TW201712162A - Method for manufacturing ceramic electronic component, and ceramic electronic component - Google Patents

Abstract

Proposed are a manufacturing method that is capable of forming an electrode on any part of a surface of a sintered ceramic body in accordance with a simple approach, and a ceramic electronic component manufactured by the method. The method for manufacturing a ceramic electronic component includes steps of preparing a sintered ceramic body 10 containing a metal oxide, irradiating an electrode formation region on a surface of the ceramic body 10 with a laser L to partially lower resistance of the ceramic body 10, thereby forming a low-resistance portion 40, and subjecting the ceramic body to plating to deposit a plated metal 14a serving as an electrode on the low-resistance portion 40, and growing the plated metal to extend over the entire electrode formation region.

Description

Ceramic electronic component manufacturing method and ceramic electronic component

The present invention relates to a method of manufacturing a ceramic electronic component and a ceramic electronic component, and more particularly to the formation of an electrode of a ceramic electronic component.

Conventionally, in the method of forming an external electrode of a ceramic electronic component, an electrode paste is applied to both end faces of the sintered ceramic body, and after plating to form a base electrode, an upper electrode is formed on the base electrode by a plating process. However, in this method, the formation of the base electrode requires a coating step of the paste and a heating step accompanying the plating, and thus there is a problem that the manufacturing step is complicated and the cost is increased.

In addition, when the conductive paste is applied in the formation of the base electrode, there is a problem that the coating shape thereof is restricted. For example, when a conductive paste is formed by dip coating at both end portions of a cubic ceramic body, the conductive paste is applied not only to the both end faces of the ceramic body but also to the four side faces adjacent to the both end faces. Therefore, the finally formed external electrode has a shape that is expanded to both end faces and four side faces adjacent thereto.

In place of such a conventional electrode formation method, a method of forming an external electrode by only plating treatment has been proposed (Patent Document 1). The method exposes a plurality of ends of the internal electrode close to each other at an end face of the ceramic body, and causes a dummy terminal called an anchor tab. The ceramic body is subjected to electroless plating close to the end surface of the end portion of the internal electrode, and the end portion of the internal electrode and the anchor label are used as a core to grow the plating metal to form an external electrode.

However, in this method, it is necessary to expose the end portions of the plurality of internal electrodes to the anchor tag in the external electrode forming portion of the ceramic body, and there is a disadvantage that the manufacturing steps are complicated and the cost is increased. Further, since the surface on which the plating metal is formed is restricted by the end portion of the internal electrode and the surface on which the anchor label is exposed, the external electrode cannot be formed in any portion.

On the other hand, Patent Documents 2, 3, and 4 disclose a method of forming a coil pattern by irradiating a laser and then extruding an electrode after forming an electrode on the entire surface of a ferrite constituting the inductor. At this time, the heat of the laser not only affects the ferrite but also the ferrite on the lower side thereof, and the properties of a part of the ferrite change, thereby making the conductor or the resistance low (refer to paragraph 0005 of Patent Document 2, Patent Literature) Paragraph 0004 of 3, paragraph 0005 of Patent Document 4). However, in these documents, only the irradiation of the laser is disclosed to burn the electrode, and the heat of the laser is described to have a negative influence on the characteristics of the inductor.

[Prior Art Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-40084

Patent Document 2: Japanese Laid-Open Patent Publication No. 2000-223342

Patent Document 3: Japanese Laid-Open Patent Publication No. 2000-243629

Patent Document 4: Japanese Laid-Open Patent Publication No. 11-176685

Accordingly, an object of the present invention is to provide a method for producing an electrode on an arbitrary portion of a surface of a sintered ceramic body by a simple method, and a ceramic electronic component produced by the method.

In order to achieve the above object, the present invention provides a method of manufacturing a ceramic electronic component having the following steps.

A: a step of preparing a sintered ceramic body containing a metal oxide; and B: locally heating the electrode formation region on the surface of the ceramic body to form a low-resistance portion that reduces a part of the ceramic body And a step of depositing a plating metal to be an electrode on the low-resistance portion and growing the plating metal so as to extend over the entire electrode formation region by performing a plating treatment on the ceramic body.

The present invention pays attention to the following aspects: by locally heating the electrode formation region on the surface of the sintered ceramic body to lower the resistance or the conductor of the heating portion, the ceramic body can be made low by plating treatment. The resistor portion serves as a precipitation starting point of the plating metal. The low-resistance portion (or the conductor portion) is a portion that changes the metal oxide material constituting the ceramic body by local heating and has a lower resistance value than the metal oxide. When the locally heated ceramic body is subjected to a plating treatment, the plated metal is first deposited in the low-resistance portion, and the plated metal is rapidly grown by using the deposited plated metal as a core, whereby the electrode covering the entire electrode formation region can be efficiently formed. Therefore, complicated steps such as coating and plating of the conductive paste as in the related art are not required, and the step of forming the electrode can be simplified. Further, it is not necessary to have a plurality of internal electrodes and anchor tags as in Patent Document 1. Since the end surface of the ceramic body is exposed and exposed, there is no restriction on the shape of the electrode, and the manufacturing steps are simplified, and the cost can be reduced.

The low resistance portion may include a reduction layer obtained by reducing a part of the metal oxide contained in the ceramic body. A part of the metal oxide is reduced to conduct or semiconductorize the metal oxide, and the plating metal is easily precipitated. Further, it may be a structure in which a part or all of the surface layer of the reduction layer is covered by the reoxidation layer. In the case where the reoxidation layer is formed, the oxidation of the reduction layer in the lower layer is suppressed, and the effect of suppressing the temporal change of the reoxidation layer itself is obtained. Further, the reoxidation layer is a semiconductor having a lower resistance value than the metal oxide as an insulator, so that the plating metal is easily precipitated on the reoxidation layer. Further, the reoxidation layer is formed into a film shape of, for example, nm order, so that a dielectric ball for electrolytic plating is brought into contact with the reoxidation layer to peel off a part of the reoxidation layer, or the plating solution erodes the reoxidation layer, and is in reoxidation. The possibility of electroplating on the reduction layer under the layer.

The electrode of the present invention is not limited to the external electrode as long as it is an electrode formed on the surface of the ceramic body, and may be any electrode. For example, it may be a spiral electrode or a wiring electrode. As a local heating method, for example, there are various methods such as laser irradiation, electron beam irradiation, or local heating using an image furnace. Among them, laser irradiation is advantageous in terms of rapidly changing the irradiation position of the laser with respect to the ceramic body.

In the present invention, only the electrode formation region is locally heated and subjected to a plating treatment, so that an electrode can be formed in an arbitrary portion. For example, in a method using a conventional conductive paste, a deformed electrode is formed, that is, one end surface adjacent to the both end faces (the side L-shaped) is formed on both end faces to form an external electrode, or is formed on one side surface at intervals It is difficult to form a plurality of external electrodes, and such an external electrode of any shape in the present invention can also be easily formed. The local heating may be only in the surface portion of the ceramic body, and thus does not have a practical influence on the characteristics as a ceramic electronic component such as an inductor.

As a method of the plating treatment, electrolytic plating or electroless plating may be used, but electrolytic plating is preferred. That is, in the electrolytic plating method, conductivity is required as an object to be plated. Since the low-resistance portion formed by the method of the present invention has conductivity, the current density flowing in the low-resistance portion during electrolytic plating is higher than that of the other portions, and the plating metal is rapidly precipitated in the low-resistance portion. In the conventional plating method, when it is not desired to perform plating on a part of the ceramic body, it is necessary to apply a plating resist material to the portion in advance. In the present invention, the plated electrode is rapidly expanded in the electrode formation region by using the low-resistance portion as a core. On the other hand, the portion other than the electrode formation region is insulative and does not become a conductive portion of the core, so that the growth rate of the plating electrode is slow. Therefore, the plating metal can be selectively grown in the electrode formation region without applying the plating preventing material. Further, since the thickness of the plating metal formed on the low-resistance portion by electrolytic plating is thicker than the other portions, there is an advantage that the plating electrode has a high fixing strength with respect to the ceramic body.

The invention can also be applied to electronic components having internal electrodes. For example, the low-resistance portion may be formed on the surface of the cubic ceramic body by the laser irradiation or the like, and the external electrode may be formed to cover the end portion of the internal electrode by a plating treatment. The electrode can be formed on any surface as long as it is a surface that can be locally heated such as laser processing. For example, it is also possible to form electrodes on both side faces in the width direction. In an electronic component in which external electrodes are not formed on both side surfaces in the width direction, when the electronic component is mounted at a high density, the insulation distance between the electronic components adjacent to the width direction can be secured, and the risk of short circuit can be reduced. Therefore, further high-density mounting can be performed. Further, when the external electrode is formed only on the lower surface (bottom surface) of the ceramic body, it is attached only to the bottom surface, so that it can be further reduced Risk of short circuit with surrounding electronic parts.

The present invention can also be applied to, for example, a wound coil component. In other words, the ceramic body may have a flange portion at both end portions and a ferrite core portion having a core portion therebetween, and may be formed by laser processing at the core portion of the ferrite core portion. In the coil-shaped low-resistance portion, a low-resistance portion having an external electrode shape is formed by a laser processing or the like at a flange portion of the core portion, and a coil-shaped low-resistance portion is connected to a low-resistance portion of an external electrode shape, and the coil shape is low. A plating electrode is continuously formed on the low resistance portion of the resistor portion and the shape of the external electrode. In this case, both the coil portion and the external electrode portion can be formed by laser processing or the like, and thus the manufacturing is further simplified. Further, the electrode of the coil portion can be made thicker than the external electrode by a method of adjusting the laser intensity or the like.

In addition, the ceramic body may have a flange portion at both end portions and a ferrite core portion having a winding core portion therebetween, and a lead wire may be wound around the circumferential surface of the winding core portion. A low-resistance portion is formed on each of the surfaces, and an electrode made of a plated metal is formed on each of the low-resistance portions of the flange portion, and the electrodes are connected to both end portions of the lead. At this time, since the winding portion is formed of a metal wire, the magnetic efficiency is high, and the external electrode can be a thin electrode of the present invention, so that an inductor having a small eddy current loss and a high Q value can be realized.

In the case where a laser is used as a method of local heating, the laser energy is concentrated in a narrow region, and thus a part of the ceramic body is melted and solidified, and a linear or spot-shaped laser irradiation mark is formed on the surface of the ceramic body. A low resistance portion is formed in the vicinity of the periphery thereof. The depth and width of the laser irradiation mark and the low resistance portion can be adjusted by the irradiation energy (wavelength, output, etc.) of the laser. Since the plating metal deposited in the low-resistance portion is fixed along the inner wall of the concave laser irradiation mark, the fixing strength of the plating metal (electrode) with respect to the ceramic body can be improved by the anchor effect.

In order to make the low resistance portion have almost no gap, the laser may be densely irradiated to the electrode formation region. At this time, since the low-resistance portion is also continuously formed, the plating metal is rapidly precipitated/growth, and the plating treatment time can be shortened. Further, "dense irradiation" means that the interval between the centers of the spots irradiated by the laser is equal to or narrower than the spread of the low-resistance portion. In other words, when the interval between the center of the spot of the laser irradiation is D and the diameter of the spot (the spread of the low resistance portion) is W, D W.

In the case where the laser is densely irradiated in the electrode formation region as described above, the number of times of emission is required, and the processing time is required. Therefore, it is also possible to dispersely illuminate the laser in the electrode formation region with a predetermined distance therebetween, thereby forming a plurality of low-resistance portions dispersed in the electrode formation region, and plating the metal deposited on the low-resistance portion as a nucleus to continue. The plating process is performed until the plating metals are connected to each other. Here, "dispersive irradiation" means that the interval between the centers of the spots of the laser irradiation is wider than the width of the low resistance portion. In other words, when the interval between the center of the spot of the laser irradiation is D and the diameter of the spot (the spread of the low resistance portion) is W, D>W. An advantage of the plating treatment is that if a plating metal is partially precipitated, the plating metal rapidly grows the portion as a core toward the periphery. With this advantage, the plated metal is deposited in a plurality of dispersed low-resistance portions, and this is used as a core to grow the plated metal to a region other than the low-resistance portion. Therefore, a homogeneous electrode can be formed over the entire electrode formation region. Therefore, it is possible to form an electrode of excellent quality without intensively irradiating a laser, and it is possible to shorten the laser processing time.

A ferrite is present as a representative ceramic material capable of reducing the resistance or the conductor by irradiating a laser. The ferrite is a ceramic containing iron oxide as a main component, and is, for example, a spinel ferrite, a hexagonal ferrite, a garnet ferrite, or the like. When the ferrite is irradiated with a laser, the irradiated portion becomes a high temperature, and the surface layer portion of the insulating ferrite is qualitatively changed to have conductivity. For electricity The ferrite of the sensor includes, for example, a Ni-Zn ferrite, a Ni-Cu-Zn ferrite, or the like. In the case of a Ni-Zn ferrite, it is considered that a part of Fe contained in the ferrite is reduced by laser irradiation, and there is a possibility that Ni and/or Zn are also reduced. In the case of a Ni-Cu-Zn ferrite, it is considered that Fe and/or Cu contained in the ferrite is reduced, and there is a possibility that Ni and/or Zn are also reduced.

As described above, according to the present invention, the electrode formation region of the sintered ceramic body is locally heated to form a low-resistance portion, and the ceramic body is subjected to a plating treatment to precipitate the plating metal on the low-resistance portion. The plating electrode is grown in the entire region of the electrode formation region, so that the electrode can be formed by a simple method. Further, as long as the region which can be locally heated can form an electrode in an arbitrary portion, it is possible to easily form an electrode having an arbitrary shape.

1‧‧‧Ceramic electronic parts

10‧‧‧Ceramic body

20‧‧‧Internal electrodes

21~23‧‧‧ coil conductor

21a, 23a‧‧‧ one end (lead)

30, 31‧‧‧ External electrodes

40‧‧‧Laser illumination marks

43‧‧‧Low resistance section

44‧‧‧Insulated area

45a‧‧‧Electroplated metal

45‧‧‧External electrode

L‧‧‧Laser

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a first embodiment of a ceramic electronic component of the present invention.

Fig. 2 is an exploded perspective view of the ceramic electronic component shown in Fig. 1;

3 is a perspective view showing a state in which a laser is irradiated to an external electrode forming region.

4 is a cross-sectional view showing a step of forming an external electrode.

Fig. 5 is an enlarged cross-sectional view showing an example of a low resistance portion.

Fig. 6 is a view showing an example of mounting of a ceramic electronic component of the present invention.

Fig. 7 is a cross-sectional view showing another example of a procedure of forming an external electrode.

Fig. 8 is a perspective view showing several embodiments of the ceramic electronic component of the present invention.

Figure 9 is a view showing a wound inductor of an example of a ceramic electronic component of the present invention. Figure.

Fig. 10 is a view showing another example of the wound inductor of the present invention.

Fig. 11 is a view showing a longitudinally wound type coil component as an example of a ceramic electronic component of the present invention.

Fig. 12 is a view showing a multi-terminal type electronic component as an example of the ceramic electronic component of the present invention.

Fig. 1 shows a chip inductor 1 as an example of a ceramic electronic component of the present invention. The inductor 1 includes a sintered ceramic body 10, and external electrodes 30 and 31 are formed at both end portions of the ceramic body 10 in the longitudinal direction. As shown in FIG. 1, the shape of the inductor 1 of this embodiment is a cube having a longer dimension in the X-axis direction than the dimensions in the Y-axis and Z-axis directions.

As shown in FIG. 2, the ceramic body 10 is obtained by laminating and sintering the insulator layers 12a to 12e mainly composed of Ni-Zn ferrite or Ni-Cu-Zn ferrite. The insulator layers 12a to 12e are sequentially laminated in the vertical direction (Z-axis direction). The coil conductors 21 to 23 constituting the internal electrode 20 are formed on the insulator layers 12b to 12d in the middle of the insulator layers 12a and 12e at the upper and lower ends. The three coil conductors 21 to 23 are connected to each other by the via-hole conductors 24 and 25, and are formed in a spiral shape as a whole. The coil conductors 21 to 23 and the via-hole conductors 24 and 25 are formed of a conductive material such as Au, Ag, Pd, Cu, or Ni. One end portion (lead portion) 21a of the coil conductor 21 is exposed at one end surface of the ceramic body 10 in the X-axis direction, and one end portion (lead portion) 23a of the coil conductor 23 is exposed at the other end surface of the ceramic body 10 in the X-axis direction. . Further, this embodiment shows an example in which the coil conductors 21 to 23 form a coil of 2 turns, but the number of turns is arbitrary, and the shape of the coil conductor and the number of layers of the insulator layer can be arbitrarily selected. In addition, the insulator layers 12a, 12e having no coil conductors The number of layers is also arbitrary.

As shown in FIG. 1, the external electrodes 30 and 31 are formed in a side view L shape so as to cover both end faces of the ceramic body 10 in the X-axis direction and a part of the upper surface (the bottom surface at the time of mounting). That is, when the ceramic body 10 is viewed from the Y direction, the external electrodes 30 and 31 are each formed in an L shape. The external electrode 30 is connected to the lead portion 23a of the coil conductor 23, and the external electrode 31 is connected to the lead portion 21a of the coil conductor 21. Further, the external electrodes 30 and 31 are formed by a plating treatment as will be described later, and examples of the material thereof include Cu, Au, Ag, Pd, Ni, Sn, and the like. Further, the external electrodes 30, 31 themselves may be composed of a plurality of layers of plated metal.

3 shows a case where the external electrodes 30, 31 are irradiated with the laser light L in the external electrode forming regions S1, S2 before being formed on the ceramic body 10. (a) of FIG. 3 shows an example in which the laser light L is continuously irradiated and scanned in the Y-axis direction (or an example in which the ceramic green body 10 is moved in the Y-axis direction). Further, the scanning direction is arbitrary, and may be an X-axis direction (or a Z-axis direction), a zigzag shape, or a wrap shape. A plurality of linear laser irradiation marks 40 are formed on the surface of the ceramic body 10 by the irradiation of the laser light L. Further, (a) of FIG. 3 shows an example in which linear laser irradiation marks 40 are formed in the X-axis direction at intervals, but the laser irradiation marks 40 may be densely formed so as to overlap each other. (b) of FIG. 3 shows an example in which the laser light L is irradiated in a dot shape. At this time, a plurality of dot-shaped laser irradiation marks 41 are dispersedly formed on the surface of the ceramic body 10. (c) of FIG. 3 shows an example in which the laser light L is irradiated in a dotted line shape. At this time, a plurality of dotted laser irradiation marks 42 are dispersedly formed on the surface of the ceramic body 10. In either case, it is preferable to uniformly irradiate the laser light L over the entire area of the external electrode forming regions S1, S2.

Fig. 4 shows a brief case of an example of a process of forming an external electrode. In particular, it is shown that the laser beam is linearly irradiated at a predetermined interval in the external electrode forming region. Happening.

(A) of FIG. 4 shows that a laser beam is irradiated to the external electrode forming region on the surface of the ceramic body 10, whereby a laser beam 40 having a V-shaped cross section or a U-shaped cross section is formed on the surface of the ceramic body 10. status. Further, (A) of FIG. 4 shows an example in which the laser light L is concentrated at one point, and the spot that actually irradiates the laser light L may have a certain area. This laser irradiation mark 40 is a mark which melts and solidifies the surface layer portion of the ceramic body 10 by laser irradiation. The central portion of the spot has the highest energy, and the ceramic material in this portion is easily changed in quality, and the cross section of the laser irradiation mark 40 is approximately V-shaped or approximately U-shaped. The insulating material (ferrite) constituting the ceramic body is qualitatively changed around the inner wall surface including the laser irradiation mark 40, and a conductor portion or a low resistance portion 43 having a lower resistance value than the insulating material is formed. Specifically, in the case where the ceramic body 10 is a Ni-Zn ferrite, it is conceivable to reduce a part of Fe contained in the ferrite by laser irradiation, and it is also possible to reduce Ni and/or Zn. Sex. In the case of Ni-Cu-Zn-based ferrite, Fe and/or Cu reduction contained in ferrite may be considered, and there is a possibility that Ni and/or Zn may also be reduced. The depth and width of the low-resistance portion 43 can be changed depending on the irradiation energy of the laser, the irradiation range, and the like.

(B) of FIG. 4 shows a state in which a plurality of laser irradiation marks 40 are formed at intervals D in the external electrode forming region by repeating laser irradiation. In this example, the interval D of the center of the spot of the laser irradiation is wider than the spread of the low-resistance portion 43 (for example, the average value of the diameter) W. Therefore, the insulating region 44 other than the low-resistance portion exists between the respective laser irradiation marks 40. This region 44 is a region in which the original insulating material constituting the ceramic body is not deformed and exposed.

(C) of FIG. 4 shows an initial state in which the ceramic body 10 in which the low-resistance portion 43 is formed by laser irradiation is immersed in the plating solution as described above. The current density of the low-resistance portion 43 having conductivity is higher than that of other portions, so the plating metal 45a is only in the low-resistance portion. The surface of 43 is precipitated and has not yet precipitated on the insulating region 44. In other words, no continuous external electrodes are formed in this stage.

(D) of FIG. 4 shows a state in which the plating is performed at the end. By continuing the plating process, the plating metal 45a deposited on the low-resistance portion 43 grows around the core and spreads to the insulating region 44 adjacent to the low-resistance portion 43. The plating process is continued until the adjacent plating metals 45a are connected to each other, whereby the continuous external electrode 45 can be formed. The growth rate of the plating metal in the region other than the external electrode formation region is slower than the growth rate of the plating metal in the external electrode formation region irradiated with the laser. Therefore, the plating treatment time is not strictly controlled, and the external electrode formation region can also be made. The plating metal is selectively grown. The formation time and thickness of the external electrode can be controlled by controlling the plating treatment time, voltage, or current. Further, an external electrode having a multilayer structure can be formed by performing an additional plating treatment on the external electrode 45 formed by the first plating treatment. At this time, since the external electrode 45 which has become a base is formed, the additional plating processing time is short.

- Experimental example -

Hereinafter, an experimental example in which the formation of the external electrode is actually performed will be described.

(1) A sintered ceramic body composed of a Ni-Cu-Zn ferrite is irradiated with a laser while scanning back and forth. The processing conditions are as follows, but the wavelength may be, for example, in any range from 532 nm to 10620 nm. The irradiation interval refers to the distance between the forward path and the return spot center of the returning laser.

(2) The ceramic body after the laser irradiation was plated under the following conditions. Specifically, barrel plating is used.

As a result of the plating treatment under the above-described conditions, a favorable Cu external electrode having an average thickness of 20 μm can be formed on the surface of the ceramic body. In addition, the same result is in the use of Ni-Zn It is also available in the case of ferrite. Further, as the plating solution, in addition to the copper pyrophosphate plating solution, a copper sulfate plating solution, a copper cyanide plating solution, or the like can be used.

-Evaluation-

With respect to the sample irradiated with the laser by the Ni-Cu-Zn ferrite and the sample irradiated with the laser, the XP, the X-ray photoelectron spectroscopy, and the Fe, Cu, and the electronic conversion method are used. The Zn and K-terminal XAFS (X-ray absorption microstructure) evaluated the valence of Fe, Cu, and Zn on the surface of the sample. As a result of XPS, the surface portion of the sample irradiated with the laser could not detect the metal component, and the lower layer could detect the metal component. Further, as a result of XAFS, the metal component of Cu can be detected for the surface portion of the sample irradiated with the laser. On the other hand, as a result of XAFS, the metal component of Fe cannot be detected in the surface layer portion of the sample irradiated with the laser, but the composition of the semiconductor of Fe and the composition of the insulator can be detected. It is also known that the ratio of the lower Fe ₂ + to Fe ₃ + is larger than the ratio of the entire ceramic body. According to the above, it is presumed that the heat of the laser processing decomposes the metal oxide contained in the ferrite, and the metal element of the ferrite of the lower layer of the ceramic body is reduced, and the surface layer portion of the ceramic body is residual heat. Reoxidation is achieved.

Fig. 5 shows an example of a cross-sectional structure of the low-resistance portion 43 thus formed, in which a reduction layer 43a is formed, and a surface layer thereof is covered with a reoxidation layer 43b composed of a semiconductor and/or an insulator component. The low-resistance portion is constituted by these reduction layers and reoxidation layers. In addition, laser irradiation is not limited to the atmospheric environment, and laser irradiation in a vacuum or N ₂ environment may be performed. However, in the case of laser irradiation in a vacuum or N ₂ environment, there is no reoxidation. The possibility of layers.

In the case where the above-described reoxidation layer is formed, the following effects can be considered. In other words, Fe ₃ O ₄ which is formed as a reoxidation layer has a property of being difficult to reoxidize at normal temperature, and also has an effect of suppressing oxidation of the reduction layer in the lower layer and suppressing temporal changes of the reoxidation layer itself. . Further, the reoxidation layer is a semiconductor and has a lower resistance value than a ferrite as an insulator. Therefore, the plating metal is easily precipitated on the reoxidation layer.

In the present embodiment, the external electrodes 30 and 31 are formed in an L shape in a side view (when the ceramic body 10 is viewed from the Y direction). In other words, the external electrodes 30, 31 are formed only on both end faces and the bottom face (at the time of mounting) of the inductor 1, and are not formed on the upper surface (at the time of mounting) and the two sides in the Y direction. Therefore, as shown in FIG. 6(a), when another electronic component 2 or a conductor is present near the inductor 1 in the mounted state, the risk of occurrence of a short circuit can be reduced. Further, when another electronic component 3 is attached adjacent to the Y direction of the inductor 1 as shown in FIG. 6( b ), the external electrodes 30 and 31 are not formed on both side surfaces of the inductor 1 in the Y direction. The insulation distance from the adjacent electronic component 3 can be ensured, and the distance between the solders applied to the external electrodes can also be ensured. Therefore, the risk of short circuit with the adjacent electronic component 3 can be reduced. As a result, in the case of the inductor 1 having the L-shaped external electrode, it is possible to perform further high-density mounting. Further, it also has an effect of reducing the stray capacitance as compared with the conventional external electrode.

Fig. 7 shows another example of the formation process of the external electrodes 30, 31, and particularly shows a case where the laser light L is densely irradiated to the external electrode formation region. "Densely illuminating" means that the interval D between the centers of the spots irradiated by the laser is equal to or wider than the spread of the low-resistance portion 43 (for example, the average value of the diameter) W or is narrower than the spread W of the low-resistance portion 43, and is formed in the adjacent laser. The lower resistance portions 43 on the lower side of the irradiation marks 40 are connected to each other (see FIG. 7(B)). However, it is not necessary to connect all of the low resistance portions 43. Therefore, the outer electrode forming region of the ceramic body 10 is almost The entire area is covered by the low resistance portion 43.

At this time, as shown in FIG. 7(C), the plating metal 45a is deposited on the surface of the low-resistance portion 43 in a short time from the start of the plating process, but these plating electrodes 45a are almost close, and thus the adjacent plating electrodes 45a are quickly connected to each other. . Therefore, the continuous external electrode 45 can be formed in a shorter time than in the case of FIG.

When the laser beam L is densely irradiated to the external electrode forming region as shown in FIG. 7 , the laser irradiation mark 40 is also densely formed, and thus the surface of the ceramic body 10 is partially cut off. Since the plating metal 45 is formed on the surface, the surface of the external electrode can be made almost the same height as the surface of the ceramic body 10 or lower than the surface of the ceramic body 10. Therefore, the thickness of the external electrode itself is small, and the amount of protrusion of the external electrode can be suppressed, and a further small-sized sheet component can be realized.

Fig. 8 shows various aspects of an external electrode formed by the present invention. (a) of FIG. 8 is formed at both ends of the ceramic body 10 The external electrodes 30, 31 of the font. Similarly to the embodiment of Fig. 1, the lead portions 21a and 23a (21a (not shown)) of the internal electrodes are exposed on both end faces of the ceramic body 10 in the X direction, and are connected to the external electrodes 30 and 31. In this example, the external electrodes 30 and 31 are formed on both end faces of the ceramic body 10 in the X direction and a part of the upper and lower surfaces (both sides in the Z direction), and external electrodes are not formed on both side faces in the Y direction. Therefore, the electronic component 1 can be mounted at a high density adjacent to each other in the Y direction.

(b) of FIG. 8 forms the external electrodes 30 and 31 only at both end portions of the upper surface (the bottom surface at the time of mounting) of the ceramic body 10. The external electrode is not formed on the other side. In this case, the end portions 21a and 23a of the internal electrode are not exposed at both end faces of the ceramic body 10 in the X direction, and are exposed only in parallel with the X direction on the upper surface. The external electrodes 30, 31 are connected to the end portions 23a, 21a of the internal electrodes, respectively. At this time, the insulator layer constituting the ceramic body 10 is laminated in the Y direction not in the Z direction. Since the external electrode is formed only on the bottom surface of the ceramic body 10, it is possible to realize an electronic component to which high-density mounting is applied.

In (c) of FIG. 8, a total of four external electrodes 30 to 33 are formed on both ends of the upper surface (the bottom surface of the mounting) of the ceramic body 10 in the X direction. In this case, the end portions (not shown) of the internal electrodes are not exposed on both end faces of the ceramic body 10 in the X direction, and are exposed only on the upper surface on which the external electrodes 30 to 33 are formed. As described above, the external electrode using the method of the present invention can be formed in any portion as long as it is capable of performing laser processing and plating treatment without any restriction.

Fig. 9 is an example in which the present invention is applied to electrode formation of a wound inductor. The ceramic body 50 is a core portion having flange portions 51 and 52 at both end portions and having a winding core portion 53 therebetween. As the core material, Ni-Zn ferrite, Ni-Cu-Zn ferrite, or the like can be used. The low-resistance portion is formed by the laser processing on the upper surface and the outer electrode forming region of the end surface of the flange portions 51, 52 of the core portion 50, and the external electrodes 54, 55 are formed thereon by plating. Further, a spiral low-resistance portion is formed by laser processing on the circumferential surface of the core portion 53, and the coil electrode 56 is formed thereon by plating. Both ends of the spiral low-resistance portion are subjected to laser processing so as to be continuous with the low-resistance portion of the external electrode forming region, so that both ends 56a, 56b of the coil electrode 56 and the external electrodes 54, 55 are respectively subjected to plating treatment. connection.

In this embodiment, the spiral low-resistance portion and the low-resistance portion for the external electrode can be continuously formed by laser processing. As the laser processing, for example, a method of fixing the laser position and rotating the core 50 and moving in the axial direction can be used. Since the coil electrode 56 and the external electrodes 54 and 55 can be simultaneously formed by the plating process, the manufacturing process of the inductor can be made efficient, and the manufacturing cost can be reduced. In addition, by the pair of coil electrodes 56 and the external electrodes 54, 55 It is also possible to form a multilayer structure by performing a plurality of plating processes. Further, in this embodiment, the coil electrode 56 and the external electrodes 54, 55 are formed by a plating process, but in the wound inductor (ferrite core) in which the wire is wound around the core portion, it is also possible to The plating process only forms an external electrode that is connected to the wire.

As described above, in the case where the coil electrode 56 and the external electrodes 54, 55 are formed by the same laser processing and plating treatment, there is a possibility that the electrodes 56, 54, 55 are almost constant in thickness. In particular, when the magnetic flux generated by the coil electrode 56 is to be large, the thickness of the coil electrode 56 is preferably made thicker than the thickness of the external electrodes 54, 55. In this case, for example, the laser intensity of the laser beam irradiated toward the core portion 53 may be higher than the laser intensity of the laser beam irradiated to the external electrode region, and the laser beam irradiated toward the core portion 53 may be used. The irradiation method of the laser that is irradiated to the external electrode region (for example, intermittent irradiation, continuous irradiation, expansion of the irradiation range, and the like) is changed. By increasing the laser intensity, the resistance value of the spiral low resistance portion is lower than the resistance value of the low resistance portion of the external electrode formation region, or the depth of the spiral low resistance portion is lower than the low resistance portion of the external electrode formation region. The depth is deep. Thereby, the thickness of the electrode 56 formed in the spiral low-resistance portion by the plating treatment can be made thicker than the thickness of the electrodes 54 and 55 formed in the low-resistance portion of the external electrode formation region.

Fig. 10 shows another application example of the wound inductor. The same portions or corresponding portions as those in FIG. 9 are denoted by the same reference numerals and the description thereof will not be repeated. The outer electrode forming regions on the upper surface, the outer side surface, and the lower surface of the flange portions 51, 52 of the core portion 50 are formed by laser processing with a low resistance portion on which external electrodes 54, 55 are formed by plating treatment. . Therefore, in this embodiment, as a whole, External electrodes 54, 55 of the shape. A lead wire 57 is wound around the circumferential surface of the winding core portion 53, and both ends 57a, 57b are connected to portions of the external electrodes 54, 55 formed on the upper surfaces of the flange portions 51, 52, respectively. Portions of the external electrodes 54, 55 formed on the lower surfaces of the flange portions 51, 52 are used as mounting electrodes. Further, the shape of the external electrodes 54, 55 is not limited For example, the zigzag may be formed only on the upper surface of the flange portions 51, 52 (the connection surface of the wires 57).

In this embodiment, since the external electrodes 54, 55 can be formed thinner than the wires 57, there is an effect of suppressing eddy current loss. That is, the magnetic flux generated by the wire 57 (indicated by the dotted arrow in Fig. 10) causes a loss of eddy current due to the interlinking with the external electrodes 54, 55, which is proportional to the square of the thickness of the external electrodes 54, 55 of the interlinkage. . Since the external electrodes 54, 55 formed by the method of the present invention can be formed thinner than a general external electrode, eddy current loss can be suppressed. Further, when the wire 57 is used as the winding wire, the magnetic flux density generated increases, so that an inductor having a high Q value can be obtained.

Fig. 11 shows an example in which the present invention is applied to a coil component (inductor) of a longitudinal winding type. The ceramic body 60 in this case is a ferrite core portion having flange portions 61 and 62 at both end portions and having a winding core portion 63 therebetween. The external electrode forming region on the upper surface of one flange portion 61 of the core portion 60 is formed with a low-resistance portion by laser processing or the like, and external electrodes 64 and 65 are formed thereon by plating. Further, a lead wire (not shown) having a coating layer is wound around the circumferential surface of the winding core portion 63, and both end portions thereof are connected to the external electrodes 64 and 65, respectively. Further, FIGS. 9 and 10 show an example in which two external electrodes 64 and 65 are formed. When two wires are used, four external electrodes may be formed on the flange portion 61.

Fig. 12 shows an example in which the present invention is applied to a multi-terminal type electronic component. The electronic component main body 70 is made of a ceramic green body, and a plurality of (here, six) external electrodes 71 to 76 are formed on both side surfaces in the longitudinal direction. Further, a part of the external electrodes 71 to 76 may be extended to the upper surface or the lower surface of the ceramic body 70. The external electrodes 71 to 76 are formed on the ceramic body 70 The internal electrodes or the circuit portions of the outer surface are connected. The external electrodes 71 to 76 in this case are also formed by local heating such as laser processing or subsequent plating treatment.

The present invention is applied to an example in which the external electrode of the laminated inductor and the electrode of the wound inductor (ferrite core) are formed, but are not limited thereto. The ceramic electronic component to which the present invention is applied is not limited to an inductor, and can be an electronic component using a ceramic body which is a low-resistance portion which is a deposition starting point of a plating electrode by using a laser irradiation qualitative change. application. That is, the material of the ceramic body is not limited to ferrite. Further, the structure of the electronic component is not limited to a structure having an internal electrode and a structure in which a plurality of insulating layers are laminated. As an electroplating treatment method, an example in which electroplating is used is shown, but electroless plating may also be used.

In the above embodiment, laser irradiation is used as a partial heating method, but irradiation with an electron beam, heating using a focusing furnace, or the like can also be applied. In either case, the energy of the heat source can be concentrated, and the external electrode forming region of the ceramic body is locally heated, so that the electrical characteristics of other regions are not impaired.

In the present invention, a laser is split, and the laser can be simultaneously irradiated at a plurality of positions.

Further, in the present invention, as compared with the case where the focus of the laser coincides, the focus of the laser can be shifted to increase the irradiation range of the laser.

In the case where the plating metal is formed of a plurality of layers, the present invention is not limited to the case where the lowermost layer of the plating metal is grown so as to extend toward the entire electrode formation region. It is also possible to grow the lowermost layer of the plating metal so as to expand toward a part of the electrode formation region, and to grow the upper layer of the plating metal so as to spread over the entire electrode formation region.

1‧‧‧Ceramic electronic parts

10‧‧‧Ceramic body

12a~12e‧‧‧Insulator layer

20‧‧‧Internal electrodes

21~23‧‧‧ coil conductor

21a, 23a‧‧‧ one end (lead)

24, 25‧‧‧ Through-hole conductor

Claims (18)

A method for producing a ceramic electronic component comprising: A: a step of preparing a sintered ceramic body containing a metal oxide; and B: performing an electrode formation region on a surface of the ceramic body a step of locally heating to form a low-resistance portion that reduces a part of the ceramic body; and C: plating the metal body on the low-resistance portion by plating the ceramic body The step of growing the above-described plating metal in such a manner as to spread to the entire electrode formation region. The method for producing a ceramic electronic component according to the first aspect of the invention, wherein the low-resistance portion includes a reduction layer obtained by reducing a part of a metal oxide contained in the ceramic body. A method of producing a ceramic electronic component according to the second aspect of the invention, wherein the surface layer of the reducing layer is covered with a reoxidation layer. The method for producing a ceramic electronic component according to any one of claims 1 to 3, wherein the method of local heating is any one of laser irradiation, electron beam irradiation, or local heating of a focus furnace. The method of manufacturing a ceramic electronic component according to the fourth aspect of the invention, wherein the plurality of low-resistance portions are formed by dispersing a laser at a plurality of positions of the electrode formation region at a predetermined distance apart In the electrode formation region, the plating metal is deposited as a core by the plating metal deposited on the low resistance portion, and the plating treatment is continued until the plating metals are connected to each other. The method of manufacturing a ceramic electronic component according to claim 4, wherein the continuous low resistance portion is formed in the electrode formation region by densely irradiating a laser to the electrode formation region, and the low resistance is The plating metal deposited on the portion is grown as a core, and the plating treatment is continued until the plating metal extends to the entire electrode formation region. The method for producing a ceramic electronic component according to any one of claims 1 to 3, wherein the plating treatment is performed by electrolytic plating. The method for producing a ceramic electronic component according to any one of claims 1 to 3, wherein the ceramic body is a ferrite. The method for producing a ceramic electronic component according to the eighth aspect of the invention, wherein the ceramic body is a Ni-Zn ferrite, and the low resistance portion is formed by partial reduction of Fe contained in the ferrite. The method for producing a ceramic electronic component according to the eighth aspect of the invention, wherein the ceramic body is a Ni-Cu-Zn ferrite, and the low resistance portion is made of Fe and Cu contained in the ferrite. At least one of the components is formed by reduction. A ceramic electronic component comprising: a sintered ceramic body comprising a metal oxide; and a low-resistance portion formed on a surface of the ceramic body and having a part of the metal oxide being qualitatively low Resistance; and An electrode composed of a plated metal formed on the low resistance portion. The ceramic electronic component according to claim 11, wherein the low resistance portion includes a reduction layer obtained by reducing a part of the metal oxide contained in the ceramic body. The ceramic electronic component of claim 12, wherein the surface layer of the reducing layer is covered by a reoxidation layer. The ceramic electronic component according to any one of claims 11 to 13, wherein the ceramic body is a ferrite. The ceramic electronic component according to any one of claims 11 to 13, wherein the ceramic body has a cubic shape, and an internal electrode is provided inside the ceramic body, and an end of the internal electrode is in the ceramic blank One of the surfaces of the body is exposed, and the low resistance portion is formed on a surface exposed at an end portion of the internal electrode, and an external electrode as the electrode is formed on the low resistance portion so as to cover an end portion of the internal electrode. The ceramic electronic component according to any one of claims 11 to 13, wherein the ceramic body has a flange portion at both end portions, and a ferrite core portion having a core portion therebetween, in the above-mentioned roll a low-resistance portion having a spiral shape is formed on a circumferential surface of the core portion, and a low-resistance portion connected to the spiral low-resistance portion is formed on a surface of the flange portion, and the low-resistance portion of the flange portion and the spiral a low-resistance portion continuously formed by the above An electrode made of electroplated metal. The ceramic electronic component of claim 16, wherein the film thickness of the electrode formed on the spiral low resistance portion is larger than the thickness of the electrode formed on the low resistance portion of the flange portion Thicker. The ceramic electronic component according to any one of claims 11 to 13, wherein the ceramic body has a flange portion at both end portions, and a ferrite core portion having a core portion therebetween, in the above-mentioned roll a lead wire is wound around a circumferential surface of the core, and the low-resistance portion is formed on a surface of the flange portion, and an electrode made of the plated metal is formed on a low-resistance portion of the flange portion, and the electrode and the wire are Connected at both ends.