JP2007012957A - Coil component and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a Q value of a coil component to be used for various electronic equipment such as a cellular phone. <P>SOLUTION: In order to achieve this purpose, this component is provided with a columnar supporter 3, a coil provided on the surface of an intermediate portion 3B of this supporter 3, and electrodes 6 provided on the surfaces of both ends 3A of the supporter 3. The coil component is formed so that the conductivity of the electrode 6 is lower than that of the coil 5A. This component has an effect of suppressing an eddy current to improve the Q value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coil component used in various electronic devices such as a mobile phone.

  Conventionally, this type of coil component is formed on a support 1 made of ceramic as shown in FIG. 7 ((a) is a top view, (b) is a side view, (c) is a bottom view), and FIG. a) is a top view, (b) is a side view, and (c) is a bottom view), a metal film 2 is formed over the entire surface, and then FIG. 9 ((a) is a top view and (b) is a side view). As shown in the figure, (c) is a bottom view), the coil 2A was formed by cutting the metal film 2 formed on the central portion 1A into a spiral shape.

As prior art document information relating to this application, for example, Patent Document 1 is known.
JP-A-10-270252

  Such a conventional coil component has a problem that the Q value is low.

  That is, when a current is passed through the coil component having the above-described conventional configuration, a large eddy current is generated in the metal film 2 formed on both ends 1A of the support 1, and the magnetic field generated by the coil 2A is interrupted. The value was getting worse.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the Q value in such a coil component.

  In order to achieve this object, the present invention includes a columnar support, a coil provided on the middle surface of the support, and electrodes provided on both end surfaces of the support. The coil component has a rate lower than the conductivity of the coil.

  The coil component of the present invention has an effect of suppressing the eddy current and improving the Q value because the conductivity of the electrode causing the eddy current is lower than that of the coil.

  Further, since the coil has a high conductivity, the Q value can be increased.

(Embodiment 1)
Hereinafter, the coil component in Embodiment 1 of this invention is demonstrated, referring drawings.

  First, as shown in FIG. 1 ((a) is a top view, (b) is a side view, and (c) is a bottom view), a columnar support having both end portions 3A and a middle portion 3B narrower than both end portions 3A. 3 is formed. Both end portions 3A and middle portion 3B may have the same thickness, but it is advantageous to make middle portion 3B thinner when mounted on a P plate or the like.

  As a method for forming the support 3, for example, it can be formed by granulating ceramic powder into particles of about 20 to 30 μm, placing them in a mold and firing them.

  The support 3 may be either a non-magnetic material or a magnetic material, but when a high Q is required in a high frequency band (GHz band), the magnetic material that cannot follow the frequency is lost. Therefore, it is desirable to use a non-magnetic material unrelated to the frequency, and when high Q characteristics, L characteristics, etc. are required in a not so high frequency band (MHz band), the magnetic content of the support 3 is also used. Therefore, it is desirable to use a magnetic material.

  Nonmagnetic materials include inorganic insulating materials such as organic insulating materials such as epoxy and polyimide, various glass materials, glass ceramics mixed with glass and ceramics, ceramics such as CuZn ferrite and alumina. Although there are insulating materials, there is an advantage that the weight can be reduced if an organic insulating material is used, and the use of a ceramic system has an effect that it is resistant to a thermal process.

  As magnetic materials, ferrite materials such as NiZn-based, NiZnCu-based, and MnZn-based spinel-based materials and hexagonal-based materials, and metal-based materials such as Fe-based materials, Co-based materials, sendust, and permalloy can be used. Using a NiZnCu system or a NiZnCu system is preferable because of its merit of high insulation.

  Here, by using the support 3 having a low dielectric constant, the stray capacitance between the coils can be reduced, the self-resonance frequency of the coil can be increased, and the high-frequency characteristics of the coil can be improved. become. Conversely, when a material having a high dielectric constant is used, coil components having various electrical characteristics can be obtained by appropriately adjusting the stray capacitance and the resonance frequency of the coil. That is, the frequency band in which the impedance increases can be adjusted by changing the L value or the dielectric constant of the support 3. Further, by adjusting the stray capacitance, it is possible to ensure the electrical characteristics of a composite part in terms of an equivalent circuit.

  Next, as shown in FIG. 2 ((a) is a top view, (b) is a side view, and (c) is a bottom view), a metal film 4 is formed on the surface of the middle part 3B of the support 3 in FIG. .

  The metal film 4 is formed by applying a copper, copper alloy, silver, silver-palladium alloy, silver-platinum alloy, or a metal paste having a high electrical conductivity such as platinum and baking it. . In particular, pure silver and pure copper are desirable because of their high conductivity. In addition, it is desirable that the firing in the case of using an easily oxidizable metal such as copper or copper alloy is performed in a nitrogen atmosphere and the metal film 4 is not oxidized.

  Here, since the metal film 4 is formed by applying and baking a paste, it necessarily includes voids and glass frit. In this way, the conductivity of the metal film 4 is intentionally lowered.

  Thereafter, as shown in FIG. 3 ((a) is a top view, (b) is a side view, and (c) is a bottom view), the metal film 5 is formed by electroplating using the metal film 4 in FIG. 2 as an electrode for plating. Form. The metal film 5 has high conductivity because it does not have voids or pieces of glass frit that the metal film 4 has. If the metal film 5 is sufficiently thicker than the metal film 4, the conductivity of the coil (shown in a later step) can be increased and the Q value can be increased.

  Next, as shown in FIG. 4 ((a) is a top view, (b) is a side view, and (c) is a bottom view), electrodes 6 are formed on both end portions 3A of the support 3. At this time, even if the metal of the same element as that of the metal film 5 is used for the electrode 6, the conductivity of the electrode 6 is lower than the conductivity of the metal film 5 because of the gap and the glass frit. The Q value is not lowered without hindering the magnetic flux generated in the subsequent process). Here, when the electrode 6 and the metal film 4 are made of the same element, there is an advantage that an alloy is not formed in the coil (shown in a later step). If an alloy is formed, there is a problem that the electrical conductivity is lowered and a problem that the heat resistance is poor because the melting point is lowered, and an accurate coil shape cannot be maintained. Therefore, when composed of the same element, these problems can be avoided. On the other hand, when a material having a higher resistance than that of the metal film 4 is used, the amount of eddy current generated on both ends 3A can be further reduced, and the magnetic flux generated in the coil (shown in a later process) is not hindered. This has the effect of not lowering the Q value.

  Further, by forming this electrode 6 not only on the whole end portions 3A but on the connection portion with the extraction electrode (shown in a later step) and only on the mounting portion on the P plate (not shown), an eddy current Can be further reduced.

  Here, the electrode 6 is formed of a paste. In general, when paste is used, voids and fragments of glass frit remain, so the resistance is higher than when plating using the same type of material, and eddy currents are less likely to occur, so the Q value can be improved. I have to. Furthermore, when a paste is used, it has the effect that the adhesiveness of the support body 3 and the electrode 6 can be improved compared with the plating method.

  In addition, the resistance can be further increased by reducing the thickness of the electrode 6.

  Next, as shown in FIG. 5 ((a) is a top view, (b) is a side view, and (c) is a bottom view), two layers comprising a metal film 4 in FIG. 2 and a metal film 5 in FIG. From this, a spiral coil 5A and lead electrodes 5B at both ends thereof are formed. As a formation method, there are a method in which a resist is applied to the entire surface, and ultraviolet rays are irradiated in a spiral shape, followed by etching by immersion in an alkaline solution, and a method of cutting by laser irradiation, but a method of forming using a YAG laser is available. In order to enable fine processing, the number of turns of the coil 5A can be increased, and a large L value can be obtained.

  Further, after the two layers of the metal film 4 in FIG. 2 and the metal film 5 in FIG. 4 are patterned into the spiral coil 5A and the extraction electrode 5B, the coil 5A, the extraction electrode 5B, and the like are etched to form burrs and the like. By smoothing the electrode surface, the insulating layer (shown in a later process) need not be covered with an insulating layer (shown in a later process), so that the insulating layer (shown in a later process) can be made thin. Yes. In particular, when the coil 5 </ b> A is formed by laser irradiation, this effect becomes significant because burrs increase.

  Further, by removing the metal adhering to the surface of the support 3, generation of eddy current can be prevented, and the Q value can be improved without disturbing the magnetic flux of the coil 5 </ b> A. In particular, when the coil 5A is formed by laser irradiation, this effect becomes significant because there are many scattered objects.

  Then, as shown in FIG. 6 ((a) is a top view, (b) is a side view, and (c) is a bottom view), the surface of the coil 5A and the extraction electrode 5B formed in the middle part 3B in FIG. By covering with 7, the coil 5 </ b> A and the extraction electrode 5 </ b> B can be insulated. By doing so, other components are not affected during mounting, so that high-density mounting is possible. In addition, stabilization of characteristics, protection of the coil 5A, and the like are possible. Further, even when a nickel layer (not shown) and a tin layer (not shown) are formed on the electrode 6, the nickel layer (not shown) and the tin layer (not shown) are attached to the coil 5A. There is an effect that there is no worry.

  With such a configuration, the electrode 6 is formed by applying paste and baking, and by including voids and glass frit, the eddy current can be reduced and the Q value can be improved by increasing the resistance.

  On the other hand, the metal film 5 constituting the coil 5A is formed by electroplating, so that the Q value can be improved by obtaining high conductivity without including voids and glass frit.

  Furthermore, the Q value can be further improved by forming the electrode 6 only at the connection portion with the extraction electrode 5B, not the entire end portions 3A.

  Furthermore, by forming the electrode 6 thin, the eddy current can be further reduced and the Q value can be improved.

  Furthermore, since the metal film 4 has a lower conductivity than the metal film 5, by setting the thickness of the metal film 5 to be greater than the thickness of the metal film 4, the overall resistance of the coil 5 </ b> A is lowered, and the Q value is further increased. Can be improved.

  The coil component of the present invention has the effect of suppressing the eddy current and improving the Q value by keeping the conductivity of the electrode lower than the conductivity of the coil. Useful.

(A) Top view of coil component in one manufacturing process according to Embodiment 1 of the present invention, (b) Side view, (c) Bottom view (A) Top view of coil component in one manufacturing process according to Embodiment 1 of the present invention, (b) Side view, (c) Bottom view (A) Top view of coil component in one manufacturing process according to Embodiment 1 of the present invention, (b) Side view, (c) Bottom view (A) Top view of coil component in one manufacturing process according to Embodiment 1 of the present invention, (b) Side view, (c) Bottom view (A) Top view of coil component in one manufacturing process according to Embodiment 1 of the present invention, (b) Side view, (c) Bottom view (A) Top view of coil component in one manufacturing process according to Embodiment 1 of the present invention, (b) Side view, (c) Bottom view (A) Top view of one manufacturing process in a conventional coil component, (b) Side view, (c) Bottom view (A) Top view of one manufacturing process in a conventional coil component, (b) Side view, (c) Bottom view (A) Top view of one manufacturing process in a conventional coil component, (b) Side view, (c) Bottom view

Explanation of symbols

3 Support 3A Both Ends 3B Middle 5A Coil 5B Lead Electrode 6 Electrode

Claims (12)

A coil component comprising a columnar support, a coil provided on the middle surface of the support, and electrodes provided on both end surfaces of the support, the conductivity of which is lower than the conductivity of the coil . The coil component according to claim 1, wherein the electrode has a gap. The coil component according to claim 1, wherein the coil has a lower layer and an upper layer, and a metal constituting the lower layer and a metal constituting the upper layer are the same element. The coil component according to claim 1, wherein the coil has a lower layer and an upper layer, and the conductivity of the upper layer is higher than the conductivity of the lower layer. The coil component according to claim 4, wherein the upper layer of the coil is thicker than the lower layer. The coil component according to claim 4, wherein a gap is formed in a lower layer of the coil. A columnar support is formed, then a paste-like first metal film is applied to the middle surface of the support and fired, and then a second metal film is formed on the surface of the first metal film by electroplating. And then baking a paste-like third metal film on both end surfaces of the support, and then forming the first metal film and the second metal film into a spiral shape Manufacturing method. The method for manufacturing a coil component according to claim 7, wherein the first metal film, the second metal film, and the third metal film are the same element. The method for manufacturing a coil component according to claim 7, wherein the conductivity of the third metal film is lower than the conductivity of the second metal film. The method for manufacturing a coil component according to claim 7, wherein the conductivity of the first metal film is lower than the conductivity of the second metal film. The method for manufacturing a coil component according to claim 7, wherein the first metal film is thinner than the second metal film. The method for manufacturing a coil component according to claim 7, wherein the third metal film is formed thinner than the second metal film.

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