
n "; AFGoldberg et al., IEEE Trans. Power Electroni
cs Vol.4, No.1, January, 1989, pp.113-123.

As described above, the flat type magnetic element is expected to greatly contribute to miniaturization and integration, but it is far from practical use, and it is not suitable for a circuit portion including an LC circuit represented by a power source portion. Miniaturization has not been achieved.

Since the laminated planar inductor essentially has a closed magnetic circuit, (1) it does not affect the operation of other devices when integrated with other devices (no leakage flux) ( 2) It is difficult to satisfy that the inductance is large. For this reason, miniaturization and integration of the circuit section including the LC circuit represented by the power supply section has not been achieved. There is a strong demand for demands on these points, that is, for practical use of a planar magnetic element satisfying required performances.

On the other hand, due to structural problems, it has been difficult to add a trimming function to the conventional planar magnetic element.

[0024]

An object of the present invention is to provide a planar magnetic element.

The first purpose is that small size integration is possible.

The second purpose is to obtain a large inductance.

The third purpose is to reduce external leakage of magnetic flux.

The fourth object is that the high frequency characteristic and the DC superimposed current characteristic are excellent.

The fifth object includes an inductance having a large current capacity.

A sixth object is that the terminal can be easily drawn out.

The seventh object is to have a trimming function capable of adjusting the electrical characteristics from the outside.

[0032]

In the present invention, the above objects are achieved by the means shown below. Further, the respective means can be used in combination, not independently, and by combining them, further improvement in performance and convenience of handling can be achieved. In addition, in the following explanation
Now, the planar magnetic element will be mainly described.
Can be applied to semiconductor devices equipped with magnetic elements of
Of course. A device equipped with the magnetic element according to the present invention is used.
For example, there is a DC-DC converter, etc.
What if the magnetic element according to the invention is used?
It can also be applied to various configurations. Also, magnetic elements and other
Circuits and elements may be configured on-chip,
It may be built in the same package.

The first means of the present invention is to laminate an insulator and a magnetic material on a spiral flat coil having a groove aspect ratio (width of coil conductor / interval between coil conductors) between adjacent coil conductors of 1 or more. It is characterized by being done.

The second means of the present invention is characterized in that the conductor constituting the coil has a conductor aspect ratio (width of coil conductor / height of coil conductor) of 1 or more.

The third means of the present invention is, in a laminated type planar inductor comprising a spiral planar coil sandwiching a magnetic material, the outer dimension w of the magnetic material is 2α (α = [μs · g・ T / 2] ^1/2 ; μs is the magnetic permeability, t is the thickness of the magnetic substance, and g is the distance between the upper and lower magnetic substances).

According to a fourth aspect of the present invention, in a magnetic element in which an upper surface and a lower surface of a planar coil are sandwiched by magnetic layers, the magnetic layer is uniaxially magnetically different in a direction orthogonal to a direction of a magnetic field generated by the planar coil. It is characterized by having an orientation.

According to a fifth aspect of the present invention, in a magnetic element having a structure in which a plane coil is sandwiched between magnetic layers, the plane coil has a plurality of external connection terminals and has a plurality of external dimensions. It is characterized by comprising a one-turn plane coil, and the one-turn plane coil is arranged on the same plane.

According to a sixth aspect of the present invention, the magnetic layer constituting the closed magnetic path is surrounded by the conductor layer, and the surface current flowing through the conductor layer magnetizes the magnetic layer in the closed magnetic path direction. It is characterized in that it is configured as follows.

[0039]

The operation of each means of the present invention will be described for each means.

The planar magnetic element according to the first means of the present invention reduces the coil resistance, and as a result, Q
However, the gain and the voltage fluctuation rate can be improved in the transformer.

In the flat type magnetic element according to the second means of the present invention, the allowable current can be increased by increasing the cross-sectional area of the conductor forming the coil.

The planar magnetic element according to the third means of the present invention utilizes the fact that the external magnetic field is reduced by increasing the external size of the magnetic body. The optimum design aims to reduce the leakage flux to the outside of the inductor and increase the inductance.

The flat magnetic element according to the fourth means of the present invention effectively utilizes the uniaxial magnetic anisotropy of the magnetic material to make it difficult to cause magnetic saturation, and thus has excellent DC superposition characteristics and high frequency characteristics. There is.

The planar magnetic element according to the fifth means of the present invention has a structure having a plurality of external connection terminals, so that it is extremely easy to electrically connect to an external circuit and the electrical characteristics can be trimmed from the outside. As a result, it becomes a very useful magnetic component for application of the element.

The flat type magnetic element according to the sixth means of the present invention has a substantially complete inner iron structure so that there is no leakage magnetic field, and the effective conductor has a large cross-sectional area, resulting in a large current capacity. Can be taken.

[0046]

The present invention will be described in detail below. here,
For convenience, each means will be described independently, but as described above, it is possible to combine each means to form a magnetic element. The materials are almost the same for all the means, so they are collectively described at the end of this description.

First, the first means will be described with reference to FIGS.

FIG. 5 is an exploded perspective view of the plane inductor according to the first means. In FIG. 5, the magnetic layer 30A is arranged on the semiconductor substrate 10 via the insulator layer 20A, and the spiral coil 40 made of a spiral coil conductor is arranged on the magnetic layer 30A via the insulator layer 20B. Then, the insulating layer 20C, the magnetic layer 30B, and the protective layer 50 are arranged in this order on this. FIG. 6 is a sectional view taken along line 6-6 of FIG. 5, and the same members are designated by the same reference numerals.

FIG. 7 is an exploded perspective view of the plane transformer according to the first means. Here, the case where the number of turns of the primary coil and the secondary coil is the same is shown. In FIG. 7, the magnetic layer 30A is arranged on the semiconductor substrate 10 via the insulator layer 20A, and the primary side spiral coil 40A made of a coil conductor is provided on the magnetic layer 30A via the insulator layer 20B. 2 arranged on the coil 40A with the insulator layer 20C interposed therebetween.
A secondary spiral coil 40B is provided. Further, the insulating layer 20D, the magnetic layer 30B, and the protective layer 50 are arranged in this order on the insulating layer 20D. 8 is a sectional view taken along line 8-8 of FIG. 7, and the same members are designated by the same reference numerals.

Although FIG. 5 to FIG. 8 show the case where a semiconductor such as silicon is used as the substrate, when the glass substrate is used, it is an insulator itself, so that it is used as the base of the magnetic layer 30A. It is not necessary to provide the insulator layer 20A.

In the first means, in both the planar inductor of FIG. 5 and the planar transformer of FIG. 7 exemplified above, the groove aspect ratio h / b of the groove portion between the coil conductors forming the spiral coil (h is Coil conductor thickness,
b is formed such that the distance between coil conductors is 1 or more.

Thus, a high groove aspect ratio h of 1 or more is obtained.
Various methods are conceivable for realizing the groove having / b. As one method, a method in which a conductor is deeply grooved in a spiral shape by dry etching and then an insulator is embedded in a void portion can be considered. As another method, a method in which a conductor is embedded after forming an insulator pattern in a region corresponding to a groove portion between coil conductors by dry etching can be considered.

In the former method, the case where an insulator is embedded in the entire groove and the case where a cavity is formed can be considered. Here, the case where an insulator is embedded in the entire groove is shown, and the case where a cavity is formed in the groove will be described at the time of describing the second means of the present invention. In this method, a conductor for a plane coil is formed, a mask material is formed in a coil pattern on the conductor, and the exposed conductor is etched by a dry etching method to form a deep groove having a groove aspect ratio h / b of 1 or more. To form. Specifically, an ion beam etching method having high directivity, an ECR plasma etching method, a reactive ion etching method, or the like is used. At this time, an appropriate method is selected so that vertical anisotropic etching can be realized by sufficiently securing the etching selection ratio between the mask material or the base and the conductor.

When the insulator layer is formed on the formed coil conductor having the groove portion having the high groove aspect ratio h / b, the groove portion is filled with an insulator having a low dielectric constant and the upper surface is flattened. It is preferable. SiO as an insulator
_When using an inorganic material such as ₂ or Si ₃ N ₄ , the CVD method,
A sputtering method such as a reactive sputtering method or a bias sputtering method is appropriately selected. When an organic material is used as the insulator, a polyimide (including a photosensitive material) having a low dielectric constant is preferable, but a resist or the like may be used.
After spin-coating these with a solvent, an insulating layer is formed by an appropriate curing treatment. Regardless of whether it is an inorganic substance or an organic substance, an insulator is embedded in the groove portion of the coil groove, and the upper surface thereof is flattened by an etch-back process.

In the latter method, an insulating layer is formed, a resist pattern is formed on a region of the insulating layer corresponding to the groove portion of the coil groove, and the exposed insulating layer is etched by a dry etching method. The insulator is left in a coil pattern in the region corresponding to the groove. Next, with the resist left, a conductor is embedded by a method such as a sputtering method, a CVD method, or a vacuum deposition method to form a spiral coil.
After embedding the conductor, the resist and the conductor above it are removed by the lift-off method.

Which of the above-mentioned methods is adopted is appropriately selected according to the pattern of the spiral plane coil.

The effect of the magnetic element produced by the first means of the present invention will be described.

FIG. 9 is a graph showing the relationship between the groove aspect ratio h / b of the conductor forming the planar inductor and the coil resistance R and the inductance L. In FIG. 9, for the inductance L, the product of the magnetic permeability (μs) and the thickness (t) of the magnetic substance μs · t is used as a parameter, and μs · t = 50.
The case of 00 μm or 1000 μm is shown.
As is clear from FIG. 9, the inductance L is almost constant and almost independent of the groove aspect ratio h / b. On the other hand, the coil resistance sharply decreases as the groove aspect ratio h / b increases, and becomes almost constant at 5 or more.

FIG. 10 shows the relationship between the groove aspect ratio h / b and L / R of the conductor forming the planar inductor. L / R is an amount proportional to the Q of the inductor, Q = 2
There is a relationship of πfL / R (f is frequency: Hz). Figure 10
Then, use the magnetic permeability (μs) parameter, and μs = 1
The case of 0 ⁴ or 10 ³ is shown. As is apparent from FIG. 10, L / R increases as the groove aspect ratio h / b increases, but becomes almost constant at 5 or more.

In the following table, the groove aspect ratio h / b is 0.3,
The Q at 5 MHz is shown for planar inductors made with settings of 0.5, 1.0, 2.0, or 5.0. In the following table, the product of magnetic permeability (μs) and thickness (t) μs · t is used as a parameter, and μs · t = 5000μm
Alternatively, the case of 1000 μm is shown. As is clear from Table 1, Q when the groove aspect ratio h / b is 1
Is about 3.5 times 0.3, and about 1.5 is 0.5
Double. In this way, by setting the groove aspect ratio h / b to 1 or more, a high Q can be realized and the performance of the planar inductor can be greatly improved.

[0061]

[Table 1]

FIG. 11 shows the relationship between the groove aspect ratio h / b of the conductor forming the plane transformer and the Q and transformer gain G of the primary coil of the plane transformer. As is clear from FIG. 11, by increasing the groove aspect ratio h / b to 1 or more, Q can be increased, and as a result, the trans gain G can be increased.

Further, when forming a magnetic element, the choice of the material that influences the performance thereof becomes a major issue, and the choice of the material will be described at the end of this description.

As a second means, the conductor aspect ratio h /
An example is shown in which d (h is the height of the coil conductor and d is the width of the coil conductor) is set according to the second means.

FIG. 12A shows an exploded perspective view of an example in which the conductor aspect ratio h / d and the groove aspect ratio h / b are set,
The planar coil 40 is directly formed on the substrate 10. 12B is a sectional view taken along line 12B-12B in FIG.
Indicates a coil conductor. The conductor can be formed by using a manufacturing method that is used for forming wiring in a normal semiconductor process. The wiring pitch is naturally limited. As the pitch width becomes narrower, the size can be reduced, but it becomes difficult to achieve a high conductor aspect ratio. Therefore, it is desirable to determine the most suitable pitch and conductor aspect ratio h / d according to the desired characteristics and manufacture. Although the numerical value is not particularly determined in terms of high conductor aspect ratio, it is approximately 1 or more, that is,
It is preferable to use a conductor having a high conductor aspect ratio h / d with a line height equal to or larger than the line width, and a high groove aspect ratio h / b from the viewpoint of miniaturization. Although there is no particular limitation in terms of numerical value, from the viewpoint of a microcoil, both the conductor width and the groove distance are 10 μm.
It is considered that the effect is substantially exhibited when it is about m or less.

Now, regarding the production of a conductor having a high conductor aspect ratio h / d, considering that it is formed by etching, a narrow and deep groove will be carved. Therefore, it is necessary to use a conductor film having good selectivity. For that purpose, it is desirable to use, as the conductor layer, an oriented crystal film formed so that the easily etched surface is parallel to the conductor formation surface. Of course, a single crystal is better.

Although the inductance may be insufficient due to downsizing even if the above-mentioned measures are taken, the reactance is ωL (ω is a driving angular frequency), so it is necessary to compensate by increasing the driving frequency. You can In recent years, the switching frequency has become higher and the low reactance due to miniaturization can be sufficiently compensated. For example MH
In a high frequency range of about z, even a low inductance of about nH works well as an inductor.

Here, when the conductors having a high conductor aspect ratio h / d are brought close to each other, the facing area of the adjacent grooves is increased, and the synergistic effect of the fact that the distances are short results in an increase in the line capacitance. It is also possible to configure the LC circuit by utilizing this. However, in general, the LC oscillation frequency (cutoff frequency) becomes small, the inductor cannot operate, and it may not be possible to cope with higher frequencies. Therefore, it is desired to reduce the line capacitance as much as possible. An insulator such as SiO ₂ is formed on the miniaturized coil conductor as used in a normal semiconductor process. Instead of the insulator layer 20, the spaces between the lines are hollowed and the spaces between the lines are formed. By reducing the dielectric constant, the line capacitance can be reduced. in this case,
When forming the insulating film on the planar coil, the film may be formed under the condition that a cavity is formed between the lines. Therefore, the inside of the cavity may be in a state close to vacuum, or the source gas used for forming the insulating film may exist. In any case, the dielectric constant is much lower than that in the case where a normal solid insulator is present, and the line capacitance is surely reduced.

As a method for realizing such a cavity, the CVD method used in a normal semiconductor element forming process may be applied. Good adhesion in general semiconductor processes,
Although an insulating film such as SiO ₂ is formed over the entire surface, in the case of the second means, the insulating film is formed mainly on the upper surface of the coil, the space of the groove is maintained, and as a result, the lid is formed on the upper part of the space. It suffices to set the conditions that are set. Specifically, the conditions may be set so that the film deposition rate is determined by the transport rate of the source gas (feed rate limiting). This situation is shown in Figure 1.
3 shows. The source gas 82 is directly supplied to the upper surface of the coil formed of the conductor 42 formed on the substrate 10. However, since the source gas 82 is hard to reach the lower part of the groove, the growth of the film 80 on the upper surface SiO _2. Is faster, Fig. 13A → Fig. 13
The reaction proceeds in the order of B → FIG. 13C → FIG. 13D, and as a result, the cavity 70 as described above is formed. Further, as shown in FIG. 14, cavitation can also be realized by sputtering insulator particles 84 on the upper surface of the coil conductor 42 in an oblique direction (θ). However, considering the flatness of the insulating film after cavitation, it is desirable to form it by the CVD method.

The effect of reducing the line capacitance due to the hollowing will be described by approximating the parallel plate capacitor shown in FIG.

60 between r (m) × t (m) parallel electrode plates
A, 60B (distance s0) is filled with the insulator 20 having a non-dielectric constant ε, the capacity (C0) is C0 = ε0 · ε · t / s0 (F / m) (where ε0 is a vacuum dielectric Rate). On the other hand, if the capacitance when there are cavities of uniform width (s) in the space between the parallel electrode plates is C, then C / C0 = 1 / [k (ε-1) +1] (where k is It represents the ratio (s / s0) occupied by cavities.

FIG. 16 shows the k dependence of C / C0 when the insulator is SiO ₂ (relative permittivity: about 4). It can be seen that when the ratio of the cavity of the groove is set to approximately 1/3 or less, the capacitance becomes 1/2 or less as compared with the insulator-filled state. When gas is present in the cavities (or in a state close to vacuum), it is practical to make the cavities ⅓ or more, although it depends on the type of the insulator.

The inductor is constructed based on the coil as described above. However, since the coil alone has a small inductance, it is desirable to provide the magnetic layer 20 close to the coil so as to form the magnetic core. . In this case, in order to reduce the leakage magnetic field as much as possible, it is preferable to have a structure in which the upper and lower surfaces of the coil are sandwiched by magnetic materials. This structure is shown in FIG. A magnetic layer 30A is formed on an insulative substrate 10 such as a Si substrate having an oxide film on its surface, a coil composed of a planar coil 40 is formed via an insulator layer 20A, and an insulator is further formed thereon. The magnetic layer 30B is formed via the layer 20B. In this structure, the magnetic layers 30A and 30B also serve as a magnetic shield, and the leakage magnetic field to the outside can be almost eliminated. Therefore, it is possible to minimize the size of the components when considering the total because the influence on the elements arranged in the surroundings is minimized. In some cases, the magnetic core may not be provided and the coil may be used as an air-core coil, or the magnetic layer may be provided only on one side. Note that the structure shown in FIG. 18 shows a planar coil that is multilayered by interposing an insulating layer 20C. By doing so, the number of turns can be increased, so that a high inductor can be achieved.

The coil according to the present invention may have various shapes such as a spiral shape as shown in FIG. 19A and a meander shape as shown in FIG. 19B. The spiral is more advantageous in terms of inductance.

Further, in this case, since the conductor has a considerably large film thickness as compared with that used in a normal semiconductor, the bonding strength with the substrate may become a problem. In that case,
As shown in FIG. 20, the conductor 42 may be formed on the substrate 10 via a thin layer such as Cr as the bonding layer 25. The method using the bonding layer 25 is the other means, that is, the first, third,
The fourth and fifth means have the same coil shape, and can be similarly applied. In addition, the conductor has the most suitable pitch and conductor aspect ratio h /
It is preferable to determine and manufacture d. From the viewpoint of miniaturization, it is preferable that the interval between the adjacent conductors is equal to or smaller than the width of the conductor. Although these dimensions are not particularly limited, the spacing between adjacent conductors is preferably 10 μm or less in order to obtain a substantial effect. This can be applied to other means as well as the bonding layer.

Although the above description has been made mainly for the case of a single inductor, it is also possible to construct a microtransformer by combining two coils, for example. An example of this structure is shown in FIG. A magnetic layer 30A, an insulator layer 20A, a plane coil 40A, an insulator layer 20B, a plane coil 40B, an insulator layer 20C, and a magnetic layer 30B are provided on a substrate 10 such as a Si substrate having a silicon oxide film formed on its surface. Are sequentially stacked. For example, the plane coil 40A constitutes a primary coil and the plane coil 40B constitutes a secondary coil. The primary and secondary coils are set to the desired turns ratio. In such a configuration, the magnetic layers 30A and 30B are preferably provided so as to sandwich the laminated body of the primary coil and the secondary coil. Further, the primary coil and the secondary coil may be formed on the same plane, as shown in FIG. 22A which is a conceptual view of the coil viewed from above. The figure shows a state in which the primary coils and the secondary coils are alternately combined and are present on the same plane. However, they do not necessarily have to be combined alternately. In addition, as shown in FIG. 22B, the secondary coil may be present inside the primary coil.

Next, the third means will be described.

The third means will be described below in the case where the spiral coil 40 shown in FIG. 23 has one layer.
In the figure, the spiral coil 40 is arranged between the magnetic layers 30A and 30B with the insulator layers 20A and 20B interposed therebetween. Here, a0 is the dimension of one side of the outer shape of the spiral coil 40, w is the dimension of one side of the magnetic layers 30A and 30B, t is the thickness of the magnetic layers 30A and 30B, and g is between the magnetic layers 30A and 30B. Is the distance. Also in FIG.
In addition, the insulating layer 20C is provided between the magnetic layers 30A and 30B.
The spiral coils 40A and 40B are disposed through the insulating layer 20C having the through-hole conductor 42 between the planar coils 40A and 40B. Here, a0, w, t, and g indicate the dimensions of the same parts as in the case of FIG.

A third means is to optimize the relationship between the spiral outer dimensions and the magnetic outer dimensions as described above in the laminated flat inductor in which the spiral flat coil is sandwiched between the upper and lower magnetic bodies via the insulator. As a result, (1) the magnetic flux leakage to the outside is small and the magnetic shield effect is high, and (2) the inductance value can be increased. In this case, the planar inductor according to the third means may be formed on the semiconductor or glass substrate by the pre-thin film process, or by forming the spiral coil on another insulating substrate (various polymer materials such as polyimide), This may be sandwiched with a magnetic foil via a suitable insulating film.

When the planar inductor is integrated with other parts, there are problems of noise and circuit malfunction due to magnetic flux leakage. This is a problem in terms of making a hybrid IC, and becomes an even bigger problem in the case of monolithically integrating all circuit components including L and C into one chip.
That is, in the case of these integrated circuits, since the components are arranged close to each other, the influence of the leakage flux of the inductor becomes more serious. In a planar inductor,
In order to reduce the influence of such leakage magnetic flux, in the third means, the relative relationship between the outer dimension w of the magnetic layer and the outer dimension a0 of the spiral coil is optimized.

FIGS. 25A to 25C show the spiral coil 40.
The leakage flux 100 from the end of the magnetic material layer when the outer dimension w of the magnetic material layer 30 is variously changed with respect to the outer dimension a0 of
The magnetic flux leakage to the outside of the inductor can be drastically reduced by increasing w over a certain limit. Here, in FIG. 25A, almost a0 = w, and FIG.
From C to C, w is sequentially increased. Also in FIG.
[Fig. 3] is a drawing showing the magnetic field distribution of the spiral coil / magnetic material laminated type planar inductor. From this figure, from the end of the spiral coil α (α = [μs · g · t / 2] ^1/2 ; μ
s is the magnetic permeability of the magnetic material, t is the thickness of the magnetic material layer, and g is the distance between the upper and lower magnetic material layers), the magnitude of the magnetic field is reduced to about 0.37 times the value at the coil end. . That is,
It can be seen that if the outer dimension w of the magnetic layer is made larger than the outer dimension a0 of the spiral coil by 2α or more, the leakage magnetic flux to the outside of the inductor can be dramatically reduced. Here, the width of the coil conductor 42 is 70 μm, and the distance between the coil conductors is 10 μm.
μm, the gap between magnetic materials was 5 μm, and the coil current was 0.1 A.

FIG. 27 shows the magnitude of the magnetic flux leaking from the end of the magnetic layer (end of the inductor) to the outside with reference to the value when w = a0. When a planar inductor is monolithically formed in an integrated circuit, even a small leakage flux has a great influence on other devices, so that it is desirable that the outer dimension w of the magnetic layer be a0 + 10α or more. Thereby, the magnetic flux hardly leaks to the outside.

Now, when designing a planar inductor,
I want to make the inductance as large as possible. As in the third means, the inductance can be effectively increased by making the outer dimension w of the magnetic layer larger than the outer dimension a0 of the spiral coil by 2α (α is as described above) or more. FIG. 28 shows an example of changes in the inductance value when various values of w are changed, and w ≧ a0 + 2α
As a result, it is found that a value that is 1.8 times or more that when w = a0 is obtained.

The fourth means of the present invention will be described. In the following, the planar inductor will be described and the description of the planar transformer will be omitted. However, the planar transformer is structurally almost the same as the planar inductor except that two spiral planar coils on the primary side and the secondary side are laminated, and the effect obtained by the fourth means is also similar. .

First, as shown in FIG. 29, consider a planar inductor having a structure in which both sides of a rectangular spiral planar coil 1 are sandwiched between insulating layers 20 and both sides thereof are sandwiched between magnetic layers 30. Uniaxial magnetic anisotropy is introduced in the upper and lower magnetic layers 30 in the direction indicated by the arrow in the figure.

The direction of the magnetic field generated on the magnetic layer 3 when a coil current is passed through the spiral planar coil 40 of this planar inductor is shown in FIG. In the area A, the direction of the magnetic field generated by the coil coincides with the direction of uniaxial magnetic anisotropy (direction of easy magnetization axis). On the other hand, in the region B, the direction of the magnetic field generated by the coil and the direction of uniaxial magnetic anisotropy are orthogonal to each other, that is, the direction of the generated magnetic field and the direction of the hard axis of magnetization coincide.

FIG. 31 shows B- observed in the easy axis direction and the hard axis direction of the magnetic substance having uniaxial magnetic anisotropy.
The H curve is shown. On the other hand, the magnetic permeability is very high in the easy-axis direction, but it is easy to saturate, while it is hard to saturate in the hard-axis direction. Therefore, the area A in FIG. 30 is likely to be saturated, but the area B is less likely to be saturated because the direction of the generated magnetic field is in the difficult axis direction. As shown in FIG. 32A, when the magnetic field generated by the coil is large, the area A in FIG. 30 is saturated and the magnetic flux leaks into the space. At this time, as shown in FIG. 32B, most of the magnetic flux passes through the region B of FIG. After all, the magnitude of the inductance depends on the magnetic characteristics in the hard axis direction.

In the fourth means, the following three structures are adopted in order to solve the problem of magnetic saturation of the magnetic material. First, a plurality of magnetic layers having uniaxial magnetic anisotropy are formed on both surfaces of the spiral planar coil so that adjacent magnetic bodies have uniaxial magnetic anisotropy directions orthogonal to each other. It is laminated through layers. Second
Is a square planar coil with four triangular magnetic bodies, each of which has uniaxial magnetic anisotropy introduced in the direction parallel to the bottom, arranged so that their vertices coincide with each other. A magnetic layer of the mold is provided. Third,
A magnetic layer having a shape uniaxial magnetic anisotropy is provided by forming stripe-shaped irregularities parallel to the current direction of the coil on both surfaces of the spiral planar coil.

(1) FIG. 33 shows an outline of the planar inductor of the first structure. This planar inductor includes an insulator layer 20A, a first magnetic layer 30A, an insulator layer 20B, and a second magnetic layer 30B on both sides of the spiral planar coil 40.
It has a structure sandwiched in sequence. Here, the insulator layer 20
Is indicated by a dot (the same applies to FIG. 35). In the case of the configuration as shown in FIG. 33, in the first magnetic layer 30A closest to the spiral planar coil 40, the portion corresponding to the A region is likely to be saturated, but the magnetic flux leaking from the A region into the space is It passes through a portion corresponding to the B region of the second magnetic layer 30B. After all, the magnetic flux passes in the direction of the hard axis of magnetization in both the first and second magnetic layers, and magnetic saturation hardly occurs.

FIG. 34 shows an example of the DC superimposition characteristic of the planar inductor of FIG. 33 by a solid line and an example of the DC superimposition characteristic of the planar inductor of FIG. 29 by a broken line. As is clear from FIG. 34, in the case where the number of magnetic layers is two, the inductance is doubled and the DC current at which the inductance starts to decrease is also increased as compared with the case where the number of magnetic layers is one.

In FIG. 33, the case where the upper and lower magnetic layers of the spiral plane coil are two each has been described.
As shown in FIG. 35, the magnetic layers may be further multilayered by providing four magnetic layers each. Also in this case, the uniaxial magnetic anisotropy directions of the odd-numbered magnetic layers and the even-numbered magnetic layers of the spiral planar coil 40 are orthogonal to each other.

The planar inductor shown in FIG. 33 or 35 can be manufactured by the following method. 3μ as a magnetic material
When using a soft magnetic ribbon such as an amorphous alloy, a crystalline alloy, or an oxide having a thickness of m or more, uniaxial magnetic anisotropy is introduced in advance in each magnetic substance, and uniaxial magnetic anisotropy is provided for each layer. The layers are laminated with an insulating layer in between so that the directions of magnetic anisotropy are orthogonal to each other.

When a magnetic material is formed by a thin film process such as a vapor deposition method or a sputtering method, uniaxial magnetic anisotropy is introduced by film formation in a static magnetic field or heat treatment in a magnetic field after the film formation. In this case, the magnetic material preferably has a small magnetostriction, but if the stress distribution can be appropriately controlled, it is considered that uniaxial magnetic anisotropy can be introduced through the inverse magnetostriction effect even in a material having a relatively large magnetostriction. When manufacturing the planar inductor of FIG. 33 or FIG. 35 by the thin film process, it is advantageous in terms of productivity to use a multi-source film forming apparatus so that the magnetic layers and the insulating layers can be alternately formed. is there.

(2) FIG. 36 shows an outline of the planar inductor having the second structure. In this planar inductor, both surfaces of the spiral planar coil 40 are covered with an insulating layer 20 and a magnetic layer 30.
4 triangular magnetic bodies having a structure in which they are sequentially sandwiched, and each magnetic layer 30 has uniaxial magnetic anisotropy introduced in a direction parallel to the bottom side, and arranged so that their vertices coincide with each other. It is configured with. In the planar inductor of FIG. 36, since the direction of the magnetic field generated by the coil and the direction of the easy axis of magnetization are orthogonal to each other in the entire region of the magnetic layer 30, there is no region where magnetic saturation easily occurs.

FIG. 37 shows an example of the DC superimposition characteristic of the planar inductor of FIG. 36 by a solid line and an example of the DC superimposition characteristic of the planar inductor of FIG. 29 by a broken line. As is apparent from FIG. 37, although the inductance of the planar inductor of FIG. 29 is large in the small current region, it is sharply decreased by a slight increase in the DC superimposed current and then becomes constant. This region where the inductance is constant is because the magnetic material in the region B in FIG. 29 is operating. On the other hand, in the planar inductor of FIG. 36, the range of constant inductance is wide from the small current side to the large current side, and the inductance value itself is also shown in FIG.
It is about twice as large as the case.

The planar inductor shown in FIG. 36 can be manufactured by the following method. When using a soft magnetic ribbon having a thickness of 3 μm or more, such as an amorphous alloy, a crystalline alloy, or an oxide, the ribbon is cut into a triangular shape having one or more sides of the rectangular spiral coil as a base. After that, heat treatment is performed in a state where a magnetic field is applied in parallel to the bases of these to impart uniaxial magnetic anisotropy. Then, the four triangular magnetic ribbons are arranged such that the easy axis of magnetization is parallel to the coil conductor.

When the film is formed by a thin film process such as a vapor deposition method or a sputtering method, a triangular mask is used and uniaxial magnetic anisotropy is imparted by film formation in a static magnetic field. That is, a magnetic field is applied parallel to the direction in which the coil conductors in the A region extend while forming a triangular resist mask in the B region to form a magnetic film in the A region. After forming a magnetic film with a predetermined thickness in the region A, the resist in the region B is removed and the magnetic film thereon is lifted off. Next, a resist mask is formed in the area A, and a magnetic field is applied in parallel with the direction in which the coil conductor in the area B extends to form a magnetic film in the area B. Finally, in the same manner as above, the remaining resist is removed and the magnetic film thereon is lifted off.

(3) The outline of the planar inductor of the third structure is shown in FIG. In this planar inductor, both surfaces of the spiral planar coil 40 are covered with an insulating layer 20 and a magnetic layer 30.
In the magnetic layer 30, stripe-shaped irregularities are alternately formed in parallel with the direction of the current flowing through the planar coil 40 (see FIG. 39 for the detailed shape).
Unidirectional magnetic anisotropy can be provided by the stripe-shaped irregularities. In the planar inductor of FIG. 38 as well, in the entire region of the magnetic layer 30, the direction of the magnetic field generated by the coil and the direction of the easy axis of magnetization are orthogonal to each other, so there is no region where magnetic saturation easily occurs.

As described above, as a method for forming the magnetic material layer having stripe-shaped concavities and convexities, a method of forming the magnetic material layer after forming the stripe-shaped concavities and convexities on the base by photolithography or mechanical processing, and Alternatively, a method of forming stripe-shaped irregularities on the magnetic layer itself by photolithography or mechanical processing after the magnetic layer is formed.

When the surface of the magnetic layer is made anisotropic,
The shape magnetic anisotropy is induced by the following mechanism.
Generally, a ferromagnet is composed of multiple magnetic domains, but it is known that a sufficiently thin film does not have a domain wall extending from the upper surface to the lower surface of the magnetic film and a single domain structure is realized in the film thickness direction. ing. It can be considered that the magnetic moment in the magnetic domain has a uniform direction and size due to exchange interaction, which is a short-range force, and rotates rigidly with respect to the external field. Also, when magnetic poles appear due to unevenness on the surface of the thin film, a demagnetizing field and a stray magnetic field are generated. Therefore, when an anisotropic shape is formed on the surface or interface of the magnetic thin film to introduce shape magnetic anisotropy, the magnetic moment in the film is affected. However, the surface shape of the magnetic layer preferably satisfies certain conditions as described below.

As shown in FIG. 39, consider a magnetic thin film having strip-shaped irregularities parallel to each other on the surface or interface. Now, paying attention to the strip-shaped magnetic body portion of the convex portion, the existence region of the i-th magnetic body is expressed as in Expression (1). Here, d is the thickness of the magnetic material in the concave portion, L is the width of the convex portion, W is the step difference of the concave and convex portions, and δ is the interval between the convex portions.

[0102]

[Equation 1]

These expressions mean a surface structure in which strip-shaped irregularities extending infinitely in the Y direction are infinitely repeated in the X direction. When the original magnetic anisotropy of the film is sufficiently small, the magnetization vector I becomes parallel to the film surface due to the shape magnetic anisotropy of the entire film. Here, the direction cosine of I in the X-axis direction is set as cosφ. When cosφ is not 0, a magnetic pole having an areal density represented by the product of the magnetization I and cosφ occurs on the YZ plane of the strip-shaped magnetic body. The magnetic field generated by this magnetic pole can be analytically solved as a function of (x, z). Focusing on the magnetic body with i = 0, the demagnetizing field Hd exerted on itself and the effective magnetic field Hm received from the infinitely continuous strip-shaped magnetic body are represented by the formula (2).

[0104]

[Equation 2]

Considering the magnetostatic energy of Hd and Hm as a function of φ, and considering the stable state of the band-shaped convex magnetic body of i = 0, φ = 0 (I is parallel to the band direction) and φ = π. The energy difference density Uk per unit volume with / 2 (I is perpendicular to the band direction) is as shown in Expression (3) on average in the film thickness direction. However, the positive / negative of Uk is determined so that the band direction (Y axis) becomes the easy axis when Uk> 0.

[0106]

[Equation 3]

By forming irregularities on the surface of the magnetic material in this way, shape anisotropy can be introduced into the magnetic material. However, in order to stably set the band direction (Y axis) as the easy axis in the entire film, at least the central portion (X = 0, Z =
0) must be the easy axis. Therefore, by paying attention to (X = 0, Y = 0) in the Uk equation and considering up to i = ± 1, the Uk equation is expressed as the equation (4).

[0108]

[Equation 4]

Since the first term of this Uk is always positive, U
The sign of k is determined by the sign of the second term. Therefore, if the surface shape satisfies the inequality of the expression (5), it is effective to provide the easy axis in the direction in which the belt-shaped unevenness on the surface extends, that is, the difficult axis in the vertical direction.

[0110]

[Equation 5]

FIG. 40 shows changes in the second term of the Uk equation when W / L and δ / L are set to various values. Figure 4
As can be seen from 0, when the steps of the unevenness become shallow, as in the case of δ / L = 1/16, for example, the anisotropy is reversed in polarity, and the direction perpendicular to the direction in which the strip-shaped unevenness extends becomes the easy axis of magnetization. Could be. As an example, W = 0.5 μm, L
= 4 μm, δ = 2 μm, and d = 2 μm, the energy difference was calculated when taking into account even the most adjacent (i = ± 1) convex portion. there were. However, the value of magnetization was assumed to be 1T.

FIG. 41 shows an example of the DC superposition characteristics of the plane inductor (solid line) of FIG. 38 and the plane inductor (broken line) of FIG. From FIG. 41, it can be seen that in the planar inductor of FIG. 38, the constant inductance range is wide from the small current side to the large current side.

As described above, if the structures (1) to (3) are adopted, the operation of the magnetic layer is fixed to the axis of hard magnetization, so that magnetic saturation hardly occurs. In addition, since the hard axis of the magnetic body is used, the magnetization process becomes rotational magnetization, which makes it possible to reduce high-frequency eddy current loss as compared with domain wall motion magnetization, and is also effective in improving frequency characteristics.

The introduction of the uniaxial magnetic anisotropy has been described above by limiting the coil shape. Next, the magnetic element when the spiral coil shape is rectangular and the terminal is easily taken out will be described. .

Here, a plane inductor will be taken up as a plane magnetic element and specifically described. The planar transformer is structurally the same as the planar inductor except that the primary and secondary ones are stacked, and the effect obtained by the fourth means is similar. The BH curve observed in the easy magnetization axis direction and the hard magnetization axis direction of the magnetic substance having uniaxial magnetic anisotropy is omitted, but the magnetic permeability is very high in the easy magnetization axis as shown in FIG. , Easy to saturate, and hard to saturate in the opposite direction in the hard magnetization direction. Further, as shown in FIG. 42, the magnetic permeability of the easy axis is high at low frequencies, but sharply decreases at high frequencies. On the other hand, the magnetic permeability of the hard axis is inferior at low frequencies, but at high frequencies it is much higher than that of the easy axis. It is considered that if only the hard axis of the magnetic material can be used in the planar magnetic element, it will greatly contribute to the improvement of the electrical characteristics of the element.

This method of the fourth means is roughly divided into 3
There are two possible cases. Therefore, in this case, description will be sequentially made assuming that there are three cases.

First, a rectangular spiral coil is used, and the magnetic material is laminated on the upper and lower surfaces of the spiral coil via an insulator so that the long axis of the spiral coil coincides with the easy axis of magnetization of the magnetic material. Such a first of the fourth means is shown in FIG. 43A is a plan view in which the magnetic layer 30 is disposed on the upper and lower surfaces of the planar coil 40 sealed with the insulator 20, and FIG. 43B is the plan view of FIG.
FIG. 3B is a cross-sectional view taken along 3B (42 indicates a conductor and 100 indicates a magnetic flux). Here, the ratio of the long axis to the short axis of the rectangular spiral coil (aspect ratio = long axis length m / short axis length n) is set as large as possible. If the aspect ratio m / n is sufficiently large, in most regions of the magnetic material,
Although the magnetic field direction and the easy magnetic axis are orthogonal to each other, in order to make this state more complete, as shown in FIG. 44, a magnetic body is formed only on the coil conductor portion in the long axis direction of the rectangular spiral coil. good. However, the cross-sectional view of FIG.
It has the same shape as the cross-sectional view of A (also in FIG. 45).

The second will be described. Two rectangular spiral coils as described in the first paragraph are connected in series so that the two longitudinal axes of the rectangular spiral coils are aligned with each other.
Place on the same plane. Further, the magnetic body is arranged on the upper and lower surfaces of the coil with an insulator so that the long axis of the rectangular spiral and the easy axis of magnetization of the magnetic body coincide with each other.

FIG. 45 shows a case where two rectangular spiral coils are arranged in the longitudinal direction, and FIGS. 46A and 47A.
Shows the case where they are arranged in the short axis direction. Also, in FIG.
Is a cross-sectional view taken along the line 46B of FIG. 46A, and the same applies to FIG. 47B. Thus, by connecting the two rectangular spiral coils in series, it is possible to obtain an inductance value that is at least twice as high as that in the case of FIGS. 43 and 44. Further, regarding the connection between the two rectangular spiral coils, wiring that extends through the air is not necessary.

There are two possible coil connection methods for arranging two rectangular spirals in the minor axis direction. Figure 46
47 shows the case where the winding directions of the two rectangular spiral coils are opposite, and FIG. 47 shows the same case. The magnetic path through which the magnetic flux passes is subdivided in the latter as shown in the figure. Which one is superior depends on various conditions, and thus is selected appropriately.

Incidentally, in FIGS. 45, 46 and 47,
The magnetic layer 30 may be formed over the entire surface of the spiral coil as shown in FIG. 43A.

The third will be described. As shown in FIG. 44, FIG. 45, FIG. 46, and FIG. 47, since the winding start and winding end portions of the rectangular spiral coil are exposed, the terminal can be pulled out very easily.

As described above, according to the fourth means, since the hard axis of the magnetic material can be effectively utilized, the magnetization process depends on the rotation magnetization, and not only the effect of magnetic saturation is reduced. It is also effective for improving high frequency characteristics.

43, 44, 45, 46 and 4
In FIG. 7, the case where only one uniaxial anisotropic magnetic body is formed on the upper surface and the lower surface of the spiral coil is shown, but generally, these magnetic bodies are used in a multilayered form.

Various methods are conceivable for realizing the device proposed by the fourth means. When using a soft magnetic ribbon such as an amorphous alloy, a crystalline alloy, or an oxide having a thickness of 3 μm or more, uniaxial magnetic anisotropy is given in advance by heat treatment in a magnetic field, and a rectangular spiral film or the like is used. Stack with. At this time, a magnetic material having a small magnetostriction is selected in order to avoid the influence of the stress due to the lamination as much as possible.

When the film is formed by a thin film process such as a vapor deposition method or a sputtering method, uniaxial magnetic anisotropy is given by film formation in a static magnetic field or heat treatment in a magnetic field after the film formation. At this time as well, it is desired that the magnetic material has a small magnetostriction, but if the stress distribution can be controlled appropriately, it is possible to impart uniaxial magnetic anisotropy through the inverse magnetostriction effect even to a material having a relatively large magnetostriction value. It is believed that In order to realize the magnetic body structure by the fourth means in the thin film process, it is necessary to alternately form the magnetic bodies and the insulators. Therefore, it is advantageous in terms of productivity to use a multi-source film forming apparatus. .

Now, when the planar magnetic element by the fourth means is integrated with other elements such as a transistor, a resistor and a capacitor, in order to prevent malfunction of the circuit due to leakage magnetic flux, in particular, FIGS. 46 and 47, the magnetic shield magnetic body is formed in the portion where the coil conductor is exposed. An example of this is shown in FIGS. 48A and 48B. Here, FIG. 48A is a plan view and FIG. 48B is a cross-sectional view, and the numbers of the members are the same as those in FIG. 43.

The fifth means of the present invention will be described. 49 and 50 show a plane coil that constitutes a magnetic element according to the fifth means.

The plane coil of FIG. 49 has a plurality of one-turn plane coils 4 each having a substantially square outer shape and different outer dimensions.
0s are arranged on the same plane, and each one-turn planar coil 40 has two external connection terminals on one side of the square. Similar to FIG. 49, the plane coil of FIG. 50 has a substantially square outer shape and has a plurality of one-turn flat coils 40 having different outer dimensions arranged on the same plane.
The turn plane coil 40 has a total of four external connection terminals, two on each of two opposite sides of the square. Note that although FIGS. 49 and 50 show a one-turn flat coil whose outer shape is substantially square, the outer shape of the one-turn flat coil is not particularly limited.

Both sides of such a planar coil are sandwiched by the magnetic layers 30 shown by broken lines in FIGS. 49 and 50. As the magnetic material, soft ferrite, magnetic ribbon, magnetic thin film, or the like is used. However, when using a magnetic ribbon or a magnetic thin film other than ferrite, it is necessary to provide an insulating layer between the planar coil and the magnetic layer 30.

Since the planar magnetic element of the fifth means does not need to provide through-hole conductors or terminal lead-out conductors as in the case where a spiral coil is used as the planar coil, the manufacturing process is simplified. Also, each one
Since all the external connection terminals of the turn plane coil 40 are provided outside the magnetic layer 30, connection with an external circuit is extremely easy.

The inductance adjusting effect when the planar magnetic element according to the fifth means is used as an inductor will be described. As described below, the inductance is
It can be adjusted by changing the connection method between the external connection terminals or by selecting the external terminal, that is, the one-turn plane coil to be used.

FIG. 51 is a plan view of the planar magnetic device of FIG. 49.
Except for the outermost one and the central one, the adjacent ones are connected to each other. In FIG. 51, the directions of the currents flowing through the adjacent coil conductors are opposite to each other.
Therefore, the magnetic field generated is similar to the case of a zigzag coil pattern.

FIG. 52 is a plan view of the planar magnetic device of FIG. 49.
With the exception of the outermost one and the central one, those which are line-symmetrical to each other are connected to each other. In FIG. 52, the directions of the currents flowing through the adjacent coil conductors are opposite to each other. Therefore, the generated magnetic field is similar to that of the spiral coil pattern.

FIG. 53 shows the planar magnetic element of FIG. 49 in which the connection method of FIG. 51 and the connection method of FIG. 52 are used together. In FIG. 52, both the location where the directions of the currents flowing through the adjacent coil conductors are opposite to each other and the location where the directions are the same are included. Therefore, the generated magnetic field is similar to the case of the zigzag-spiral composite coil pattern.

In the connection method shown in FIGS. 51 to 53, the value of the inductance L is the largest in the case of FIG.
3, the order of FIG. 51 becomes smaller. As described above, in the planar magnetic element of the fifth means, the inductance can be adjusted by changing the connection method between the external connection terminals. The method of connecting the external connection terminals is not limited to the method shown in FIGS. 51 to 53, and can be appropriately selected by the user so as to obtain the required inductance.

FIG. 54 shows the inductance value obtained by one 1-turn flat coil when the two external connection terminals of the 1-turn flat coil having different outer shapes are connected to each other in the magnetic element of FIG. . As is apparent from FIG. 54, various inductance values can be obtained by selecting one-turn flat coils having different outer dimensions. Further, by selecting a one-turn flat coil as shown in FIG. 54 and changing the connection method shown in FIGS. 51 to 53 in combination, the inductance value can be trimmed in a wide range and finely.

Next, the case where the planar magnetic element according to the fifth means is used as a transformer will be described. When external connection terminals are provided as shown in FIG. 49, a plurality of plane coils are divided into two or more groups as shown in FIGS. 55 to 57, and one-turn plane coils in the same group are externally connected to each other. The transformer can be configured by. 55 and 56 show a 1-input-1 output type transformer, and FIG. 57 shows a 1-input-2 output type transformer. The method of connecting the planar coils in the same group divided into two or more groups is not limited to the method shown in FIGS. The inductance of each coil and the coupling coefficient between the coils can be adjusted by variously changing the external connection method of the plurality of planar coils forming the primary coil, the secondary coil, the tertiary coil, .... This means that the transformer transformation ratio and the current transformation ratio can be adjusted from the outside.
In FIG. 58, the planar magnetic element according to the fifth means has one input-1
The results of investigating the effect of adjusting the transformation ratio and the current transformation ratio by the external connection method when applied to the output type transformer are shown.

In the above, the adjustment effect of the electrical characteristics has been described by taking the connection method of the external connection terminals in the planar magnetic element of FIG. 49 as an example. If external connection terminals are provided as shown in FIG. 50, the variation of the terminal connection method is further expanded, and a finer adjustment effect can be obtained. However, if the number of external connection terminals is too large, the user may erroneously connect. Therefore, as shown in FIG. 49 or FIG. 50, the number of external connection terminals per planar coil is 2 to 4 Is considered sufficient.

If it is not necessary to adjust the electrical characteristics from the outside and a large inductance is required, the spacing between the coil conductors should be made as small as the manufacturing process allows, and the external terminals should be arranged as shown in FIG. Connecting. On the other hand, although the inductance may be small, in order to improve the frequency characteristics, the coil-to-coil spacing is made as large as possible and the external terminals are connected as shown in FIG. Similarly, even when applied to a transformer, if it is not necessary to adjust the electrical characteristics from the outside, the distance between the coil conductors should be as small as possible. By configuring the planar coil in this way, the fixed characteristic type planar magnetic element can be improved in performance.

Further, in order to miniaturize these planar magnetic elements, it is preferable to manufacture them by using a thin film process similar to the semiconductor manufacturing process. Si, GaAs
By forming the magnetic element of the fifth means on the semiconductor substrate such as, it is possible to make monolithic with active elements such as transistors and passive elements such as resistors and capacitors.
Can be miniaturized. When a magnetic element is formed on a semiconductor substrate, it may be on the same plane as the active element or may be on the upper or lower part of the active element.

FIG. 59 shows an active element 90 on the semiconductor substrate 10.
And the magnetic element 92 is formed on the same plane.
In FIG. 60, an active element 90 is formed in a semiconductor substrate 10, a wiring layer 95 is formed on the substrate 10 via an insulator layer 20,
The magnetic element 1 is formed on the wiring layer 95 via the insulator layer 20. In FIG. 61, the magnetic element 1 is formed on the semiconductor substrate 10, and the active element 90 is formed on the magnetic element 1 with the insulator layer 20 interposed therebetween. In any element, the semiconductor substrate 10, the active element 90, and the magnetic element 1 are connected by wiring through a contact hole (not shown). As in the case of the fifth means, the present invention makes it possible to form an element integrally with an inductor, a transformer, and the like, each of which includes an active element and a passive element formed on a semiconductor substrate and a flat coil, by any means. it can. This can be referred to for any means as well, and will be described here only.

Finally, the sixth means will be described. Figure 6
2A shows a sectional view of the magnetic element according to the sixth means. When considering the increase of the current capacity, as shown in FIG. 62A, the conductor 42 forming the coil is formed into a planar shape, and the planar conductor magnetizes the magnetic body 30 arranged via the insulator 20. Is mentioned. In this case, since the magnetizing current is a surface current, the effective cross-sectional area increases and the allowable current increases. Although the outer iron structure is shown in FIG. 17, the structure shown in FIG. 62A can realize a substantially complete inner iron structure, and this structure can also sufficiently reduce the leakage magnetic field. Although the inductance varies depending on the driving frequency, the structure shown in FIG. 17 is advantageous in the low frequency region and the structure shown in FIG. 18 is advantageous in the high frequency region beyond the frequency region of about 1 MHz. However, in terms of current capacity,
The structure shown in 2A is absolutely advantageous.

Consider the allowable current (Imax) in the one-turn structure coil shown in FIG. 62A. 62B shows symbols indicating the dimensions of each part, and the member numbers are the same as in FIG. 62A. The inductance L (H) is L = 2 μsδ2ln (d1 / d2) × 10 ^-7 , and the DC resistance RDC (Ω) is RDC = (ρ / πδ1) ln (d1 / d2). Note that μs is the relative permeability of the magnetic substance, and ρ is the specific resistance.

Al (Allowable current density 10 ⁸ (A
/ M ² )) is used, Imax = π × 10 ⁸ · d 1 · d 2 (A). If a flat inductor having the same shape as this is realized by a planar spiral coil, the cross-sectional area of the conductor is considerably reduced, and therefore, Imax of about 2 digits or less can be obtained as a rough order.
As shown in FIG. 63A, a plurality of structural coils are formed in a plane and connected in series, so that high inductance can be realized. Furthermore, as shown in FIG. 63B, similar structures may be stacked. In this case, the inductance per unit area becomes large.

Further, the transformer can be constructed with a one-turn type coil as shown in FIG. 62A. That is, as shown in FIG. 64, the conductor layer 40 surrounding the magnetic layer 30.
A and 40B may be multilayered with the insulator layer 20B interposed therebetween. In this case, the number of laminated conductor layers of the primary coil and the secondary coil may be determined according to the desired winding ratio.

Although each means has been described above individually, it is possible to improve various characteristics even if each means is used independently. However, by appropriately combining each means,
It is possible to improve the characteristics and improve the operability in handling.

Selection of the Materials Here, materials (conductor 42, magnetic body 30, substrate 10 and insulator 20) necessary for constructing a magnetic element for carrying out the present invention will be described.

First, as the material of the coil conductor 42, a low resistance metal is mainly considered. For example, Al and Al alloys, Cu and Cu alloys, Au and Au alloys, Ag and A
A typical example is a g-alloy, but it goes without saying that it is not limited to these. Further, since the flat coil using these metals can increase the rated current as the allowable current density is higher, it is preferable to use a material having high resistance to coil breakage due to electromigration, stress migration, thermal migration and the like.

The magnetic body 30 is also a plane inductor and a transformer.
Suitable for the frequency domain used and the required characteristics.
It can be selected as appropriate, high permeability material, constant permeability material,
Examples include high magnetic flux density materials and low loss materials. example
For example, permalloy, ferrite, sendust, various amorphous materials
A magnetic alloy or a single crystal film can be used.
Considering for electric power, high magnetic flux is used so that the magnetic flux is not easily saturated.
It is desirable to use a bundle density material. Also single magnetism
It does not have to be a body, for example FeCo film and SiO ₂With a membrane
Layered product, artificial lattice film, FeCo phase and B_FourMixing with phase C
A phase, a particle dispersion layer, etc. may be used. When forming on the conductor
If the magnetic substance is an insulator,
If it has a property, it is necessary to form an insulator between it and the conductor
There is.

Further, in order to avoid the influence of the saturation of the magnetic material, the magnetization direction of the planar coil and the hard axis of the magnetic material may be made to coincide with each other, and the anisotropic magnetic field of the magnetic material may be made larger than the magnetic field formed by the coil current. preferable. Specifically, a magnetic material having a high saturation magnetization and an anisotropic magnetic field Hk of an appropriate value is preferable. In addition, in order to avoid the influence of stress due to stacking etc. as much as possible, a magnetic material with a magnetostriction as small as possible (for example, λ
It is preferable to select s <10 ⁻⁶ ).

The selection criteria of the magnetic material in this case will be described with reference to FIG. FIG. 65 shows the relationship between the number of turns of the coil conductor and the maximum permissible current and the magnitude of the magnetic field within the magnetic material plane generated when the maximum permissible current is passed. An Al-Cu alloy is used as the coil conductor, the conductor thickness is 10 μm, the inter-conductor spacing is 3 μm, and the external dimensions of the coil are changed by changing the number of turns.
Corresponding to this, the outer dimensions of the magnetic body are changed. An insulator layer having a film thickness of 1 μm is formed between the conductor and the magnetic body. Allowable current density of coil conductor is 5 × 10 ⁸ (A / m ² )
It is constant.

In the example of FIG. 65, the magnitude of the magnetic field generated when an allowable current is passed through the coil is about 20 to 30 Oe. Set the maximum value of the coil current to be used as the allowable current value of 80
%, A maximum magnetic field of 16 to 24 Oe will be applied to the magnetic substance. Therefore, in this case, the anisotropy magnetic field Hk of the magnetic body to which the uniaxial magnetic anisotropy is introduced is 16 to
A size of 24 Oe is required.

Since the magnitude of the anisotropic magnetic field of the magnetic material depends on the structural parameters of the magnetic element, it is not limited to the value shown here. However, in order to avoid the influence of magnetic saturation, a value of 5 Oe or more is preferable.

The substrate 10 is also not particularly limited, but at least the surface may be an insulator so as to be insulated from the magnetic substance or conductor formed on the substrate. However, it is desirable to use a semiconductor substrate made of Si or the like in consideration of easiness of microfabrication and making into one chip. In this case, it is necessary to make it an insulator by a method such as forming an oxide film on the surface.

Examples of the material of the insulator layer 20 include inorganic substances such as SiO ₂ and Si ₃ N ₄ and organic substances such as polyimide, but those having a dielectric constant as low as possible are preferable in order to reduce capacitive coupling between layers. . Further, the film thickness of the insulating layer is determined so that the uniaxial magnetic anisotropy introduced into the magnetic layer is not disturbed by the magnetic coupling between the upper and lower magnetic layers. The appropriate thickness of the insulator layer varies depending on the magnetic material used, and therefore is appropriately selected.

Example 1 An example by the first means will be described. The magnetic element shown in FIG. 6 was manufactured by the following method, and its performance was confirmed.

The surface of the silicon substrate is thermally oxidized to a film thickness of 1
A SiO ₂ film of μm was formed. On this SiO ₂ film, a sendust film having a film thickness of 1 μm and a film thickness of 1 μm are formed by the RF sputtering method.
m SiO ₂ films were sequentially formed.

On this SiO ₂ film, an Al—C film having a film thickness of 10 μm to be a coil conductor was formed by a DC magnetron sputtering method.
A u alloy film was formed. The Al-Cu was formed an SiO ₂ film as an etching mask film thickness 1.5μm on the alloy film. After coating a positive photoresist on the SiO ₂ film, it was patterned into a spiral coil having a line width of 37 μm and a line interval of 3 μm by photoetching. The exposed SiO ₂ film was etched by reactive ion etching using CF ₄ gas to form a spiral coil-shaped SiO ₂ mask. Furthermore, Cl ₂ , BCl ₃
The exposed Al-Cu alloy film is etched by a low pressure magnetron reactive ion etching with a gas to form an Al film.
A spiral coil conductor made of a Cu alloy was formed. At this time, the etching selection ratio of the Al—Cu alloy with respect to the SiO _{2 of} the mask and the underlying SiO ₂ was 15, and vertical anisotropic etching could be realized. In this way, a spiral coil having an outer dimension of 2 mm, a winding number of 20, a coil conductor width of 37 μm, a conductor interval of 3 μm, and a conductor thickness of 10 μm was formed. The groove aspect ratio is 3.3 from the conductor spacing of 3 μm and the coil conductor thickness of 10 μm.

After removing the photoresist pattern and the SiO ₂ mask, a SiO ₂ film was deposited by the bias sputtering method, and the groove between the coil conductors was filled with the SiO ₂ film. The upper surface of the SiO ₂ film was flattened by the etch back method. A 1 μm sendust film was formed on the SiO ₂ film, and a protective film made of a Si ₃ N ₄ film was further formed to produce a planar inductor.

As a result of measuring this planar inductor with an impedance meter, at a frequency of 2 MHz, a resistance component R = 5.8Ω, an inductance L = 3.78 μH, Q =
8 was obtained.

This planar inductor was used as an output side choke coil of a step-down chopper type DC-DC converter operating at 2 MHz switching. This DC-DC converter has an input voltage of 10V, an output voltage of 5V, and an output power of 500mW. As a result, it was confirmed to operate normally, the efficiency at the rated load was 70%, the loss due to the planar inductor was 58 mW, and the other semiconductor elements were 156 mW.

In order to confirm the performance of the above planar inductor, the same process was used, the coil conductor width was 21 μm,
A plane inductor was formed by setting the inter-conductor spacing to be 20 μm and the conductor thickness to be 4 μm. In this case, the groove aspect ratio is 0.
It is 2.

As a result of measuring this planar inductor with an impedance meter, at a frequency of 2 MHz, a resistance component R = 10.3Ω, an inductance L = 3.7 μH, Q =
It was 4.5.

This plane inductor is connected to the same DC-
When incorporated in a DC converter, the loss due to the planar inductor is 103 mW, and the converter efficiency is 65
Fell to%.

Example 2 Using the same process as in Example 1, a thin film flat transformer was produced. The primary coil has an outer shape of 2 mm, a winding number of 20, a conductor width of 37 μm, a conductor interval of 3 μm, a conductor thickness of 10 μm,
The groove aspect ratio was 3.3. The secondary coil has an outer shape 2
mm, number of turns 40, conductor width 17 μm, conductor spacing 3 μm,
The conductor thickness was 10 μm and the groove aspect ratio was 3.3. The gap between the lower and upper magnetic bodies is 23 μm.

As a result of measuring this flat transformer with an impedance meter, the primary side inductance was 3.8 μm.
The secondary inductance was 14 μH, the mutual inductance was 6.8 μH, and the coupling coefficient k was estimated to be 0.93.

When a 500 kHz sine wave voltage having an effective value of 1 V was applied to the primary side of this plane transformer, a sine wave voltage having an effective value of 1.7 V was generated on the secondary side. When a pure resistance load of 200Ω was connected to this plane transformer, the voltage fluctuation rate with respect to the terminal voltage when there was no load was about 10%.

This plane transformer was used for evaluation in a forward type DC-DC converter operating at 2 MHz switching. This DC-DC converter has an input voltage of 3
V, output voltage 5 V, output power 100 mW.
As a result, the loss of the transformer at the rated load was 88 mW.

In order to confirm the performance of the flat transformer manufactured above, a thin film flat transformer was manufactured using the same process as above. The primary coil had an outer shape of 2 mm, a winding number of 20, a conductor width of 21 μm, a conductor spacing of 20 μm, a conductor thickness of 10 μm, and a groove aspect ratio of 0.5. The secondary coil has an outer shape of 2 mm, a winding number of 40, a conductor width of 10 μm, a conductor interval of 10 μm, a conductor thickness of 10 μm, and a groove aspect ratio of 1.0.
And The gap between the lower and upper magnetic bodies is 23 μm
Is.

When a 500 kHz sine wave voltage having an effective value of 1 V was applied to the primary side of this plane transformer, a sine wave voltage having an effective value of 1.3 V was generated on the secondary side. The cause of the low secondary side voltage is that the primary side coil resistance is high, so that the primary side voltage drop is large and the transformer gain is reduced.

In the same manner as above, this plane transformer has 200
When a pure resistance load of Ω was connected, the voltage fluctuation rate with respect to the terminal voltage when there was no load was about 18%.

This plane transformer is replaced with the same DC-D as above.
When evaluated using a C converter, the transformer loss at the rated load was 152 mW, the heat generation was considerably large, and a temperature rise of 50 ° C. was observed.

Embodiment 3 An embodiment of the second means will be described. This embodiment is an embodiment in which an insulator layer is formed between the substrate 10 and the conductor 42 in FIG.

After forming a SiO ₂ layer (thickness 1 μm) on a Si substrate, a 5 μm Al layer was formed by a sputtering method (specific resistance 2.8 × 10 ⁻⁶ Ωcm). Then, a spiral coil (inner diameter: 1 mm, outer diameter: 5 mm) having a width of 5 μm (conductor aspect ratio of 1), a pitch of 10 μm and a number of turns of 200 was formed by etching with a photoresist method. Coil resistance is 120Ω, inductance is 0.14
It was mH.

[0176] This is a step-down chopper type 0.1W class D
When incorporated into a C-DC converter (operating frequency of 300 kHz) and tested, it was confirmed that it was operating as an inductor.

For reference, a spiral coil having a width of 10 μm (a conductor aspect ratio of 1/2), a pitch of 15 μm and a number of turns of 130 and having the same outer shape (the same occupied area) was prepared, and the inductance was 0.05 mH. It was

Example 4 C was formed on the upper and lower surfaces of the coil with a SiO ₂ layer (1 μm thick) interposed therebetween.
A coil was formed in the same manner as in Example 3 except that an o-Si-B system amorphous alloy (2 μm thick) layer was formed.

The inductance was 2 mH.

Example 5 This example is an example in which a transformer having a two-layer structure is used as the coil of Example 4.

The coil of the first layer was the same as the coil of Example 4. The coil of the second layer has a conductor thickness of 5 μm and a width of 5 μm.
(Conductor aspect ratio 1), pitch 20 μm, number of turns 1
A spiral coil of 00 was used so that the spiral centers were almost the same.

When the operation of the transformer was confirmed, it was confirmed that the transformer operated at the boost ratio 2 which was the same as the turn number ratio.

Example 6 An example in which the method of manufacturing the same magnetic element as in Example 3 is changed will be described.

After forming a SiO ₂ layer (thickness: 4 μm) on a Si substrate, an Al single crystal layer having a thickness of 10 μm was formed by the MBE method (specific resistance 2.6 × 10 ⁻⁶ Ωcm). Then, by the photoresist method, a spiral coil (inner diameter 1 mm, outer diameter 5 mm) having a width of 5 μm (conductor aspect ratio 2), a pitch of 10 μm and a number of turns of 200 was formed by etching. Coil resistance is 50Ω, inductance is 0.14m
It was H.

As compared to the case of the third embodiment, the coil resistance is lowered, so that the allowable current is increased and the power can be increased.

Example 7 An example in which the manufacturing method of a magnetic element similar to that in Example 3 was changed will be described.

After a SiO ₂ layer (thickness 1 μm) was formed on a Si substrate by an oxidation treatment, a 5 μm Al—Si—Cu alloy layer was formed by a vapor deposition method. Next, after forming a SiO ₂ layer (thickness 1 μm) by the CVD method, a resist pattern is formed and Al is formed by a magnetron RIE apparatus.
Cut the alloy layer, width 2μm (conductor aspect ratio 2.5),
A square meandering coil (inner diameter 1 mm, outer diameter 4 mm) having a pitch of 3 μm and a number of turns of 500 was prepared.

Then, a plasma CVD method using monosilane (SiO ₄ ) and nitrous oxide (N ₂ O) as raw materials was performed.
A SiO ₂ layer was formed on the coil. The plasma CVD method using this raw material is an example in which the supply is rate-controlled, and the conductor interval of this embodiment is as narrow as 1 μm and the conductor aspect ratio is as large as 2.5. It could be hollowed out. The inductance is 1.6m
It was H.

In this way, the high-frequency characteristics are remarkably different between the case where the coil-forming conductors are hollow and the case where the conductors are filled with silicon because the capacitance generated between the lines is significantly different. In the case of this example, the inductance did not decrease until 10 MHz, but when silicon was filled between the lines, a drastic decrease in inductance was observed at about 800 kHz.

Embodiment 8 In the second means, an embodiment in which the coil conductors are made hollow by the method shown in FIG. 13 will be described.

After forming a SiO ₂ layer (thickness: 1 μm) on a Si substrate by thermal oxidation, 1 μm is formed by a sputtering method.
An mAl layer was formed. Then, the Si substrate is exposed to the outside air to oxidize the surface, and then the sputtering method
The step of forming the 1-layer was repeated to form a conductor layer of 5 μm in which an aluminum oxide layer of about 30 Å was formed between Al layers of 1 μm. Next, a silicon oxide layer was formed on the surface by a plasma CVD method, and then a square meander coil was formed by a dry etching method. The coil specifications are
The outer diameter is 5 mm, the number of repetitions is 1000, the line width is 2 μm, and the conductor line interval is 0.5 μm. Then, a silicon oxide layer was formed by the plasma CVD method, and the conductor line interval was sealed in as a cavity.

A step-up chopper type DC-DC converter circuit (step-up ratio 1.
5V / 3V, output current 0.2mA) was built in to form a one-chip type DC-DC converter. The size is
The thickness is 0.5 mm, the size is 10 mm × 5 mm, and the driving frequency of the switching element in the circuit is 5 MHz. As a result of the operation test, it was confirmed that it was fully functioning. At a driving frequency of 500 kHz, impedance was insufficient and sufficient operation could not be realized.

One-chip DC-DC obtained in this example
By using the converter, a pager (registered trademark) or the like, which has been difficult to be formed into a card, can be formed into a card. FIG. 66 shows a schematic view of a card type pager using the one-chip DC-DC converter. Antenna section 210, operating circuit section 220, sounding section 230 such as a piezoelectric buzzer, and the one-chip type DC
The DC converter 240 and the DC converter 240 are arranged on the card base 200, and are covered with a cover portion (not shown) to form a card-shaped pager as a whole.

Embodiment 9 An embodiment of the third means will be described. The magnetic element of FIG. 23 was produced and its performance was confirmed.

A copper coil having a thickness of 100 μm was adhered onto a polyimide film, and then a planar coil patterned in a spiral coil shape by wet chemical etching was coated with a Co-type amorphous alloy foil having a thickness of 5 μm through a polyimide film having a thickness of 7 μm. A sandwiched planar inductor was formed.
At this time, the outer dimension a0 of the spiral coil was 11 mm. Permeability of Co-based amorphous alloy foil is 4500
It is estimated that the value of α is about 1 mm from the gap between magnetic bodies of 114 μm, and the external magnetic system dimension w is 15 mm (a0 +
4α). When a DC current of 0.1 A was passed through the thus formed planar inductor and the leakage magnetic field in the vicinity of the inductor was measured with a high-sensitivity Gauss meter, the leakage magnetic field was below the detection limit.

In order to compare the leakage magnetic fields of the above planar inductors, in a planar inductor formed by the same method as above, 12 mm was adopted as the outer dimension w of the magnetic material (a0 + α), and 0. When the leakage magnetic field in the vicinity of the inductor was measured by applying a DC current of 1A,
A stray magnetic field of about 30 Gauss was detected.

Embodiment 10 An embodiment according to the third means will be shown. This is an example in which the fourth means is added to the magnetic element of Example 9 (see FIG. 29).

On a semiconductor substrate, (1) a 1 μm thick Co-based amorphous magnetic thin film was formed by the RF magnetron sputtering method, and (2) an 1 μm thick insulating film (SiO ₂ ) was formed by the RF sputtering method. (3) On top of that, Al- having a thickness of 10 μm is formed by a DC magnetron sputtering method.
After forming the Cu alloy film, the planar coil was formed by patterning into a spiral coil shape by magnetron-type reactive ion etching. (4) Further, an insulating film (SiO ₂ ) was embedded on the spiral plane coil by a bias sputtering method to be flattened. (5) A 1 μm thick Co-based amorphous magnetic thin film was formed thereon by the RF magnetron sputtering method to form a planar inductor.

At this time, the magnetic permeability of the Co-based amorphous magnetic thin film was roughly determined with a sample vibrating magnetometer.
It was 000. Further, the outer dimension a0 of the spiral plane coil is 4.5 mm, and the gap between magnetic bodies is 12 μm.
Therefore, α is estimated to be 77 μm, and 5 mm (a 0 + 6.5α) is adopted as the outer dimension w of the magnetic body. Similar to Example 1, the leakage magnetic flux was measured in the vicinity of the planar inductor, but it was below the detection limit.

A planar inductor was formed on a semiconductor substrate by the same method as above, but only the magnetic material dimension w was 4.6 mm.
It was changed to (a0 + 1.3α). When the leakage magnetic field in the vicinity of the planar inductor was measured with a high-sensitivity Gauss meter as in Example 9, a leakage magnetic flux of about 50 Gauss was detected.

Example 11 Using the same technique as in Example 9, a planar inductor having various outer dimensions of a magnetic material was formed, and the inductance value was measured with an LCR meter. The outer diameter of the magnetic material was 15 mm.
Planar inductors with about 1.
A triple inductance value of 90 μH was obtained. This effect of increasing the inductance was similarly recognized in the case of the planar inductor formed by the method of Example 10.

Example 12 A hybrid type step-down chopper IC was constructed by using the planar inductor manufactured in Example 9. The IC includes a switch element using a power MOS-FET, a rectifying diode, a low voltage control unit, and the like. This converter operates at 100 kHz switching and has an input voltage of 10
V, output voltage 5V, output power 2W, an inductance of 80 μH or more is required as an output control choke coil, and the planar inductor according to the ninth embodiment satisfies this value. When this converter IC is actually operated, the planar inductor operates normally as a choke coil, and there is little linking of the switching waveform of the FET.
At the rated output (5 V, 0.4 A), the output ripple voltage had a peak value of about 10 mV, which was at a level without problems.

A planar inductor manufactured to compare the performance of Example 9 was used as a hybrid DC-type of Example 12.
When incorporated into a DC converter IC, a large linking is seen in the switching waveform of the FET (probably due to the effect of the leakage magnetic field of the planar inductor).
The peak value of the output ripple voltage at the rated output (5 V, 0.4 A) was 0.1 V (because the inductance value does not satisfy 80 μH required as a choke coil and ripple suppression is insufficient).

Embodiment 13 An embodiment of the fourth means will be shown. The magnetic element shown in FIG. 33 was produced and its performance was confirmed.

A copper foil having a thickness of 100 μm was adhered on a polyimide film having a thickness of 30 μm, and then patterned by wet etching into a rectangular spiral shape having a conductor width of 100 μm, an interval between conductors of 100 μm, and a winding number of 20 to form a planar coil. . A polyimide film having a thickness of 10 μm was overlaid on the flat coil. Both surfaces of these were sandwiched by Co-based amorphous magnetic ribbons (first layer) having a thickness of 15 μm and introduced with uniaxial magnetic anisotropy. This Co-based amorphous magnetic ribbon is produced by a molten metal quenching method using a single roll method, and uniaxial magnetic anisotropy is introduced by an annealing method in a magnetic field. About this magnetic ribbon, anisotropic magnetic field 2 Oe, hard axis permeability 5000, saturation magnetic flux density 10 k
G. A polyimide film having a thickness of 5 μm on both sides thereof and a C film having a thickness of 15 μm into which uniaxial magnetic anisotropy is introduced
A planar inductor was produced by sandwiching it between the o-type amorphous magnetic ribbons (second layer). The first and second Co-based amorphous magnetic ribbons are laminated so that the directions of uniaxial magnetic anisotropy are orthogonal to each other. The external dimensions of this planar inductor are 10 mm.

The direct current superposition characteristics of the inductance of the obtained planar inductor were measured. As a result, the inductance value was kept flat at 12.5 μH up to 400 mA, and started to decrease at 500 mA or more.

This planar inductor was used as an output side choke coil of a step-down chopper type DC-DC converter with an input voltage of 12V and an output voltage of 5V. This converter has a switching frequency of 500 kHz and a load current of 40 kHz.
It was possible to output up to 0 mA, and maximum output power of 2 W and efficiency of 80% were obtained.

The Co-based amorphous magnetic ribbon after quenching (Reference Example 13a) was used as it was, or the Co-based amorphous magnetic ribbon was subjected to non-magnetic field annealing (Reference Example 1).
A planar inductor was manufactured by the same method as above except that 3b) was used. The former had a magnetic permeability of 2000 and the latter had a magnetic permeability of 10,000, and no clear magnetic anisotropy was observed in either case.

The DC superposition characteristics of these planar inductors were measured. As a result, in the planar inductor using the high magnetic permeability magnetic ribbon of Reference Example 13b, the inductance was higher than the above, but the range of the direct current with constant inductance was up to 200 mA, and the direct current was 250 mA or more. The inductance dropped sharply. On the other hand, Reference Example 1
In the planar inductor using the low permeability magnetic ribbon of 3a,
The inductance was low compared to the above, and the inductance gradually decreased from the range where the direct current was small. The frequency characteristics of these two planar inductors were inferior to the above. In particular, the loss abruptly increased on the high frequency side of 100 kHz or more, and the Q value at 1 MHz fell to 1/2 or less of that in the case of Example 9.

These planar inductors were used as the output side choke coils of the same DC-DC converter as above. However, since the DC superposition characteristics were inferior to the above, the maximum load current was limited to about 200 mA. It was Therefore, the maximum output power is halved compared to the above and the efficiency is 70%.
It was about%.

Example 14 The spiral plane coil having 20 turns in Example 13 was used as the primary side, and the secondary side spiral plane coil having 10 turns was formed on the primary side spiral plane coil with an insulating layer interposed therebetween. Produced a planar transformer in the same manner as in Example 13. The DC superimposition characteristic of the primary-side inductance was almost the same as that of the planar inductor of Example 13.

This planar transformer was applied to a transformer of a forward type DC-DC converter having an input voltage of 12V and an output voltage of 5V, and the planar inductor of Example 13 was used for the output side choke coil. This converter has a switching frequency of 500 kHz and the DC-D applied in Example 13.
The rated output equivalent to that of the C converter could be obtained. As a result, miniaturization of the insulation type DC-DC converter was realized.

Reference example 13a or reference example 13 as a magnetic material
A flat transformer having the same structure as the above except that the magnetic substance b was used was produced. The DC superimposition characteristics of the primary side inductance were almost the same as those of the planar inductors of Reference Examples 13a and 13b.

This planar transformer was applied to the same forward type DC-DC converter transformer as described above. However, due to the magnetic saturation of the transformer, normal power conversion was not performed and the operation as a converter could not be confirmed.

Example 15 An example of producing the magnetic element of FIG. 35 by the fourth means will be described.

The surface of the silicon substrate is thermally oxidized to a film thickness of 1 μm.
m SiO ₂ film was formed. Next, using a RF magnetron sputtering device, a CoZrNb amorphous magnetic thin film with a film thickness of 1 μm was formed on the SiO ₂ film in a magnetic field of 100 Oe, and uniaxial magnetic anisotropy having an anisotropic magnetic field of about 5 Oe was introduced. did. On this magnetic thin film, a SiO ₂ film having a film thickness of 500 nm was deposited by the plasma CVD method or the RF sputtering method. Similarly, the formation of the magnetic thin film and the formation of the SiO ₂ film were repeated to form a total of 4 cycles of the multilayer film of the magnetic layer / insulating layer. The thickness of the uppermost SiO ₂ film was 1 μm. At this time, the direction of the magnetic field was changed during the film formation so that the uniaxial magnetic anisotropy directions of the adjacent magnetic layers were orthogonal to each other.

Next, using a DC magnetron sputtering device or a high vacuum vapor deposition device, a film thickness of 10 μm was formed on the SiO ₂ film.
Of Al-0.5% Cu layer was formed. This Al-0.5
A 1.5 μm thick SiO ₂ film was deposited on the% Cu layer. A positive type photoresist was spin-coated on this SiO ₂ film and patterned into a spiral coil by photolithography. Using the resist coil pattern as a mask, the SiO ₂ film is etched by reactive ion etching using CF ₄ gas, and the Al-0.5% Cu layer is further etched by reactive ion etching using Cl ₂ gas and BCl ₃ gas. Was etched to form a spiral flat coil having a conductor width of 100 μm, a conductor spacing of 5 μm, and a winding number of 20. To fill the groove between the coil conductors, a polyamic acid solution, which is a precursor of polyimide, was spin-coated to a thickness of 15 μm and thermally cured at 350 ° C. to form a polyimide. The surface of the polyimide film was etched back from the upper surface of the coil conductor to a thickness of 1 μm by reactive ion etching using CF ₄ gas and O ₂ gas.

As a comparative example, the magnetic thin film formation and the SiO ₂ film formation were repeated in the same manner as described above to form a multilayer film of the magnetic layer / insulator layer for a total of 4 cycles. Also in this case, the direction of the magnetic field was changed during the film formation so that the uniaxial magnetic anisotropy directions of the adjacent magnetic layers were orthogonal to each other.

During these steps, the lower magnetic layer undergoes temperature rising and lowering processes, but the heat resistance of the magnetic layer is good, and the magnetic characteristics are almost unchanged immediately after the magnetic film formation and after the element formation. The effect of heat on the magnetic properties was extremely slight.

When the electrical characteristics of the obtained thin film inductor were evaluated, the inductance L was 2 μH and the quality factor Q was 15 (5 MHz). Further, when the direct current superposition characteristics were measured, the inductance was flat up to a direct current superposition current of 150 mA, and decreased at 200 mA or more.

This thin film type inductor is used for input voltage 12
It was used as an output side choke coil of a step-down chopper type DC-DC converter with V and an output voltage of 5V. This converter has a switching frequency of 4MHz and a load current of 150m.
It can output up to A, and the maximum output power is 0.75W,
An efficiency of 70% was obtained.

It should be noted that substantially the same electrical characteristics can be obtained by using a SiO ₂ film formed by a CVD method or a bias sputtering method instead of using the above-mentioned polyimide as the insulator layer for filling the groove portion of the coil conductor. It was

A thin film inductor was manufactured by the same method as described above except that the CoZrNb amorphous magnetic thin film was formed in the absence of a magnetic field. The magnetic permeability of the magnetic film was 10,000, and no clear magnetic anisotropy was observed.

Although the inductance value of this thin film inductor was about 5 times as large as that of the above inductor, the range of direct current with constant inductance was extremely narrow at about 10 mA, and the direct current of 20 mA or more was used. When was superposed, the inductance value dropped sharply.

This thin-film inductor is set to the same DC as above.
-It was applied to the output side choke coil of a DC converter, but the maximum load current was limited to about 10 mA because the DC superposition characteristics were inferior to the above. Therefore, the maximum output power was reduced to 1/10 or less of the above.

Example 16 The spiral plane coil having 20 turns in Example 15 was used as the primary side, and the secondary side spiral plane coil having 10 turns was formed on the primary side spiral plane coil through a polyimide layer having a film thickness of 2 μm. A planar transformer was produced in the same manner as in Example 15 except that the flat transformer was formed. The DC superimposition characteristic of the primary-side inductance was almost the same as that of the planar inductor of Example 15.

This planar transformer was applied to a transformer of a flyback type DC-DC converter having an input voltage of 12 V and an output voltage of 5 V, and the thin film inductor of Example 15 was used as an output side choke coil. This converter is the first embodiment.
It was possible to obtain a rated output equivalent to that of the DC-DC converter applied in No. 5. By making all the magnetic parts thin, the size and weight of the isolated DC-DC converter can be greatly reduced.

As in the comparative example of Example 15, C was applied in the absence of a magnetic field.
A thin-film transformer was produced in the same manner as in Example 16 except that the oZrNb amorphous magnetic thin film was formed. 1
The DC superimposition characteristic of the secondary inductance was almost the same as that of the thin film transformer of the comparative example of Example 15.

This thin film type transformer is used in the same DC-type as above.
It was applied to a transformer of a DC converter, but due to saturation of the transformer, an excessive peak current flowed in the switching power MOSFET, and the element was destroyed.

Example 17 An example in which the magnetic element of FIG. 36 was manufactured by the fourth means will be described.

After a 100 μm-thick copper foil was bonded onto a 30 μm-thick polyimide film, the conductor width was 100 μm, the conductor interval was 100 μm, and the winding number was 2 by wet etching.
A plane coil was formed by patterning into a square spiral shape of 0. A 10 μm thick polyimide film was laminated on the flat coil.

Next, four thin ribbons were prepared by cutting a 15 μm thick Co-based amorphous magnetic alloy ribbon produced by the melt quenching method using the single roll method into an isosceles triangle having a base of 12 mm and a height of 6 mm. did. These four triangular amorphous ribbons were heat-treated in a magnetic field of 200 Oe parallel to the base of the triangle to give uniaxial magnetic anisotropy having an easy axis of magnetization parallel to the base. These amorphous ribbons had an anisotropic magnetic field of 2 Oe, a hard axis coercive force of 0.01 Oe, a hard axis permeability of 5000, and a saturation magnetic flux density of 10 kG.
Square type with two triangular amorphous ribbons arranged on both sides of a planar coil via polyimide film so that the easy axis of magnetization is parallel to the coil conductor of the spiral coil, with their vertices aligned It was sandwiched by the magnetic layers of to form a planar inductor. The external dimensions of this planar inductor are 12 mm.

When the direct current superposition characteristic of the inductance of this planar inductor was measured, the inductance value was kept flat at 12.5 μH up to a direct current of 200 mA and began to drop at 250 mA or more.

This planar inductor was applied to the output side choke coil of a step-down chopper type DC-DC converter with an input voltage of 12V and an output voltage of 5V. This converter
Switching frequency 500kHz, load current 200m
Can output up to A, maximum output power 1W, efficiency 8
0% was obtained.

The Co type amorphous magnetic ribbon after quenching (Reference Example 17a) was used as it was, or the Co type amorphous magnetic ribbon was subjected to non-magnetic field annealing (Reference Example 1).
A planar inductor was manufactured by the same method as above except that 7b) was used. The former had a magnetic permeability of 2000 and the latter had a magnetic permeability of 10,000, and no clear magnetic anisotropy was observed in either case. The DC superposition characteristics of these planar inductors were measured. As a result, in the planar inductor using the high-permeability magnetic ribbon of Reference Example 17b, the inductance was higher than the above, but the range of the direct current with constant inductance was up to 100 mA, and the direct current was 120 mA or more. The inductance dropped sharply. On the other hand, in the planar inductor using the low-permeability magnetic ribbon of Reference Example 17a, the inductance was lower than that described above, and the inductance gradually decreased from the range where the direct current was small. The frequency characteristics of these two planar inductors were inferior to the above. In particular, the loss abruptly increased on the high frequency side of 100 kHz or more, and the Q value at 1 MHz fell to 1/2 or less of that in the case of Example 13.

Although these planar inductors were used as the output side choke coils of the same DC-DC converter as described above, the DC load characteristics were inferior to the above, so the maximum load current was limited to about 100 mA. It was Therefore, the maximum output power is halved compared to the above and the efficiency is 70%.
It was about%.

Example 18 Except that the spiral plane coil with 20 turns in Example 13 was used as the primary side, and the secondary side spiral plane coil with 10 turns was formed on this primary side spiral plane coil via an insulator layer. Produced a planar transformer in the same manner as in Example 17. The DC superimposition characteristic of the primary side inductance was almost the same as that of the planar inductor of Example 5.

This planar transformer was applied to a transformer of a forward type DC-DC converter having an input voltage of 12V and an output voltage of 5V, and the planar inductor of Example 5 was used for the output side choke coil. This converter has a switching frequency of 500 kHz and is DC-DC applied in Example 17.
We were able to obtain the same rated output as the converter. As a result, miniaturization of the insulation type DC-DC converter was realized.

Reference Example 17a or Reference Example 17 as a magnetic material
A planar transformer having exactly the same structure as in Example 17 except that the magnetic substance b was used was produced. The DC superimposition characteristic of the primary-side inductance was almost the same as that of the planar inductor of Example 17. (Example 18 ') This planar transformer was applied to the same transformer of the forward DC-DC converter as in Example 18. However, due to the magnetic saturation of the transformer, normal power conversion was not performed and the operation as a converter could not be confirmed.

Example 19 An example in which the magnetic element of FIG. 36 was produced by the fourth means will be described.

The surface of the silicon substrate is thermally oxidized to a film thickness of 1 μm.
m SiO ₂ film was formed. After spin coating a negative type photoresist on this SiO ₂ film, the bottom side is 5 mm and the height is 2.5 m by photolithography.
Si of a pattern in which the vertices of two isosceles triangles of m are in contact
A resist pattern was formed so that the O ₂ film was exposed.
Exposed SiO using RF magnetron sputtering equipment
₂ Film thickness 1μm in 100Oe magnetic field parallel to the bottom of film
CoZrNb amorphous magnetic thin film of
Uniaxial magnetic anisotropy having an anisotropic magnetic field of Oe was introduced.
The resist pattern was removed with a solvent, and the magnetic thin film on the resist was lifted off.

The photoresist was spin-coated again, and by photolithography, a SiO ₂ film having a pattern in which the vertices of two isosceles triangles having a base of 5 mm and a height of 2.5 mm orthogonal to the formed magnetic thin film pattern were in contact with each other was formed. A resist pattern was formed so as to be exposed. At this time, the formed magnetic thin film pattern is covered with the resist pattern. Uniaxial magnetic anisotropy having an anisotropic magnetic field of about 5 Oe by forming a CoZrNb amorphous magnetic thin film with a thickness of 1 μm in a magnetic field of 100 Oe parallel to the bottom of the exposed SiO ₂ film using an RF magnetron sputtering device. Introduced sex. The resist pattern was removed with a solvent, and the magnetic thin film on the resist was lifted off.

The magnetic thin film thus formed has 5
It has a square pattern of mm square, and the easy axis of magnetization is parallel to each side.

On this magnetic thin film, plasma CVD or
SiO with a thickness of 1 μm by RF sputtering₂Deposited film
And use DC magnetron sputtering or high vacuum deposition equipment
To form an Al-0.5% Cu layer having a film thickness of 10 μm,
With a film thickness of 1.5 μm₂A film was formed. This SiO₂
Spin a positive type photoresist on the film.
And a photolithography
It was patterned in the shape of an il. At this time, a square spiral
Each side of the coil was aligned with each side of the lower magnetic thin film.
With a rectangular spiral coil resist pattern as a mask
Then CF_FourBy reactive ion etching using gas
SiO₂The film is patterned, and further SiO₂Membrane pattern
Cl as a mask₂And BCl₃Reactivity using gas
Pattern the Al-0.5% Cu layer by on-etching.
Conductor width 100 μm, conductor spacing 5 μm, number of turns
Twenty spiral plane coils were formed. Between coil conductors
In order to fill the groove part of the
Spin coating of a solution of realic acid to a thickness of 15 μm,
It was thermoset at 350 ° C. to form a polyimide. CF _FourGas and
And O₂Carp by reactive ion etching using gas
Polyimide film until the thickness of 1 μm from the top surface of the conductor
The surface was etched back.

Then, CoZr having uniaxial magnetic anisotropy introduced also in the upper portion is formed by the same method as the formation of the lower magnetic layer described above.
A thin film type inductor was manufactured by forming an Nb amorphous magnetic thin film. During these steps, the lower magnetic layer undergoes temperature rising and lowering processes, but the heat resistance of the magnetic material is good, and the magnetic characteristics are almost unchanged immediately after the magnetic film formation and after the element formation. The effect of heat on the was very slight.

When the electrical characteristics of this thin film type inductor were evaluated, the inductance L = 2 μH and the quality factor Q =
It was 15 (5 MHz). Further, when the DC superposition characteristics were measured, the inductance was flat up to a DC current of 80 mA and decreased at 100 mA or more.

Incidentally, instead of using the above-mentioned polyimide as the insulator for filling the groove portion of the coil conductor,
Even if a SiO ₂ film formed by the CVD method or the bias sputtering method was used, almost the same electrical characteristics were obtained.

An input voltage of 12 is applied to this thin film type inductor.
It was used as an output side choke coil of a step-down chopper type DC-DC converter with V and an output voltage of 5V. This converter has a switching frequency of 4MHz and a load current of 80m.
The maximum output power was 0.4 W and the efficiency was 70%.

A thin film inductor was manufactured in the same manner as in Example 15 except that the CoZrNb amorphous magnetic thin film was formed in the absence of a magnetic field. The magnetic permeability of the magnetic film is 10,000
And no clear magnetic anisotropy was observed.

The thin-film inductor had an inductance value about 5 times as large as that of the above inductors, but the range of direct current with constant inductance was extremely narrow at about 8 mA, and the direct current of 10 mA or more. When was superposed, the inductance value dropped sharply.

This thin-film type inductor has the same DC as the above.
-It was applied to the output side choke coil of the DC converter, but the maximum load current was limited to about 8 mA because the DC superposition characteristics were inferior to the above. Therefore, the maximum output power was reduced to 1/10 or less of the above.

Example 20 The spiral plane coil having 20 turns in Example 19 was used as a primary side, and a secondary side spiral plane coil having 10 turns was formed on the primary side spiral plane coil via a polyimide layer having a film thickness of 2 μm. A thin-film flat transformer was produced by the same method as in Example 19 except that the thin-film flat transformer was formed. The DC superimposition characteristic of the primary-side inductance was almost the same as that of the planar inductor of Example 19.

This plane transformer was applied to a transformer of a flyback type DC-DC converter having an input voltage of 12 V and an output voltage of 5 V, and the thin film inductor of Example 19 was used as an output side choke coil. This converter is the first embodiment.
It was possible to obtain a rated output equivalent to that of the DC-DC converter applied in No. 9. By making all the magnetic parts thin, the size and weight of the isolated DC-DC converter can be greatly reduced.

As in the comparative example of Example 19, C was applied in the absence of a magnetic field.
A thin film type transformer was produced in the same manner as described above except that an oZrNb amorphous magnetic thin film was formed. The DC superimposition characteristic of the primary side inductance was almost the same as that of the thin film transformer of Example 19.

This thin film type transformer is used in the same DC-type as above.
It was applied to a transformer of a DC converter, but due to saturation of the transformer, an excessive peak current flowed in the switching power MOSFET, and the element was destroyed.

Example 21 FIG. 38 shows an example in which a magnetic element was manufactured by the fourth means.

The surface of the Si substrate was thermally oxidized to form a SiO ₂ film having a film thickness of 1 μm. A positive type photoresist was spin-coated on the SiO ₂ film and patterned into a concentric coil shape by photolithography. Using this resist pattern as a mask, reactive ion etching using CF ₄ gas was performed to form a SiO ₂ film pattern having a convex portion width δ = 2 μm, a concave portion width L = 4 μm, and a step W = 0.5 μm. After removing the resist, a Co film having a thickness of 2 μm was formed by an RF magnetron sputtering device.
A ZrNb amorphous magnetic thin film was formed. Note that anisotropy other than shape anisotropy was prevented from being introduced by rotating the substrate without applying a magnetic field during film formation. Under the same sputtering conditions, smooth thermal oxidation SiO
_{When a} CoZrNb amorphous magnetic thin film was deposited on ₂ , magnetic anisotropy was scarcely observed near the center of rotation. Also when manufacturing this element, a magnetic thin film is formed near the center of rotation. This magnetic thin film is used as a lower magnetic layer having irregularities on one side.

On a CoZrNb amorphous magnetic thin film,
Film thickness of 500 by plasma CVD method or RF sputtering method
nm SiO ₂ film is deposited, and a DC magnetron sputtering device or a high vacuum vapor deposition device is used to form an Al-film having a thickness of 10 μm.
A 0.5% Cu layer is formed, and a SiO 2 film with a thickness of 1.5 μm
_Two films were formed. A positive type photoresist was spin-coated on the SiO ₂ film and patterned into a spiral coil by photolithography. Using this resist pattern as a mask, the SiO ₂ film is etched by reactive ion etching using CF ₄ gas,
Further, using the SiO ₂ film pattern as a mask, Cl ₂ gas and B
Al by reactive ion etching using Cl ₃ gas
-0.5% Cu layer is etched to make conductor width 100μ
m, spacing between conductors was 5 μm, and a spiral flat coil having 20 turns was formed. To fill the groove between the coil conductors,
15μ of polyamic acid solution which is a precursor of polyimide
m was spin-coated and heat-cured at 350 ° C. to form a polyimide. The surface of the polyimide film was etched back from the upper surface of the coil conductor to a thickness of 1 μm by reactive ion etching using CF ₄ gas and O ₂ gas.

On the polyimide film, a CoZrNb film having a thickness of 2.5 μm was formed by an RF magnetron sputtering device.
An amorphous magnetic thin film was formed. A positive type photoresist was spin-coated on the CoZrNb amorphous magnetic thin film and patterned into a concentric coil shape by photolithography. Using this resist pattern as a mask, the CoZrNb amorphous magnetic thin film was patterned by reactive ion etching using Cl ₂ gas and BCl ₃ gas, the convex width δ = 2 μm, the concave width L = 4 μm, and the unevenness W = 0. A 5 μm pattern was formed. This magnetic thin film is used as the upper magnetic layer.

During these steps, the lower magnetic layer undergoes temperature rising and lowering processes, but the heat resistance of the magnetic layer is good, and the magnetic characteristics are almost unchanged immediately after the magnetic film formation and after the element formation. The effect of heat on the magnetic properties was extremely slight.

The band-shaped irregularities provided on the surface or interface of the upper and lower CoZrNb amorphous magnetic thin films formed as described above satisfy the inequality of [Equation 5] described above.

When the electrical characteristics of this thin film type inductor were evaluated, the inductance L was 0.8 μH and the quality factor Q was 7 (5 MHz). Moreover, when the DC superposition characteristics were measured, the inductance was flat up to a DC current of 300 mA and decreased at 350 mA or more.

The SiO ₂ film underlying the lower magnetic layer and the upper magnetic layer may be patterned not only by photolithography but also by mechanical processing by fine cutting. Although the unevenness is formed only on one surface of the magnetic layer in this embodiment, the unevenness may be formed on both surfaces.

When an insulative magnetic material such as soft ferrite is used as the magnetic material layer, the magnetic material layer can be directly laminated on the plane coil. It can also be used as a base for giving unevenness to the layer.

Further, instead of using the above-mentioned polyimide as an insulator for filling the groove portion of the coil conductor,
Even if a SiO ₂ film formed by the CVD method or the bias sputtering method was used, almost the same electrical characteristics were obtained.

A thin film inductor was manufactured by the same method as in Example 21 except that the upper and lower magnetic layers were used without patterning the lower SiO ₂ film and the upper CoZrNb layer (implementation). Example 21a).

The lower SiO ₂ film is patterned to have a convex portion width δ = 2 μm, a concave portion width L = 20 μm, and an uneven step W = 1 μm, and the upper CoZrNb layer is patterned to have a convex portion width L = 20 μm and a concave portion width δ = 2 μm. A thin-film inductor was produced in the same manner as in Example 21, except that the unevenness W was patterned to W = 1 μm (Example 21b). In this case, the strip-shaped irregularities of the magnetic layer do not satisfy the above-mentioned inequality of [Equation 5].

When the characteristics of the thin film inductors of Examples 21a and 21b were evaluated, the inductance value was about eight times as large as that of the thin film inductor of Example 21, but a direct current of 20 mA or more was used. The inductance value dropped sharply when the current was superposed.

Example 22 An example in which the magnetic element of FIG. 43 was produced by the fourth means will be described.

After a copper foil having a thickness of 100 μm was adhered on a polyimide film having a thickness of 30 μm, it was patterned by wet etching into a rectangular spiral shape having a conductor width of 100 μm and a conductor interval of 100 μm to form a plane coil. Further, the hard axis permeability is 5000 and the saturation magnetic flux density is 10
A planar inductor was formed by using two layers of 15 μm uniaxially anisotropic Co-based amorphous magnetic foil having a kG and sandwiching a planar coil from above and below via a 10 μm polyimide film. The Co-based amorphous magnetic foil used here was produced by a melt quenching method using a single roll, and was given uniaxial magnetic anisotropy by a magnetic field annealing method, and an anisotropic magnetic field was 20e. there were. The first and second layers of the uniaxially anisotropic amorphous alloy foil of the present planar inductor are laminated by using a 5 μm thick polyimide film for interlayer insulation. The external dimensions of this inductor are 5 x 20 m.
m, the number of spiral turns of the plane coil is 20.

When manufactured in this way, the inductance value (12.5 μH) was flat up to a DC current of 400 mA and began to drop at 500 mA or more.

Example 23 A flat transformer was manufactured in the same manner as in Example 22. The number of turns of the primary side spiral coil is 20, and the number of turns of the secondary side spiral coil is 10. This plane transformer
The structure is exactly the same except for the planar inductor and the secondary spiral coil of the twenty-second embodiment. The DC superimposition characteristic of the primary-side inductance was almost the same as that of the planar inductor of Example 22.

Example 24 An example in which the magnetic element shown in FIG. 35B was produced by the fourth means will be described.

A CoZrNb amorphous magnetic thin film having a thickness of 1 μm was formed on a surface-oxidized silicon substrate (the thickness of the thermally oxidized SiO ₂ film was 1 μm) by an RF magnetron sputtering apparatus in a magnetic field of 1000 e to obtain a difference of about 50 e. Uniaxial magnetic anisotropy with an anisotropic magnetic field was imparted. in addition,
Thickness of 5 by plasma CVD or RF sputtering
Using these methods in which a 000 Å SiO ₂ film is deposited, a 5000 Å SiO ₂ film is used for interlayer insulation so that the easy axis of the CoZrNb magnetic film matches each layer, and a total of 4 periods of magnetic material layers are used. / After forming the multilayer film of the insulator layer,
An Al-0.5% Cu layer having a thickness of 10 μm was formed using DC magnetron sputtering or a high vacuum vapor deposition apparatus. On the Al-0.5% Cu film, a Si film having a thickness of 1.5 μm is formed.
O ₂ was formed, a positive type photoresist was spin-coated, and the long axis of the rectangular spiral coil was patterned by photolithography so that it coincided with the easy axis of the magnetic material. The coil pattern of the resist as a mask to pattern the SiO ₂ by reactive ion etching using CF ₄ gas, further SiO ₂
Al-0.5% by reactive ion etching using Cl ₂ and BCl ₂ gas using the coil pattern of
Cu was coil patterned. The coil pattern is
The width is 100 μm, the conductor interval is 5 μm, and two rectangular spiral coils are arranged in the short axis direction and connected in series, and the number of spiral turns is 20. 1 after Al-0.5% Cu etching
In order to flatten the 0 μm step, a polyimide precursor polyamic acid solution was spin-coated to a thickness of 15 μm and thermally cured at a temperature of 350 ° C. for polyimidization. Further, the surface of the polyimide film was etched back by reactive ion etching using CF ₄ gas and O ₂ gas until the thickness became 1 μm from the upper surface of the Al-0.5% Cu conductor. Finally, a four-layer multi-layer magnetic film was formed so that the easy axis of magnetization of the upper magnetic body coincided with that of the lower magnetic body. The lower magnetic body undergoes various heating and cooling processes during device fabrication, but the effect of such heat on the magnetic properties is extremely small, and the heat resistance of the magnetic body is good, and The magnetic characteristics after device formation were almost the same. When the electrical characteristics of the thin-film inductor thus formed were evaluated, the inductance L was 2 μH and the quality factor Q was 15 (5 MHz). Moreover, when the DC superposition characteristics were measured, the inductance was DC current 150 mA.
Was flat and dropped at 200 mA or more.

As the coil flattening insulating film, substantially the same electrical characteristics were obtained when polyimide was used and when an SiO ₂ film was formed by a CVD method using organic silane or a bias sputtering method. .

Example 25 A thin film type transformer was produced in the same manner as in Example 24. The number of turns of the primary side spiral coil is 20, and the number of turns of the secondary side spiral coil is 10. The primary and secondary spiral coils were insulated with a 2 μm polyimide layer. The thin film transformer has exactly the same structure as the thin film inductor of the twenty-fourth embodiment except for the secondary spiral coil. The direct current superposition characteristic of the primary side inductance was almost the same as that of the thin film inductor of Example 24.

Example 26 The planar inductor produced in Example 22 was used with an input voltage of 12
It was applied to the output side choke coil of a step-down chopper type DC-DC converter with V and an output voltage of 5V. This converter has a switching frequency of 500 kHz and a load current of 4
Can output up to 00mA, maximum output current 2W,
An efficiency of 80% was obtained.

Example 27 The flat transformer manufactured in Example 23 was supplied with an input voltage of 12V,
Example 22 is applied to a transformer of a forward type DC-DC converter with an output voltage of 5 V, and the output side choke coil is the embodiment 22.
The planar inductor manufactured in 1. was used. The switching frequency was 500 kHz and the rated output was equivalent to that of the DC-DC converter of Example 26, and the insulation type DC-DC converter could be miniaturized.

Example 28 The thin film inductor prepared in Example 24 was used with an input voltage of 12
It was applied to the output choke coil of a step-down chopper type DC-DC converter with V and an output voltage of 5V. This converter has a switching frequency of 4 MHz and a load current of 1
Can output up to 50mA, maximum output current 0.7
5W and 70% efficiency were obtained.

Example 29 The thin film type transformer manufactured in Example 25 was used with an input voltage of 12
The thin film inductor of Example 24 was used for the output choke coil, which was applied to a transformer of a flyback DC-DC converter with V and an output voltage of 5V. The rated output is almost the same as that of the DC-DC converter of the twenty-eighth embodiment, but since all the magnetic parts are made thin, the isolated DC-DC
The size and weight of the converter have been greatly reduced.

Example 30 An example of the fifth means will be shown.

10 on a 10 μm thick polyimide film
After bonding a copper foil having a thickness of 0 μm, wet chemical etching using ferric chloride was performed to obtain a shape as shown in FIG.
Zero 1-turn flat coils were formed and 20 external terminal pad portions were provided. The width of the coil conductor was 300 μm, and the interval between the coil conductors was 100 μm. The outermost one-turn planar coil has an outer dimension of 9 mm, and the innermost one-turn planar coil has an outer dimension of 1.8 mm. A polyimide film having a thickness of 10 μm was bonded onto the flat coil. This was sandwiched between zero-magnetostrictive Co-based amorphous alloy foils having a side of 10 mm and a thickness of 10 μm to fabricate a planar magnetic element.

(A) A planar inductor similar to the spiral coil type was constructed by connecting the external connecting terminals of the planar coil by the connecting method shown in FIG. 52 using the produced planar magnetic element. When the planar inductor was measured with an LCR meter, the inductance value at 500 kHz was about 20 μH and the Q value was about 10.

When this planar inductor was applied to the output choke of a hybrid IC type DC-DC converter operating at 500 kHz switching, it was confirmed to operate normally. This has allowed us to develop a thin DC power supply.

Further, this planar inductor was applied to a DC bias supply line high frequency blocking filter of a power MOSFET of a 20 MHz nonlinear power amplifier. By adopting this element, the power line filter can be made extremely small.

(B) A pseudo zigzag folded coil type planar inductor was constructed by connecting the external connecting terminals of the planar coil by the connecting method shown in FIG. 51 using the produced planar magnetic element. When the planar inductor was measured with an LCR meter, the inductance value was about 300 nH.
This planar inductor had good frequency characteristics up to several tens of MHz.

When this planar inductor was used for the output side low-pass filter of the 20 MHz nonlinear power amplifier, it was possible to realize a significantly smaller size than the conventional filter using the air-core coil.

(C) Using the produced planar magnetic element, a transformer was formed by connecting the external connection terminals of the planar coil by the connection method shown in FIG. The total number of turns of the primary plane coil was 7, and the total number of turns of the secondary plane coil was 2. When the transformer ratio of this transformer was measured, it was about 0.2.
It was 5.

(D) The manufactured planar magnetic element was set to 1 MHz.
It was used as a matching transformer for the power amplifier. The output impedance of this power amplifier is 200Ω. As a result of trying various terminal connections to match a 50Ω load,
We were able to obtain almost satisfactory results. Such matching adjustment is impossible with the conventional plane transformer.

Example 31 Fe having a thickness of 3 μm was formed on a silicon substrate by RF sputtering.
A 40Co60 alloy film was formed, and a 1 μm thick SiO ₂ film was formed on the 40Co60 alloy film by the RF sputtering method. Further, an Al—Cu alloy having a thickness of 10 μm was formed by DC magnetron sputtering method. This Al-Cu alloy was etched by magnetron-type reactive ion etching using the SiO ₂ pattern as a mask, and 10 1-turn plane coils were patterned. The external connection terminals are shown in FIG. 49 and FIG.
One of each of the two types of arrangement shown in 0 was formed. The width of the coil conductor was 200 μm, and the interval between the coil conductors was 5 μm. The outer dimension of the outermost 1-turn plane coil is 4.5 mm, and the outer dimension of the innermost 1-turn plane coil is 0.81 mm. After the SiO ₂ was buried on the Al—Cu pattern by the plasma CVD method, the upper surface of the SiO ₂ was flattened by the resist etch back method. Finally, Fe40 with the same thickness of 3 μm as the lower magnetic film
A Co60 alloy film was formed to produce a planar magnetic element.

(A) Of the manufactured planar magnetic elements, FIG.
Single-in-line package type (SIP) 20-pin element shown in FIG. 67 by using the one-sided external terminal type magnetic element shown in FIG. 9 and connecting the external connection terminal to the lead frame through the bonding wire, and then sealing with resin. Was produced.

By combining this element with a semiconductor relay,
It is possible to adjust the inductance in multiple stages from the outside using an electronic circuit. As a result, the adjustment function of the element could be further facilitated.

(B) Of the manufactured planar magnetic elements, FIG.
A dual in-line package type (DIP) 40-pin element shown in FIG. 68 was produced in the same manner as above using the double-sided external terminal type magnetic element shown in FIG.

By combining this element with a semiconductor relay,
The transformation ratio can be adjusted in multiple stages from the outside using an electronic circuit. As a result, the adjustment function of the element could be further facilitated.

(C) SIP type 20 similar to (a)
When the pin inductor element was manufactured, it was packaged in a Mn-Zn ferrite package instead of being sealed with resin. The inductance value of this element doubled as compared with the element of (a).

As an application of this circuit, a step-up chopper type DC-DC converter, a step-down chopper type DC-
DC converter, rf circuit for ultra-thin mobile phones, resonance type D
There is a C-DC converter or the like. As an example of the circuit diagram, FIG. 69 shows a step-up chopper type DC-DC converter,
FIG. 70 shows a step-down chopper type DC-DC converter, and FIG.
1 shows the rf circuit of an ultra-thin mobile phone, and Fig. 72 shows a resonance type DC-
A DC converter is shown.

Example 32 A one-turn type planar inductor having the structure shown in FIG. 62A was manufactured. A Si substrate is used as the substrate, the conductor is Al,
The insulator is silicon oxide.

The parameters in FIG. 62A are as follows according to the symbols in FIG. 62B. d1 = 1 × 10 ^-3 (m), d2 = 5 × 10 ^-3 (m) δ1 = 1 × 10 ^-6 (m), δ2 = 1 × 10 ^-6 (m) μs = 10 4, ρ = 2. 65 × 10 ^-8 (Ωm) d3 = 14 × 10 ^-6 (m) Various characteristics of the inductor thus prepared are as follows: L = 32 (nH) RDC = 14 (mΩ) Imax = 630 (mA) Q1MHz = 15 , Q10MHz = 150. It should be noted that Q represents a quality factor and represents an L component ratio that works effectively with respect to a DC resistance component, and a larger value can be said to be an excellent inductor.

It was also confirmed that there was almost no leakage magnetic field.

For reference, the same outer shape (d2 = 5 × 10 ⁻³⁾
(M), d3 = 14 × 10 ⁻⁶ (m)) a planar spiral coil (the number of turns was 125) was prepared and the characteristics were compared. The sectional shape is shown in FIG. 73. The magnetic body 30 is arranged on the upper and lower surfaces of the conductor 45.

The various characteristics of the inductor thus produced were: L = 900 (μH) RDC = 600 (Ω) Imax = 6.4 (mA) Q1MHz = 9, Q10MHz = 90.

As can be seen from these results, the one-turn type coil has a large current capacity and is effective for electric power that requires a large current. Moreover, although the inductance itself is small, it can be sufficiently covered by increasing the frequency in terms of impedance.

[0303]

As described in detail above, each means of the present invention has the following effects according to the present invention.

In the planar magnetic element according to the first means of the present invention, by reducing the coil resistance, Q can be improved in the inductor and the gain and voltage fluctuation rate can be improved in the transformer, and the performance of these elements can be improved. Contribute significantly to.

In the second means of the present invention, when an inductor is considered, its performance is determined by the allowable current and the magnitude of the inductance. The allowable current is determined by the cross-sectional area of the conductors forming the coil, but widening the width increases the occupied area accordingly, which is against the demand for miniaturization. Further, the inductance increases as the number of turns increases, but the occupied area also increases, which also goes against the demand for miniaturization. Therefore,
By this means, it is possible to take a large allowable current.

In the third means of the present invention, when designing the planar inductor, the inductance should be as large as possible. Like this means, the external dimension w of the magnetic body
The inductance can be effectively increased by making 2α (α is as described above) or more larger than the outer dimension a0 of the spiral coil. For example, by setting w = a0 + 2α, a value more than 1.8 times that in the case of w = a0 can be obtained.

As described above, when the spiral type planar inductor is constructed by this means, the leakage magnetic flux to the outside of the inductor can be reduced and the effect of increasing the inductance can be expected, which greatly contributes to the performance improvement of the planar inductor. To do.

Further, the plane inductor according to the present means is suitable for an integrated circuit element because it has a high inductance and can reduce a leakage magnetic flux, and greatly contributes to downsizing and thinning of electronic equipment.

The flat type magnetic element according to the fourth means of the present invention is excellent in direct current superimposition characteristics and high frequency characteristics by effectively utilizing the uniaxial magnetic anisotropy of the magnetic material, and particularly DC-D.
It is suitable for high-frequency circuits such as C converters, and can be miniaturized and integrated.

The flat magnetic element of the fifth means of the present invention is extremely easy to electrically connect to an external circuit, and the electrical characteristics can be trimmed from the outside. Therefore, it is a magnetic component extremely useful for application of the element. Becomes As the application of this magnetic element, for example, the step-up chopper type DC-DC converter, the step-down chopper type DC-DC converter, the rf circuit of the ultra-thin mobile phone, and the resonance type DC-D have been shown in the above-mentioned embodiments.
There is a C converter and the like.

According to the magnetic element of the sixth means of the present invention,
By providing a structure that has no leakage magnetic field and has a large current capacity, this also contributes greatly to downsizing.

Due to the effects of the invention by each of the above means, it is possible to reduce the size of the magnetic element, and the various characteristics required for a planar inductor or the like are also improved.

According to the effect of the sixth means of the present invention, by forming a planar inductor and a transformer made of a planar microcoil as a magnetic element on a semiconductor substrate, for example, active elements such as transistors, resistors, capacitors, etc. It is possible to form a single chip with the passive element, and it is possible to downsize the electric element including the planar inductor and the transformer. Further, by using the semiconductor fine processing technique, the planar inductor and the transformer itself can be downsized.

Therefore, according to the present invention, the conventional card,
Since the inductance portion, which has been an obstacle to downsizing, can be downsized and thinned, it can contribute to downsizing of the entire device.

[Brief description of drawings]

FIG. 1 is a schematic view of a conventional planar inductor using an amorphous magnetic foil and a square spiral coil.

FIG. 2 shows an example of a waveform of a current flowing through an output choke coil of a conventional DC-DC converter.

FIG. 3 is a BH curve of a conventional magnetic material.

FIG. 4 shows an example of DC superposition characteristics of a conventional inductor.

FIG. 5 is an exploded perspective view of the planar inductor according to the present invention.

FIG. 6 is a schematic cross-sectional view of a planar inductor according to the present invention.

FIG. 7 is an exploded perspective view of a flat transformer according to the present invention.

FIG. 8 is a schematic sectional view of a flat transformer according to the present invention.

FIG. 9 is a graph showing the relationship between the groove aspect ratio and the coil resistance and inductance of the planar inductor.

FIG. 10: Groove aspect ratio and L / R of planar inductor
A graph showing the relationship with.

FIG. 11 is a graph showing the relationship between the groove aspect ratio and the gain of the planar transformer.

12A is an exploded perspective view of a magnetic element having a high conductor aspect ratio and a high groove aspect ratio in which the first and second means are combined, and FIG. 12B is a sectional view of FIG. 12A.

13A to 13D are process diagrams showing manufacturing steps of a method for forming a cavity between conductors.

FIG. 14 is a process drawing showing a manufacturing process of a method for forming a cavity between conductors.

FIG. 15 is a schematic view of a parallel plate capacitor.

FIG. 16 is a graph showing the k dependence of C / C0.

FIG. 17 is a diagram in which a coil is sandwiched by magnetic materials.

FIG. 18 is a diagram in which a coil is multilayered with an insulator interposed.

FIG. 19 is a diagram showing a modified example of the coil pattern.

FIG. 20 is a diagram in which a bonding layer is provided between a conductor and a substrate.

FIG. 21 is a diagram showing a configuration example of a micro transformer.

FIG. 22 is a diagram showing a configuration example of a planar coil.

FIG. 23 is an exploded perspective view showing a configuration example of an inductor.

FIG. 24 is an exploded perspective view showing a configuration example of an inductor.

FIG. 25A to FIG. 25C are cross-sectional views of the inductor showing a state of leakage magnetic flux to the outside of the inductor.

FIG. 26 is a graph showing a magnetic field distribution in the vicinity of an end portion of a planar inductor spiral coil.

FIG. 27 is a graph showing the relationship between the external dimension w of the magnetic body and the magnetic flux leaked from outside the inductor.

FIG. 28 is a graph showing the relationship between the external dimension w of the magnetic body and the inductance.

FIG. 29 is an exploded perspective view of a planar inductor in which uniaxial magnetic anisotropy is introduced in a magnetic layer.

30 is an explanatory diagram showing the relationship between the direction of the magnetic field generated by the coil and the direction of uniaxial magnetic anisotropy in the plane of the magnetic layer of the planar inductor of FIG.

FIG. 31 is a diagram showing magnetization curves of a magnetic material in the easy axis direction and the hard axis direction.

32A is a diagram showing a magnetic flux distribution in a magnetic body region in which the direction of the magnetic field is parallel to the direction of the easy axis of magnetization in FIG. 30, and FIG. 32B is the direction of the magnetic field and the direction of the easy axis of magnetization in FIG. FIG. 6 is a diagram showing a magnetic flux distribution in a magnetic material region where

FIG. 33 is an exploded perspective view of the planar inductor according to the present invention.

34 is a diagram showing DC superimposition characteristics of the planar inductor shown in FIG. 33.

FIG. 35 is an exploded perspective view of the planar inductor of the modification example of FIG. 33.

FIG. 36 is an exploded perspective view of another planar inductor according to the present invention.

37 is a diagram showing DC superimposition characteristics of the planar inductor shown in FIG. 36.

FIG. 38 is an exploded perspective view of still another planar inductor according to the present invention.

39 is a perspective view showing the surface structure of a magnetic layer that constitutes the planar inductor of FIG. 38. FIG.

FIG. 40 is a diagram showing the relationship between the surface structure parameter of the magnetic layer of FIG. 39 and the second term of Uk.

41 is a diagram showing DC superimposition characteristics of the planar inductor shown in FIG. 37.

42A is a diagram showing a magnetization curve in the easy axis direction and the hard axis direction of a magnetic material, and FIG. 42B is a permeability-frequency characteristic of the easy axis and the hard axis of a magnetic material having uniaxial magnetic anisotropy. An example.

FIG. 43 is a schematic view of a planar inductor in the example of the planar magnetic element according to the first embodiment of the present invention.

FIG. 44 is a modification of FIG. 43.

FIG. 45 is a schematic view of a planar inductor in the example of the planar magnetic element according to the second embodiment of the present invention.

FIG. 46 is a modification of FIG. 45.

FIG. 47 is a modification of FIG. 46.

FIG. 48 is a schematic view of a planar inductor in which a magnetic shield magnetic material is formed in a portion where a coil conductor is exposed.

FIG. 49 is a plan view of a magnetic element according to the present invention.

FIG. 50 is a plan view of another magnetic element according to the present invention.

51 is a plan view of a planar inductor manufactured by connecting external connection terminals of the magnetic element of FIG. 49. FIG.

52 is a plan view of another planar inductor manufactured by connecting the external connection terminals of the magnetic element of FIG. 49. FIG.

FIG. 53 is a plan view of still another planar inductor produced by connecting the external connection terminals of the magnetic element of FIG. 49.

54 is a graph showing the relationship between the connection method of the external connection terminals of the magnetic element of FIG. 49 and the inductance value.

55 is a plan view of a flat transformer manufactured by connecting the external connection terminals of the magnetic element of FIG. 49. FIG.

FIG. 56 is a plan view of another plane transformer manufactured by connecting the external connection terminals of the magnetic element of FIG. 49.

57 is a plan view of still another planar transformer manufactured by connecting the external connection terminals of the magnetic element of FIG. 49. FIG.

FIG. 58 is a graph showing the relationship between the connection method of the external connection terminals of the magnetic element of FIG. 49 and the transformation ratio and the current transformation ratio.

FIG. 59 is a cross-sectional view of an element in which an active element and a magnetic element are formed on the same plane on a semiconductor substrate.

FIG. 60 is a cross-sectional view of an element in which an active element and a magnetic element are sequentially formed on a semiconductor substrate.

FIG. 61 is a cross-sectional view of an element in which a magnetic element and an active element are sequentially formed on a semiconductor substrate.

62A is a cross-sectional view of a one-turn structure coil, and B is a structural diagram of a one-turn structure coil. FIG.

63A is a diagram in which the coils of FIG. 62A are connected in series, FIG.
B is the figure which laminated | stacked the coil of FIG. 63A.

64 is a cross-sectional view when a conductor layer and an insulator layer are added to the coil of FIG. 62A.

FIG. 65 is a reference diagram for explaining selection criteria of magnetic material, and shows the relationship between the number of turns of the spiral planar coil, the maximum allowable current of the coil conductor, and the magnetic field generated when the maximum allowable current is passed through the coil conductor. FIG.

FIG. 66 is a schematic view of a pager manufactured using the magnetic element of the present invention.

FIG. 67 is a plan view of a single in-line package type (SIP) 20-pin element manufactured in the example of the present invention.

FIG. 68 is a perspective view of a dual in-line package type (DIP) 40-pin device manufactured in the example of the present invention.

FIG. 69 is a circuit diagram of a step-up chopper type DC-DC converter.

FIG. 70 is a circuit diagram of a step-down chopper type DC-DC converter.

71 is an rf circuit diagram of an ultrathin mobile phone. FIG.

FIG. 72 is a circuit diagram of a resonant DC-DC converter.

FIG. 73 is a cross-sectional view according to one embodiment of the present invention.

[Explanation of symbols]

10 substrates 20 Insulator layer 30 Magnetic layer 40 plane coil 50 Protective layer

   ─────────────────────────────────────────────────── ─── Continued front page    (31) Priority claim number Japanese Patent Application No. 3-91614 (32) Priority date March 29, 1991 (March 29, 1991) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-93434 (32) Priority date March 30, 1991 (March 30, 1991) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-93717 (32) Priority date March 30, 1991 (March 30, 1991) (33) Priority claiming country Japan (JP) (72) Inventor Masashi Sahashi               1 Komukaishiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa               Toshiba Research Institute, Ltd. (72) Inventor Mio Hasegawa               1 Komukaishiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa               Toshiba Research Institute, Ltd. (72) Inventor Atsuhito Sawabe               1 Komukaishiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa               Toshiba Research Institute, Ltd. (72) Inventor Hiroshi Tomita               1 Komukaishiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa               Toshiba Research Institute, Ltd.                (56) Reference JP-A-57-52114 (JP, A)                 Japanese Patent Laid-Open No. 1-310518 (JP, A)                 JP-A-1-157507 (JP, A)

Claims (10)

(57) [Claims] 1. A step of forming a first magnetic layer on a substrate by a thin film process, a step of forming a first insulator layer on the first magnetic layer by a thin film process, and the first insulator layer. A step of forming a flat coil having a groove aspect ratio between adjacent coil conductors of 1 or more (a thickness of the coil conductor / a distance between the coil conductors) by a thin film process; and a second step on the flat coil. A step of forming an insulator layer by a thin film process; and a step of forming a second magnetic layer on the second insulator layer by a thin film process, wherein the coil is formed in the step of forming the second insulator layer. A method of manufacturing a planar magnetic element, characterized in that a cavity is formed between conductors. 2. A conductor aspect ratio (thickness of coil conductor / width of coil conductor) such that the ratio of the line height to the line width of the plane coil is 1 or more in the step of forming the plane coil.
The method of manufacturing a planar magnetic element according to claim 1, further comprising the step of forming a planar coil having: 3. The method of manufacturing a planar magnetic element according to claim 1, further comprising the step of forming a cavity in a groove between adjacent conductors of the planar coil. 4. The plane coil has a spiral shape and w ≧ a0 + 2α, w is an outer dimension of the first and second magnetic layers, a0 is an outer dimension of the coil conductor of the plane coil, and α = [Μs · g · t / 2] 1/2 (μs is the magnetic permeability of the first and second magnetic layers, t is the thickness of the first and second magnetic layers, and g is the first and second magnetic layers) The distance between the second magnetic layers)).
A method of manufacturing the planar magnetic element according to [4]. 5. The first and second magnetic layers have uniaxial magnetic anisotropy in a direction orthogonal to a direction of a magnetic field generated by the planar coil. A method of manufacturing the planar magnetic element according to [4]. 6. The planar coil includes a plurality of rectangular spiral coils, and a long axis of the planar coil and an easy axis of magnetization of the first and second magnetic layers having uniaxial magnetic anisotropy coincide with each other. 3. The method for manufacturing a flat magnetic element according to claim 1 or 2. 7. The planar coil includes a plurality of rectangular spiral coils connected in series, and the easy axis of magnetization of the first and second magnetic layers having a major axis direction of the planar coil and uniaxial magnetic anisotropy. 3. The method for manufacturing a planar magnetic element according to claim 1 or 2, characterized in that 8. The method of manufacturing a planar magnetic element according to claim 1, wherein the thin film process is a process by vapor deposition , sputtering or CVD. 9. The flat magnetic element according to claim 3, wherein the cavity is formed by using a process by a CVD method or by sputtering insulating particles from an oblique direction with respect to the substrate. Manufacturing method. 10. A planar magnetic element manufactured by the manufacturing method according to claim 1, and at least one of an active element and a passive element are formed on the substrate. A semiconductor device characterized by the above.