JP2958806B2 - Electronic components for surface mounting - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount electronic component used for an electronic circuit, and more particularly to a multilayer transformer and an in-phase inductor used for a high frequency circuit and used for a surface mount. The present invention relates to an electronic component for surface mounting.

[Prior Art] Conventionally, a surface mount type electronic component as shown in a perspective view of FIG. 7 has been used. FIG. 8 is a sectional view of the electronic component for surface mounting of FIG.

In FIG. 8, the surface-mounted electronic component 70 has at least two linear or meandering conductors 82 and 83 formed in the ferrite magnetic layer 14 so that the ends are exposed.

The magnetic layer 84 is obtained by forming, drying and laminating a ferrite paste containing ferrite magnetic fine powder and an organic binder as main raw materials and an organic solvent as a dispersion medium. On the other hand, the conductors 82 and 83 are obtained from a conductive paste containing metal fine powder and an organic binder as main raw materials and an organic solvent as a dispersion medium inside the magnetic layer.

In conventional surface mount electronic components, a ferrite paste is formed, dried and superimposed and laminated, and at least two or more linear or meandering conductors are sandwiched from the conductive paste to form a film and dried. After being molded, it was sintered integrally, and the end of the sintered body was provided with the conductor portion as shown in FIG.
Membrane electrode terminals 71A, 71B, 72 connected to 82, 83, respectively
A / 72B is provided.

This electronic component for surface mounting has a dispersive property such that the specular gloss (incident angle 60 ° -reflection angle 60 °) of the surface is 30% or less when the film is dried as a ferrite paste for forming the magnetic layer 14. In general, it was often done to compose the whole.

On the other hand, there is an electronic component for surface mounting composed of a ferrite laminate with a high filling and high density of the magnetic layer 84. Even in this case, the ferrite paste has a specular gloss (incident angle of 60 °) on the surface when the film is dried. -The reflection angle of 60%) is generally 40% or more, and it is common practice to constitute the whole.

Further, in the conventional electronic device for surface mounting shown in FIG. 8, a non-magnetic material may be used between the conductors 82 and 83 or the like. Ninth
The figure shows the laminate 90 when a non-magnetic layer is formed between conductors. In FIG. 9, the non-magnetic layer has a specular gloss (incident angle) on the surface of the non-magnetic paste when the non-magnetic paste is dried.
(60 ° -reflection angle 60 °) is 30% or less.

The surface mount electronic components shown in FIGS. 7, 8 and 9 have a specular glossiness (incident angle 60 ° −reflection angle 60 °) of 30% or less even when the conductive paste is formed and dried. The whole was composed of those having a dispersibility of the degree of

[Problems to be Solved by the Invention] However, in order to further improve the performance and reliability of the above-mentioned surface mount electronic component and to further improve the characteristics as a device, the above-described configuration requires the paste dispersibility and the laminated body. It has been found that there are various disadvantages in terms of the filling property and the density of the sintered body. In other words, in order to achieve higher performance and higher reliability, it is necessary to improve the paste dispersibility, increase the packing ratio of the laminated body, and furthermore, bring the sintered body density as close as possible to the theoretical density. In the conventional technology, the ferrite paste has a dispersive property such that the specular gloss (incident angle 60 ° -reflection angle 60 °) of the surface during film drying is less than 30%, so the filling rate of the laminate is low. The sintering density is about 90% of the theoretical density. When used as a surface-mounting electronic component in a severe environment such as high temperature and high humidity, the short circuit between the conductors 12 and 13 due to the penetration of moisture etc. In addition, the conductor may be damaged or the insulation between the conductor phases may be deteriorated due to migration or corrosion. In the worst case, the conductor may be disconnected or short-circuited, and the reliability or function of the laminated transformer may be lost. There has been a drawback that.

In addition, in conventional surface mount electronic components, the dispersibility during paste is insufficient, so that uniform filling of particles cannot be obtained and uniform grain growth can be obtained even when densification is performed at a predetermined sintering temperature. The ferrite grain growth itself tends to be insufficient.

In the case where the entire surface-mounting electronic component is formed with high filling and high density, the ferrite paste becomes a mirror gloss (incident angle 60 ° −reflection angle 60 °) of the surface when the film is dried.
In this case, cracks occur at the time of sheet forming, and the flexibility of the sheet itself is lost. From the viewpoint of cost, the ferrite paste has a high-dispersion ferrite paste of 40% or more as a whole, compared with a mirror gloss (incident angle 60 ° -reflection angle 60 °) of 30% or less when the film is dried. There was a disadvantage that use was industrially disadvantageous.

Also, in terms of characteristics, if the whole is made of magnetic ferrite, a minor loop is generated between the mutual conductors, and the coupling coefficient is reduced.
It was about 0.7 at most, and the characteristics as a common-mode inductor or transformer were insufficient.

Further, the conductor using the conductive paste has a drawback that, similarly to the ferrite paste, the filling is insufficient and the DC resistance after sintering is higher than the theoretical value.

Accordingly, a technical problem of the present invention is to provide a surface-mounted electronic component such as a laminated transformer and an in-phase inductor having high performance and high reliability even in a severe environment by eliminating the drawbacks of the conventional technology. It is in.

[Means for Solving the Problems] According to the present invention, a plurality of linear conductors are opposed to each other via a nonmagnetic layer, sandwiched between magnetic layers, and at least one end of each conductor is connected to the conductor. In the surface-mounted electronic component exposed at the end face of the magnetic layer, at least the non-magnetic layer between the plurality of conductor portions has a mirror gloss of the surface during film formation and drying.
According to the present invention, there is provided an electronic component for surface mounting, wherein the electronic component for surface mounting is formed of a non-magnetic paste showing 40%.
The conductor part is buried in the non-magnetic layer to obtain an electronic component for surface mounting.

According to the present invention, in any of the above surface-mount electronic components, the conductor portion is formed of a conductive paste having a mirror gloss of 40% or more on the surface when the film is dried. Is obtained.

Here, in the present invention, the non-magnetic layer, particularly by using non-magnetic zinc ferrite, can sufficiently prevent delamination and the like generated during the three-material sintering and sufficiently improve the characteristics. It is possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First Embodiment FIG. 1 is a cross-sectional view showing a basic configuration example of a laminated transformer as a surface mounting electronic component according to a first embodiment of the present invention. For the sake of simplicity, it is not a connected shape, it is a diagram of one unit, and a part of the conductor is emphasized.

In FIG. 1, a non-magnetic layer 11 is interposed in a magnetic layer 14,
Meandering or straight conductor portions 22 and 23 are formed facing each other. The magnetic layer 14 is made of a ferrite paste containing ferrite fine powder and an organic binder as main raw materials and an organic solvent as a dispersion medium. The conductor portion 14 is made of a conductive paste using metal fine powder and an organic binder as main raw materials and an organic solvent as a dispersion medium.

Further, as shown in FIG. 5, the nonmagnetic layer 24 between the conductors 11 and 12 has a high specular gloss (incident angle 60 ° -reflection angle 60 °) of the surface during film formation and drying, which is 40% or more. By using a dispersed non-magnetic paste, a high-density, high-density laminate is formed.

The magnetic layer 14 is made of a ferrite laminate made of a ferrite paste whose surface has a specular gloss (incident angle 60 ° -reflection angle 60 °) of 30% or less when the film is dried.

The non-magnetic layer can sufficiently improve the characteristics as a device by using non-magnetic zinc ferrite, and can sufficiently prevent delamination which occurs upon sintering of the three materials.

In addition, the conductive paste is a highly dispersed conductive paste that has a specular gloss (incident angle 60 ° -reflection angle 60 °) of 40% or more when the film is dried.
13, the DC resistance value after sintering can be reduced by about 10 to 30% compared to the one molded using a conventional conductive paste, and the surface roughness during film formation can be reduced. Because it can be reduced considerably, high-precision film formation can be performed.
It is possible to form a film with sufficiently high precision even on a complicated and fine conductor as shown in FIG. 6, and it is possible to provide a high-performance, high-reliability, high-precision and small-sized laminated transformer.

FIG. 6 is an exploded view of the electronic component for surface mounting of FIG. With reference to FIG. 6, a method of manufacturing the electronic component for surface mounting according to the first embodiment of the present invention will be described. A ferrite paste is formed into a sheet shape as a magnetic layer 14 and dried to form a magnetic sheet 61, a conductive paste is formed as a conductor 13 thereon, dried and laminated, and a nonmagnetic paste is formed as a nonmagnetic layer 11. Films are dried and laminated, and then a conductive paste for the conductor portion 12 and a magnetic sheet 61 made of the same ferrite paste as the lower magnetic sheet 61 are sequentially formed on the layers, dried and laminated, and laminated. And sintered integrally with a hot isostatic press or the like. No. 7
As in the conventional example shown in the drawing, the electrode films 71A, 71B, 72A, and 72B are provided to form a surface-mounting electronic component.

With such a configuration, in terms of characteristics, it is possible to sufficiently prevent the penetration of moisture and the like even when used in a harsh environment while sufficiently satisfying the coupling coefficient of 0.9 or more.
In addition to sufficiently preventing damage to the conductors 12 and 13 or deterioration of insulation between the conductors 12 and 13 due to short circuit or migration or corrosion between the conductors and disconnection or short circuit, cracks may occur during sheet molding.
It is possible to sufficiently prevent the drawback that the operability is extremely deteriorated because the flexibility of the sheet itself is lost, and to form a laminated transformer which is very advantageous in terms of the number of steps and cost.

FIG. 2 is a cross-sectional view showing another example of a laminated transformer as an electronic component for surface mounting according to a second embodiment of the present invention. The laminated transformer of this example has the same basic configuration as that of FIG. 4 except that the nonmagnetic layer 21 extends on both sides, and is manufactured by the same method as the laminated transformer of the first embodiment.

FIG. 3 is a diagram showing another configuration example of a multilayer transformer as a surface mounting electronic component according to a third embodiment of the present invention. In FIG. 3, conductor portions 32 and 33 are embedded in the nonmagnetic layer 11 in the magnetic layer 14. The non-magnetic layer between the conductor portions and around the conductor portion is coated with a high-dispersion non-magnetic paste having a specular gloss (incident angle 60 ° -reflection angle 60 °) of 40% or more when the film is dried. High filling by using,
It is composed of a high-density laminate. Furthermore, the mirror gloss (incident angle 60 ° -reflection angle 60 °) of the surface of the high-density, high-density non-magnetic layer between the conductors 32 and 3 and around the conductor when the film is formed and dried is reduced. It is made using ferrite paste that shows less than 30%.

The electronic component for surface mounting according to the third embodiment of the present invention is manufactured as follows.

A ferrite paste is formed into a sheet as a magnetic layer 14 and dried. A nonmagnetic paste is formed as a nonmagnetic layer 11 on the ferrite paste and dried. A conductive paste is formed as a conductor 13 thereon and dried. Then, a non-magnetic paste is deposited as the non-magnetic layer 11, dried, and laminated. A conductive paste, a non-magnetic paste, and a ferrite paste are again deposited as the conductor 12, dried, and laminated. Then, a laminate is formed and integrally formed by hot isostatic pressing or the like. This sintered body was added to the electrode films 71A and 71A in the same manner as in the conventional example shown in FIG.
By providing 1B, 72A, and 72B, it becomes an electronic component for surface mounting.

The electronic component for surface mounting formed in this way can be damaged in conductors or deteriorated insulation between conductor phases due to short-circuiting or migration or corrosion between the conductors even when used in severe environments such as severe high temperature and high humidity. While fully preventing the phenomenon of wire breakage or disconnection, it is possible to form a laminated transformer that has sufficiently improved characteristics and is very advantageous in terms of the number of processes and cost, and has sufficiently eliminated the drawbacks of the conventional technology. Thus, it is possible to provide a surface-mounting electronic component which has improved industrial economical efficiency by preventing it.

FIG. 4 is a cross-sectional view showing still another example of the configuration of a multilayer transformer as a surface mounting electronic component according to a fourth embodiment of the present invention. The basic configuration of the multilayer transformer of this example is the same as that of the multilayer transformer of FIG. 3 except that the nonmagnetic layer 11 extends on both sides, and is the same as that of the electronic component for surface mounting according to the third embodiment. Being manufactured.

As described above, according to the surface-mounting electronic component of the fourth embodiment of the present invention, it is possible to sufficiently prevent the drawbacks of the prior art and sufficiently prevent the penetration of moisture and the like even when used in a severe environment. While sufficiently preventing the phenomenon of conductor damage, deterioration of insulation between conductor phases, disconnection or short-circuit due to short-circuiting, migration or corrosion between the conductors, cracks may occur during sheet molding, and the flexibility of the sheet itself may be reduced. In addition to preventing the drawback that operability becomes extremely poor due to the absence of elimination, a laminated transformer that is very advantageous in terms of the number of steps and cost is formed, and the industrial economics can be sufficiently enhanced to support the high frequency band. It can be said that the industrial benefits of providing a mounting multilayer transformer are extremely large.

In the first to fourth embodiments of the present invention, the specular gloss (incident angle 60 ° -reflection angle 60 °) of the surface during film drying is 30.
% Ferrite paste can be easily manufactured using a high-speed dispersing machine such as a homogenizer or a roll dispersing machine such as a three-roll mill as a general manufacturing method. High-dispersion non-magnetic pastes or conductive pastes whose surface has a specular gloss (incidence angle 60 ° -reflection angle 60 °) of 40% or more, such as a homogenizer as a general manufacturing method such as the ferrite paste described above. Instead of using a high-speed disperser or a roll disperser such as a three-roll disperser, one example of a production method is to use a non-magnetic fine powder and an organic binder as a main raw material and an organic solvent. Is pre-kneaded using a low-rotation and high-shearing stirrer such as a kneader or a planetary mixer, followed by high-speed rotation in a vessel such as a bead mill. Diameter of the beads and the like, can be produced by subjecting a high dispersion with a stirrer was charged with media about 0.1~3mm 60~90vol%.

Further, in the first to fourth embodiments of the present invention, a method of forming a film using a ferrite paste, a non-magnetic paste or the conductive paste includes a printing method, a coating method, a doctor blade method, an extrusion molding method, an injection molding method. The effect of the present invention is not affected by any manufacturing method such as the method.

In the first to fourth embodiments of the present invention, only the multilayer transformer has been described as a surface mounting component. However, it is needless to say that an in-phase inductor can be manufactured with a similar configuration.

[Effects of the Invention] As described above, according to the present invention, the space between the conductors is made of a non-magnetic material instead of the ferrite magnetic material, and the specular gloss of the surface (incident angle 60 ° −reflection angle 60゜) is 40%
By using the high-dispersion non-magnetic paste described above, a highly-filled, high-density non-magnetic laminate is formed. Is composed of a ferrite laminate made of ferrite paste with a specular gloss (incidence angle 60 °-reflection angle 60 °) of 30% or less. Even when used in a severe environment where the resistance is low, the penetration of moisture and the like is sufficiently prevented, and the short-circuit or migration or corrosion between the conductors causes damage to the conductors, deterioration of insulation between the conductor phases, disconnection or short-circuit. It is said that the operability is extremely deteriorated because cracks are generated during sheet formation and the flexibility of the sheet itself is lost while sufficiently preventing While the disadvantages preventing sufficient number of steps,
It is possible to provide an electronic component for laminated surface mounting which is very advantageous also in terms of cost.

Further, according to the present invention, the space between the conductor portions and the periphery of the conductor portion is made of a non-magnetic material, and the surface glossiness (incident angle 60 ° -reflection angle 60 °) of the surface during film drying is 40% or more. By using a highly dispersed non-magnetic paste showing
Due to the high-density non-magnetic laminate, even if used in harsh environments such as severe high temperature and high humidity, the conductors may be damaged or deteriorate due to short-circuiting or migration or corrosion between conductors. And the phenomenon of disconnection or short circuit can be sufficiently prevented.

Furthermore, according to the present invention, the conductive paste has a specular gloss (incidence angle of 60 ° -reflection angle of 60 °) on its surface when the film is dried.
The use of a highly-dispersed conductive paste with an average of 40% or more improves the filling factor of the conductor, and the DC resistance after sintering is 10% higher than that of a product formed using a conventional conductive paste.
It can be reduced by about 30%, and the surface roughness at the time of film formation can be considerably reduced, so that highly accurate film formation can be performed.

As described above, according to the present invention, it is possible to provide a surface-mounting electronic component that has sufficiently improved characteristics as a device, and is very advantageous in terms of high reliability, the number of steps, and cost.

Further, according to the present invention, it is possible to provide an electronic component for surface mounting, which sufficiently prevents the disadvantages of the prior art and improves industrial economy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a surface mounting electronic component according to a first embodiment of the present invention, FIG. 2 is a sectional view showing a surface mounting electronic component according to a second embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view showing a surface mounting electronic component according to a third embodiment of the present invention, FIG. 4 is a cross-sectional view showing a surface mounting electronic component according to a fourth embodiment of the present invention, and FIG. FIG. 6 is a view showing a measuring method, FIG. 6 is an exploded view of the electronic component for surface mounting of FIG. 1, FIG. 7 is a perspective view showing the appearance of the electronic component for surface mounting, and FIG. FIG. 9 is a cross-sectional view of an electronic component for use, and FIG. 9 is a perspective view showing the appearance of a laminate of another electronic component for surface mounting according to another conventional example. In the figure, 11 ... non-magnetic layer, 12/13 ... conductor, 14 ... magnetic layer,
62 · 63 ··· Conductor, 64 ··· Non-magnetic layer, 70 ··· Surface mounting electronic components, 71A / 71B / 72A / 72B ··· External electrodes, 90 ··· Laminated body (sintered body).

Claims (3)

(57) [Claims] 1. A surface mounting method in which a plurality of linear conductors are opposed to each other via a non-magnetic layer, sandwiched between magnetic layers, and at least one end of each conductor is exposed to an end face of the magnetic layer. In the electronic component, at least the non-magnetic layer between the plurality of conductors is formed of a non-magnetic paste having a mirror gloss of at least 40% on the surface when the film is dried. For electronic components. 2. The electronic component for surface mounting according to claim 1, wherein said conductor is buried in said nonmagnetic layer. 3. The electronic component for surface mounting according to claim 1, wherein said conductor portion is formed of a conductive paste having a mirror gloss of 40% or more on the surface when the film is dried. Electronic components for surface mounting.