JPH0963844A - Multilayered magnetic film and thin film magnetic element employing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a multilayered magnetic film including an insulation layer of low resistivity and low permittivity by providing a magnetic layer exhibiting uniaxial magnetic anisotropy in the plane, and an insulation layer principally comprising Mg and O abutting against the magnetic layer. SOLUTION: An insulation layer 2 principally comprising Mg and O is provided while abutting against a magnetic layer 1 exhibiting uniaxial magnetic anisotropy in the plane. The magnetic layer 1 exhibiting uniaxial magnetic anisotropy in the plane and the Mg-O based insulation layer 2 are laminated repetitively to produce a multilayer magnetic film. In each magnetic film, an amorphous magnetic layer containing Fe, Co, B and a group 4b element as principal constituents, or a magnetic layer comprising a mixed phase of microcrystalline phase and amorphous phase is employed as the magnetic layer 1. Consequently, a multilayer magnetic film subjectable to wet etching can be obtained while imparting and controlling the high saturation magnetization, low loss, and in-plane uniaxial anisotropy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated magnetic film used for a thin film inductor, a thin film transformer and the like, and a planar magnetic element using the laminated magnetic film.

[0002]

2. Description of the Related Art In recent years, miniaturization of various electronic devices has been actively promoted, but miniaturization of a power supply section of electronic devices has been delayed compared with that. For this reason, the volume ratio of the power supply unit to the entire device is increasing. The miniaturization of electronic devices is largely due to the LSI implementation of various circuits, but miniaturization and integration of magnetic components such as inductors and transformers, which are indispensable for power supply units, has been delayed, which is the main reason for the increase in volume ratio. Has become.

In order to solve such a problem, a flat type magnetic element (thin film magnetic element) in which a flat coil and a magnetic film are combined has been proposed, and studies for improving its performance are being advanced. The magnetic thin films used for these are required to have low loss and high saturation magnetization in a high frequency region of 1 MHz or higher. By the way, in the high frequency region, the magnetic permeability is mainly covered by the rotating magnetization process. In order to obtain an ideal rotational magnetization process, it is necessary to excite in the hard axis direction under uniform in-plane uniaxial magnetic anisotropy, and magnetic permeability and coercive force in the hard axis direction are important. It becomes a physical property value.

The high frequency magnetic permeability is a quantity complicatedly related to various physical properties of the sample, and the one having the highest correlation is the anisotropic magnetic field. The high frequency magnetic permeability is generally proportional to the reciprocal of the anisotropic magnetic field. . In magnetic elements such as thin film inductors,
Since the optimum permeability changes according to each design,
In order to achieve high magnetic permeability suitable for magnetic elements such as thin film inductors in the high frequency range, it is necessary to have uniaxial magnetic anisotropy in the magnetic film plane and controllability of anisotropic magnetic field. is there.

Further, in order to realize high frequency and low loss, it is necessary to reduce the eddy current loss. For this purpose, it is effective to make the magnetic layer thin. If the film thickness required for the design of the magnetic element is too large from the viewpoint of reducing eddy current loss, it is effective to insert a high-resistivity layer between a plurality of thinned magnetic layers. . It is desirable that this layer has a high resistivity, a high withstand voltage, and a low dielectric constant.

Further, magnetic elements such as thin film inductors are
Higher saturation magnetization of the magnetic film is expected to increase the electric power that can be handled and the saturation current. Therefore, high saturation magnetization is also necessary for magnetic films for magnetic elements such as thin film inductors.

Even in a thin film magnetic head or the like, magnetic properties having low loss and high saturation magnetization in a high frequency region are accompanied by an increase in recording density, a high coercive force of a medium, a high energy product and a high operating frequency. It goes without saying that the membrane is effective. These requirements are generally common to other magnetic elements.

On the other hand, in the manufacturing process of the magnetic element, the process compatibility of the magnetic film and the laminated magnetic film becomes a problem. When forming a large number of magnetic elements on a substrate by using a general thin film process technology, a magnetic film is formed for the purpose of forming electrodes, forming slits of magnetic films, forming through holes, separating each element, and realizing a designed magnetic circuit. It becomes necessary to pattern.
Patterning is generally done after forming a mask by various methods,
It is performed by dry etching or wet etching. Particularly, in consideration of mass productivity, wet etching is more preferable because the equipment is inexpensive and a large amount of stable and easy etching can be realized even in actual production. In the magnetic layer having a high saturation magnetization, metal atoms generally occupy most of the composition, and therefore there is almost no problem in terms of the type of etchant and etching rate.

However, in the case of forming the laminated magnetic film, many constituent materials of the insulating layer interposed between the magnetic layers have strong covalent bond and ionic bond, and often have low wet etching property. For example, SiO ₂ which is generally used as an interlayer insulating layer is an excellent insulating layer that can obtain good insulating properties relatively easily, but when wet etching, a dangerous and special etchant such as HF is used. Inadequate process compatibility as required.

On the other hand, the interlayer insulating layer of the laminated magnetic film is also required to have low reactivity with the magnetic layer. The magnetic layer material of the laminated magnetic film is usually optimized for spontaneous magnetization and minimized coercive force according to the specifications of the applied inductor or the like. On the other hand, when a magnetic element having a laminated magnetic film as a constituent element is manufactured by various thin film processes, the magnetic layer itself or various materials above and below are formed, or when the resin material is cured, The element substrate itself becomes hot. Further, heat treatment is often applied to control the magnetic characteristics of the laminated magnetic film. For these high temperature processes, it is necessary to select the interlayer insulating layer that minimizes the reaction with the magnetic layer and can practically ignore the formation of the interface layer that inhibits soft magnetism and high spontaneous magnetization and the mutual diffusion of atoms. There is.

From the viewpoint of the precise control of the high frequency magnetic permeability described above, that is, the precise assignment and control of the in-plane uniaxial magnetic anisotropy, the contamination of elements other than the original constituent elements of the magnetic layer to the magnetic layer is prevented. It has a non-negligible effect on the induction of magnetic anisotropy. Therefore, from the viewpoint of precise control of magnetic properties, particularly magnetic anisotropy, the interlayer insulating layer is required to have particularly excellent non-reactivity with the magnetic layer. However, although oxides such as Zr, Ta, and Nb have excellent insulating properties, they are likely to react with the magnetic layer during the high temperature process as described above, resulting in deterioration of the characteristics of the magnetic layer.

[0012]

As described above, in order to miniaturize and improve the performance of a planar magnetic element such as a thin film inductor, the magnetic film used for it has low loss and high loss in the high frequency region of 1 MHz or more. High saturation magnetization is required. In order to satisfy such required characteristics, for example, in order to realize high frequency and low loss, it is effective to stack a thin magnetic layer via an interlayer insulating layer, but it has been conventionally used. Among the interlayer insulating layers, SiO ₂ has a drawback that it has low suitability for wet etching, which is excellent in mass productivity. On the other hand, oxides such as Zr, Ta, and Nb have a drawback that diffusion and the like with the magnetic layer occur during a high temperature process, and there is a high possibility that the characteristics of the magnetic layer will deteriorate.

As described above, in consideration of the manufacturing process of a planar magnetic element or the like, the interlayer insulating layer forming the laminated magnetic film is suitable for wet etching, which is excellent in mass productivity, and is excellent in magnetic layer. Both non-reactivity is required,
As described above, conventional interlayer insulating layer materials have not yet reached all of these required characteristics. For this reason, wet etching is possible while maintaining high saturation magnetization, soft magnetism, and in-plane uniaxial magnetic anisotropy imparting / controllability of the magnetic layer, and it does not react with the magnetic layer even after a high temperature process. The inter-layer insulation layer is eagerly awaited.

The present invention has been made to solve such a problem, and wet etching is performed while maintaining high saturation magnetization, soft magnetism, and in-plane uniaxial magnetic anisotropy imparting / controllability of the magnetic layer. In addition to the above, it is an object of the present invention to provide a laminated magnetic film having an insulating layer having a high resistivity and a low dielectric constant, which has extremely low reactivity with a magnetic layer, and a planar magnetic element using the same.

[0015]

The laminated magnetic film of the present invention comprises:
As described in claim 1, a magnetic layer having in-plane uniaxial magnetic anisotropy, and a Mg layer arranged in contact with the magnetic layer.
And an insulating layer containing O as a main component, or as described in claim 2, Fe as a main constituent element,
It is characterized by comprising a magnetic layer containing Co, B and 4B group elements, and an insulating layer containing Mg 2 O 3 as a main component and being laminated in contact with the magnetic layer. The insulating layer containing Mg and O as the main components, which is used as an interlayer insulating layer in the laminated magnetic film of the present invention, has excellent wet etching properties, and thus can be mass-produced and can also be used in the Fe-Co-B-4B group. Since it has excellent non-reactivity to various magnetic layers including the system-based amorphous magnetic layer, it gives the in-plane uniaxial magnetic anisotropy, which is essential for planar magnetic elements such as thin film inductors, and control characteristics. , Magnetic properties such as coercive force and spontaneous magnetization are not impaired in practical use.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Modes for carrying out the present invention will be described below.

FIGS. 1, 2 and 3 are views showing an embodiment of a laminated magnetic film of the present invention, respectively, which are used as a soft magnetic film of a planar magnetic element such as a planar inductor or a planar transformer. It is a thing. Of these, Figure 1
FIG. 1 is a diagram showing the minimum necessary constitutional unit of the laminated magnetic film of the present invention, and 1 is a magnetic layer having in-plane uniaxial magnetic anisotropy. Insulating layers (hereinafter referred to as Mg—O based insulating layers) 2 as a component are laminated and arranged. Note that reference numeral 3 in FIG. 1 denotes a substrate, and the Mg—O based insulating layer 2 in the laminated magnetic film shown in FIG. 1 functions as, for example, an underlayer or a buffer layer.

FIG. 2 shows a laminated magnetic film having a repetitive structure in which a magnetic layer 1 having in-plane uniaxial magnetic anisotropy and an Mg—O type insulating layer 2 are laminated in order, and the number of repeated laminations is set arbitrarily. be able to. The laminated magnetic film in which such a thin magnetic layer 1 is laminated via the Mg—O based insulating layer 2 functioning as an interlayer insulating layer is effective for realizing high frequency and low loss as described above. .

As shown in FIG. 3, the laminated magnetic film of the present invention includes, as constituent elements, a third layer 4 and the like different from these in addition to the magnetic layer 1 and the Mg—O based insulating layer 2. Good.
It is also possible to adopt a structure other than these,
The laminated magnetic film of the present invention can take various forms as long as it has the magnetic layer 1 and the Mg—O based insulating layer 2 that is arranged in contact with the magnetic layer.

In each of the above-mentioned laminated magnetic films, a soft magnetic material having high in-plane uniaxial magnetic anisotropy imparting and controllability is used as the magnetic layer 1 having both high saturation magnetization and soft magnetism. In-plane uniaxial magnetic anisotropy is imparted by the method.
Examples of such a magnetic layer 1 include Fe, Co, B and
Examples thereof include an amorphous magnetic layer containing a Group 4B element as a main constituent element, a magnetic layer composed of a mixed phase of a microcrystalline phase and an amorphous phase composed of similar elements, and the like. In addition, as a 4B group element
One or more elements selected from C, Si, Ge, Sn, etc. are used. All of these are magnetic layers capable of obtaining good soft magnetism and high spontaneous magnetization, and are magnetic layers particularly suitable for the present invention. However, in the present invention, it is possible to use various other magnetic layers such as a Fe—Co—Sn based microcrystalline magnetic layer.

The Mg-O type insulating layer 2 has an excellent wet etching property suitable for a mass production process and has a high resistivity and a low dielectric constant which are basic characteristics as an insulating layer. is there. After satisfying these characteristics, Mg-O
The system insulating layer 2 has sufficient adhesion to various magnetic layers 1 including the Fe-Co-B-4B group amorphous magnetic layer and has almost no influence on the magnetic layer 1. It has the property of not being. In the manufacturing process of a planar magnetic element such as a thin film inductor, during the formation of the magnetic layer 1, the formation of a layer in contact with the magnetic layer 1, the heat treatment, etc.
However, when the Mg-O insulating layer 2 is used, the influence of the diffusion on the magnetic characteristics can be neglected in practical use. This is because Mg hardly forms a solid solution with Fe-Co, and Mg is more easily oxidized than Fe-Co.
It is considered that this is because oxygen itself is also difficult to diffuse.

Diffusion at the interface is generally preferable from the viewpoint of adhesion, but, for example, Fe-Co-B-4B group magnetic materials are materials that have been sufficiently soft magnetized, so that diffusion of different elements is possible. And a change in the composition ratio due to diffusion of the same kind of elements hinders the soft magnetism and decreases the saturation magnetization. Further, even when soft magnetic deterioration is not fatal, the magnitude of the induced magnetic anisotropy and the heat treatment temperature of the induced magnetic anisotropy are given when the uniaxial magnetic anisotropy is given and controlled by the heat treatment in a magnetic field described later. Dependence, activation energy that affects reaction time, and the like change due to diffusion. These make precise and theoretically clear anisotropy control difficult.

This is for the following reason. Although Fe-Co-B-4B group magnetic materials can generate induced magnetic anisotropy according to the theory of directional ordered arrangement, the induced magnetic anisotropy obtained after sufficient heat treatment is a function of heat treatment temperature. Is. On the other hand, when the diffusion at the interface is remarkable, the diffusion state also changes depending on the heat treatment temperature, so that the composition ratio of the magnetic layer 1 also changes depending on the temperature, and accurate anisotropy control cannot be performed by the usual theory of directional ordered arrangement. . This is a phenomenon common to magnetic layers other than the Fe-Co-B-4B group magnetic materials.

Further, the Fe-Co-B-4B group magnetic material has an exceptionally large magnetostriction as a soft magnetic film, and besides the directional ordered arrangement, a mechanism for controlling magnetoelastic energy through magnetostriction,
That is, the in-plane magnetic anisotropy can be controlled by the magnetostriction constraint effect. The introduction of these anisotropic stresses is controlled by applying a magnetic field during film formation, anisotropic stress application to the substrate itself, anisotropic release of stress by anisotropic patterning of the magnetic film, and the like. Also in these in-plane magnetic anisotropy control, the anisotropy energy changes due to the change of the magnetostriction constant. The magnetostriction constant is compositionally sensitive, and diffusion of the insulating layer element causes a change in the magnetostriction constant, that is, an anisotropic energy change. From this point as well, the Mg—O-based insulating layer 2 that does not substantially cause diffusion at the interface with the magnetic layer 1 is effective.

From the above, when the Mg—O type insulating layer 2 is used as an interlayer insulating layer which is in contact with the magnetic layer 1,
In imparting and controlling the magnetic anisotropy required for a planar magnetic element such as a thin film inductor, the original magnetic anisotropy control characteristics of the magnetic layer 1, coercive force, spontaneous magnetization and other magnetic characteristics are not impaired in practical use.

Further, a fixed amount of a metal element other than Mg, a fixed amount of a non-metal element other than oxygen, or a combination of both of them is added to the Mg-O insulating layer 2. The film quality such as film stress and adhesion force, the linear expansion coefficient, and the fine structure of the film that are introduced during the formation of the insulating layer 2 may be controlled. The physical properties of these Mg-O insulating layers 2 do not greatly affect the magnetic characteristics when only the laminated magnetic film is used, but planar magnetic elements such as thin film inductors (thin film magnetic devices)
It is especially important from the viewpoint of process compatibility and device electromagnetic characteristics. However, in this case, in order to suppress diffusion of a non-metal element typified by oxygen into the magnetic layer 1 as much as possible, a non-metal element containing oxygen (groups 5B and 6B).
The total sum NM of the products of the absolute value of the ion valence and the molar concentration of each element of the group (elements contained in the 7B group) is Mg-containing metal elements (1A group, 2A group, 3A group, 4A group, 5A group, 6A, 7A, 8
It is preferable that the composition is such that the sum of the products of the ion valence and the molar concentration of each element of the 1B group and the 2B group) is M or less (NM ≦ M).

As the additive metal element other than Mg to the Mg—O type insulating layer 2, it is difficult to destroy the NaCl type crystal structure of MgO, and even if the diffusion to the magnetic layer 1 occurs, the magnetic characteristics of the magnetic layer 1 change little. At least selected from Fe and Co in that
It is particularly preferable to use one kind. Since a soft magnetic film with high spontaneous magnetization is generally Fe-based or Fe-Co-based, Fe or Co is replaced by Mg-O.
When added to the system insulating layer 2, the composition change of the magnetic layer 1 due to diffusion of these additional elements can often be substantially ignored. The fact that the magnetic property damage due to diffusion is small means that the adhesive force can be obtained more easily than Mg alone even in the manufacturing process of the magnetic device, and the ratio of the effect of the heat treatment for enhancing the adhesive force to the magnetic property damage is increased. be able to.

However, the NaCl-type Fe-O phase is a high temperature phase,
The NaCl-type Co-O phase is also an unstable phase. Further, if Fe is contained in a very large amount, it may become antiferromagnetic on the low temperature side. Therefore, from the viewpoint of maintaining a stable crystal structure and avoiding magnetism as the insulating layer 2, it is added to the Mg—O based insulating layer 2.
It is desirable that the total number of moles of Fe and Co does not exceed the number of moles of Mg. Further, it is needless to say that it is desirable that the total of the composition ratios of the additional elements does not exceed the composition ratio of Mg even when the other elements are added for the purpose of strengthening the adhesive force, controlling the stress, improving the film quality, etc. as described above. Yes. The actual addition amount is preferably about 1 to 10 mol%.

The composition of Mg and O in the Mg—O type insulating layer 2 itself has a ratio of the number of moles of Mg to the number of moles of O in the insulating layer 2 from the viewpoint of securing a stable MgO crystal structure and preventing diffusion. It is desirable to be close to 1, specifically, 0.9 ≤ (number of moles of Mg) /
It is preferable that (the number of moles of O) ≦ 1.1.

The above-mentioned magnetic layer 1 and Mg-O type insulating layer 2
Is produced by various thin film forming methods such as a sputtering method, a vacuum vapor deposition method, an MBE method, an ion plating method, a laser deposition method and a CVD method. The thickness of the magnetic layer 1 is not particularly limited, but it is preferably 5 μm or less from the viewpoint of reduction of eddy current loss, and the required total magnetic flux is determined by practical laminated film thickness and number of laminated layers. From the viewpoint of realizing it, the thickness is preferably 0.5 μm or more. An excessive increase in the laminated thickness and the number of laminated layers makes it difficult to optimize the magnetic circuit design of the thin film magnetic element, and also complicates the manufacturing process and raises the cost.

The thickness of the Mg-O insulating layer 2 is preferably 50 nm or more in consideration of use as an interlayer insulating layer. Even if the thickness of the interlayer insulating layer is thin, some improvement effect of high frequency characteristics can be obtained, but in order to obtain practical characteristics as a thin film inductor, it is necessary to use a thin film inductor with an excitation frequency of 50 nm or more and 3 MHz or more Is preferably 100 nm or more. Considering mainly the eddy current loss, the thicker the Mg-O insulating layer 2 is, the better it is. However, considering the optimization of the magnetic path as the magnetic element and the total thickness of the required magnetic film, it is appropriate. It goes without saying that there are regions of different values depending on the design of each magnetic element. When a highly spontaneously magnetized metal film is assumed as the planar magnetic element, the thickness of each layer of the magnetic layer 1 is about 0.5 μm to 5 μm, so the Mg-O based insulating layer 2 formed as the interlayer insulating layer In most cases, the optimum thickness is 0.1 μm to 1 μm.

By the way, the conventional soft magnetic film generally has a low magnetization, and in order to increase the spontaneous magnetization in the future, the Fe system or the Fe system is used.
It is necessary to shift to a rich Fe-Co system, and high magnetostriction cannot be avoided. Even in these laminated soft magnetic films having high spontaneous magnetization and high magnetostriction, the use of the Mg—O based insulating layer 2 as an interlayer insulating layer is a means for achieving good magnetic characteristics.

A uniform in-plane uniaxial magnetic anisotropy is imparted to the above-mentioned laminated magnetic film by the following method. Generally, heat treatment in a magnetic field is suitable, but the time and method for imparting uniaxial magnetic anisotropy are not particularly limited. As described above, film formation in the magnetic field of the magnetic layer during lamination,
Magnetic field heat treatment immediately after magnetic film formation, magnetic field heat treatment after magnetic element fabrication, etc. may be applied, or mechanical shape such as substrate shape before lamination, stress introduction before and after lamination, patterning by various etching after lamination, etc. It is also possible to apply the method.
As the heat treatment in a magnetic field, heat treatment in a gradient magnetic field or heat treatment in a vertical magnetic field is also suitable. As a result, it becomes possible to perform hard axis excitation suitable for high frequency excitation. Further, by adopting the above-mentioned Mg-O insulating layer 2, deterioration of magnetic characteristics does not practically occur even in the process of easily causing diffusion such as heat treatment.

As described above, by using the Mg—O type insulating layer 2 as the interlayer insulating layer of the laminated magnetic film, etc., the uniaxial magnetic anisotropy has a practically sufficient etching property and is excellent in controllability. It is possible to obtain a laminated magnetic film including the magnetic layer 1 having the above, that is, a laminated magnetic film having high frequency low loss, high saturation magnetization, and soft magnetism. Furthermore, by using such a laminated magnetic film as a soft magnetic material for a flat magnetic element such as a thin film inductor, it is possible to provide a soft magnetic material having optimum magnetic characteristics required for various flat magnetic elements. A planar magnetic element having excellent electromagnetic characteristics can be realized. The planar magnetic element of the present invention is not limited to thin film inductors and thin film transformers, but can be applied to thin film magnetic heads. As described above, at least the insulating layer 2 containing Mg and O as main components is
A laminated magnetic film which is a material suitable for an interlayer insulating layer of the thinned magnetic layer 1 or the like, and the insulating layer 2 which is in contact with the magnetic layer 1 having in-plane uniaxial magnetic anisotropy and laminated is Saturation magnetization,
Wet etching is possible while having low loss and imparting and controlling in-plane uniaxial magnetic anisotropy. As a result, a highly saturated soft magnetic film that has excellent controllability and fully utilizes the characteristics of magnetic materials, and an optimally designed planar magnetic element (thin film magnetic film that maximizes the ability of a magnetic substance by using the magnetic film). Element) can be provided.

[0035]

Next, specific examples of the present invention will be described.

Examples 1 to 6 and Comparative Examples 1 to 4 Various insulating layers were formed under the conditions shown in Table 1. Further, various magnetic layers were formed under the conditions shown in Table 2. The physical properties of each layer as a single unit are the values evaluated by forming each layer as a single unit using a Si wafer with a thermal oxide film as a substrate.

By using these various magnetic layers and insulating layers,
The laminated magnetic films of the combinations shown in Table 3 were produced. Immediately before forming both the magnetic layer and the insulating layer, the underlying substrate is Ar
It was cleaned by dry etching with gas. In addition, after stacking the layers, a heat treatment in a DC magnetic field (applied DC magnetic field: 128 kA / m, heat treatment temperature: 596 K, heat treatment time: 10800 sec) was applied to each sample in a vacuum atmosphere. The heat treatment magnetic field was applied parallel to the film surface. The sample shape is 10 mm × 10 mm
It is.

For each of the obtained laminated magnetic films, the high frequency magnetic permeability was measured by the inductance method and the magnetization curve was measured by the vibrating sample magnetometer.

[0039]

[Table 1]

[Table 2]

[Table 3] First, the magnetization curve of the laminated magnetic film according to Example 1 is shown in FIG. FIG. 5 is an enlarged view of the magnetization curve in the hard axis direction. The spontaneous magnetization I _s of the magnetic layer was 1.58T. Thus, the spontaneous magnetization was preserved by the heat treatment. In addition, a hard-axis coercive force of 5.3 A / m and an anisotropic magnetic field of 200 A / m, which are important for high-frequency excitation, were obtained.

Further, the high frequency magnetic permeability of Example 1 is shown in FIG. Since it is difficult to accurately calibrate the high-frequency permeability, the measured value may have a factor of 1/2 to 2 with respect to the true value. However, the tan δ which is the ratio of the real part μ _real and the imaginary part μ _imag of the high frequency permeability and the Q value which is the reciprocal of tan δ do not depend on the factor. As shown in FIG. 6, excellent high frequency characteristics having a flat real part were obtained. Also,
The Q value was 24.9 at 5MHz and 14.1 at 10MHz.
A Q value of 10 or more is practically desirable.

It was confirmed that Example 1 disappeared from the substrate by etching using nitric acid, hydrochloric acid, and a mixed acid of nitric acid, hydrochloric acid and phosphoric acid. For example, nitric acid 1,
When the acid solution mixed with pure water at a ratio of 9 was kept at room temperature and steered, and the laminated magnetic film of Example 1 was immersed, it disappeared within 1 minute. It was confirmed that the same etching was performed on Examples 2, 3, 4, 5, and 6.

On the other hand, the laminated magnetic film of Comparative Example 4 using the SiO ₂ layer as the insulating layer did not disappear from the substrate. This shows that excellent workability (wet etching property) is not obtained when SiO ₂ is used as the interlayer insulating layer, and excellent workability is obtained with the insulating layer according to the present invention.

It was also confirmed that the spontaneous magnetization of each of the laminated magnetic films of Examples 2 and 3 did not change within the range of measurement accuracy even after the heat treatment. The hard axis coercive force of Example 2 is 10 A / m,
The Q value at 10 MHz was 42. The hard axis coercive force of Example 3 was 70 A / m, and the Q value at 10 MHz was 11. This is true even if the magnetic layers, which are the constituent elements of the laminated magnetic film of the present invention, have different crystal structures such as amorphous and crystalline, or a combination of different magnetic layer elements. It shows that the invention is effective.

The change in spontaneous magnetization of the laminated magnetic films of Examples 4, 5 and 6 after heat treatment was 1% or less when the spontaneous magnetization before heat treatment was 100%. Regarding the hard axis coercive force and the anisotropic magnetic field, when the value of Example 1 was set to 100%, the value coincided with the value of Example 1 within 3%. These are considered to be equivalent to the case where they do not change practically. Also, 12
When each of the laminated magnetic films of Examples 4 and 5 formed on a Si wafer having a diameter of 7 mm was divided into 5 mm squares using a dicer, no peeling was observed at the interface between the magnetic layer and the interlayer insulating layer. The interlayer insulating layers in the present invention are Mg and O
In addition, it is shown that a good laminated magnetic film can be obtained when Fe and Co are included.

Next, FIG. 7 shows high frequency characteristics of magnetic permeability of the laminated magnetic film of Example 6. In this way, the thickness of the interlayer insulating layer
With the laminated magnetic film of Example 6 having a thickness of 50 nm or less, although good magnetic characteristics were obtained, the Q value was 25.0 at 2 MHz and 8.8 at 5 MHz.
Which is inferior to that of Example 1 shown in FIG. Excitation at about 2 MHz is the practical limit for an interlayer insulating layer having a thickness of about Example 6, and as to Example 1 regarding high performance at a frequency of about 2 MHz or use at 2 MHz or more, It can be seen that it is preferable to use a thicker interlayer insulating layer.

On the other hand, in Comparative Example 1, the hard axis coercive force after heat treatment deteriorated to 200 A / m or more. This value shows that in Comparative Example 1, sufficient soft magnetism cannot be obtained. This indicates that the characteristics of the magnetic layer are deteriorated by the heat treatment when the interlayer insulating layer contains excessive oxygen.

The hard axis coercive forces after heat treatment in Comparative Examples 2 and 3 were 79 A / m and 230 A / m, respectively. These deteriorate the excellent soft magnetism inherent in the magnetic layer. Regarding the anisotropic magnetic field, both Comparative Example 2 and Comparative Example 3 exhibited values of 300 to 400 A / m, and it was found that magnetic anisotropy control using the original characteristics of the magnetic layer becomes impossible. .

As shown in the above Examples and Comparative Examples, the laminated magnetic films according to the Examples of the present invention have practically sufficient etching properties, uniaxial magnetic anisotropy, and high frequency low. It was confirmed that it has excellent loss, high saturation magnetization, and soft magnetism. In addition, it was confirmed that in the comparative example, the magnetic characteristics changed depending on the type of the interlayer insulating layer, and in the comparative example, a sufficient laminated magnetic film could not be obtained.

Embodiment 7 Next, an embodiment of the flat magnetic element of the present invention will be described. Using the magnetic layer 1 and the insulating layer (thickness changed to 0.35 μm / insulating layer 9) used in the above-described Example 1, the lower soft magnetic film 12 and the upper soft magnetic film 12 of the thin film inductor 11 shown in FIG. 8 are used. The magnetic film 13 was produced. Here, the thin film inductor 11 shown in FIG. 8 is configured by laminating a lower soft magnetic film 12 and an upper soft magnetic film 13 on both main surfaces of a double spiral type planar coil 14, and is a planar type. An insulating layer 15 is provided between the coil 14 and the soft magnetic films 12 and 13, respectively.
Is insulated by.

A specific manufacturing example of the thin film inductor 11 will be described below. First, the lower soft magnetic film 12 was formed on a Si (100) wafer. The lower soft magnetic film 12 was formed by repeatedly stacking the insulating layer (9) and the magnetic layer (1) in order. The specific configuration of the lower soft magnetic film 12 is Si
(100) wafer / insulating layer 9 / magnetic layer 1 / insulating layer 9 / magnetic layer 1 / insulating layer 9 / magnetic layer 1 / insulating layer 9 / magnetic layer 1 / insulating layer 9. Next, the planar coil 14 was formed on the lower soft magnetic film 12 by Cu plating. The base electrode for plating was formed by sputtering. Further, the insulating layer 15 was formed by using a polyimide resin and SiO ₂ by a spin coater and sputtering, respectively. The patterning of the planar coil 14 and the insulating layer 15 was performed by transferring a mask corresponding to the pattern by a photoetching process and performing wet etching with an acid solution as in Examples 1 to 6. After this,
The upper soft magnetic film 13 was formed by repeatedly stacking the insulating layer (9) and the magnetic layer (1) on the insulating layer 15 in order. The specific configuration of the lower soft magnetic film 12 is as follows: Si (100) wafer / insulating layer 9 / magnetic layer 1 / insulating layer 9 / magnetic layer 1 / insulating layer 9
/ Magnetic layer 1 / insulating layer 9 / magnetic layer 1 / insulating layer 9

As shown in FIG. 8C, the lower soft magnetic film 12 and the upper soft magnetic film 13 were stacked from the viewpoint of suppressing the eddy current and then subjected to in-plane division. Reference numeral 16 in FIG. 8C is a dividing line. The division of the lower soft magnetic film 12 and the upper soft magnetic film 13 within one element and the separation of each element were also carried out by wet etching using an acid solution, similarly to the patterning of the planar coil 14 and the like. .

FIG. 9 shows the frequency characteristics of the inductance L and the quality factor Q of the thin film inductor 11 thus obtained. As is clear from FIG. 9, a substantially flat inductance was obtained up to 10 MHz, and a quality factor Q of about 15 was obtained near 3 MHz, confirming that the thin film inductor has good characteristics.

In the seventh embodiment, an example in which the planar magnetic element of the present invention is applied to a thin film inductor has been described, but the present invention is not limited to this and can be applied to a thin film transformer, a thin film magnetic head, or the like. Is.

[0054]

As described in detail above, according to the present invention, a laminated magnetic film having high saturation magnetization, low loss, and imparting / controlling in-plane uniaxial magnetic anisotropy and capable of wet etching. Can be provided. Further, according to the planar magnetic element of the present invention using such a laminated magnetic film,
After achieving high performance, mass production becomes easy.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a laminated magnetic film of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the laminated magnetic film of the present invention.

FIG. 3 is a cross-sectional view showing a modified example of the laminated magnetic film shown in FIG.

FIG. 4 is a diagram showing a magnetization curve of a laminated magnetic film according to Example 1 of the present invention.

FIG. 5 is an enlarged view of a magnetization curve in the hard axis direction shown in FIG.

FIG. 6 is a diagram showing a high frequency magnetic permeability of Example 1 of the laminated magnetic film according to Example 1 of the present invention.

FIG. 7 is a diagram showing a high frequency magnetic permeability of Example 1 of a laminated magnetic film according to Example 6 of the present invention.

FIG. 8 is a diagram showing a thin film inductor manufactured in Example 7 of the present invention.

9 is a diagram showing frequency characteristics of an inductance L and a quality factor Q of the thin film inductor shown in FIG.

[Explanation of symbols]

 1 ... Magnetic layer 2 ... Mg-O insulating layer 11 ... Thin film inductor 12, 13 ... Soft magnetic film consisting of laminated magnetic film 14 ... Planar coil

Claims (7)

[Claims] 1. A laminate comprising: a magnetic layer having in-plane uniaxial magnetic anisotropy; and an insulating layer mainly composed of Mg and O arranged in contact with the magnetic layer. Magnetic film. 2. A magnetic layer containing Fe, Co, B and 4B group elements as main constituent elements, and an insulating layer mainly composed of Mg and O, which is laminated in contact with the magnetic layer. A laminated magnetic film characterized in that. 3. The laminated magnetic film according to claim 1, wherein the insulating layer containing Mg and O as main components has a molar ratio of Mg and O of 0.9 ≦ (mol number of Mg) / (O The laminated magnetic film is characterized in that: 4. The laminated magnetic film according to claim 1 or 2, wherein the insulating layer containing Mg and O as main components is at least selected from a metal element other than Mg and a non-metal element other than O.
It contains one kind of additional element, and the sum of the composition ratios of the additional elements is less than the composition ratio of Mg, and the absolute value and molar concentration of the ionic valence of each element of the non-metal elements including O. The laminated magnetic film is characterized in that the sum of the products of the above is less than or equal to the sum of the products of the ion valence and the molar concentration of each element of the metallic elements containing Mg. 5. The laminated magnetic film according to claim 4, wherein the insulating layer containing Mg and O as main components contains at least one additive element selected from Fe and Co. Magnetic film. 6. The laminated magnetic film according to claim 1, wherein the magnetic layer has a thickness in the range of 0.5 to 5 μm, and
The thickness of the insulating layer containing Mg and O as the main components is 50 to 1000.
A laminated magnetic film having a range of nm. 7. A planar magnetic element comprising the laminated magnetic film according to claim 1 or 2 as a constituent element.