JP2004146401A - Laminated electronic parts and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain thin laminated electronic parts having external electrodes, each of which has a proper electrical connection with an internal electrode and a small DC resistance and to obtain a method for manufacturing the same. <P>SOLUTION: The laminated electronic parts (laminated capacitor) include a laminate 2 formed by laminating a plurality of ceramic sheets and a plurality of internal electrodes, and external electrodes 3 electrically connected to lead parts of the internal electrodes on both end faces of the laminate 2. The electrodes 3 each includes a conductive film 31 formed in a state in which the lead parts of the internal electrodes are electrically connected in a ring state to four edges of the end face of the laminate 2, and a plating film 32 formed by electrolytically plating the end face formed with the film 31. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laminated electronic component and a method of manufacturing the same, particularly, a laminate formed by laminating a plurality of insulating sheets and a plurality of internal electrodes, such as a capacitor and an LC noise filter, and forming the laminate on an end face of the laminate. The present invention relates to a multilayer electronic component provided with external electrodes electrically connected to a lead portion of an electrode, and a method for manufacturing the same.
[0002]
[Prior art and problems]
In general, as a multilayer capacitor, a plurality of ceramic sheets on which internal electrodes are formed are stacked, and furthermore, protective layers of the ceramic sheets are stacked on the upper and lower surfaces thereof, and after firing, cut into predetermined external dimensions to form a stacked body. In the case of a two-terminal type, there is provided a laminate in which external electrodes electrically connected to the lead portions of the internal electrodes are provided on both end surfaces of the laminate.
[0003]
Conventionally, the external electrodes have been formed by applying and baking a conductive paste to the end surface of the laminate by, for example, a dipping method. However, an external electrode formed by applying and baking a conductive paste has a problem that the thickness is inevitably increased, which is incompatible with recent miniaturization of electronic components. Further, when the conductive paste is mainly composed of Cu, if the internal electrode is made of Ni, the electrical connection by baking is not always good, and the glass component contained in the conductive paste is not always good. However, there was a problem that the conductivity was hindered and the DC resistance between the external electrodes was increased.
[0004]
[Patent Document 1]
JP-A-63-169014 [0005]
On the other hand, Patent Literature 1 describes a method of depositing a conductive metal layer by electroless plating on the entire surface of an end face of a multilayer capacitor so that an internal electrode exposed on the end face is short-circuited.
[0006]
In this method of forming an external electrode, although a thin external electrode can be obtained, there is a problem that the plating growth is not sufficient and the direct current resistance increases because the process is only the growth of the plating from the internal electrode. are doing.
[0007]
Therefore, an object of the present invention is to provide a multilayer electronic component having an external electrode that is thin, has good electrical connection with an internal electrode, and has a small DC resistance, and a method of manufacturing the same.
[0008]
Means and Action for Solving the Problems
In order to achieve the above object, a laminated electronic component according to the present invention is configured such that a plurality of insulating sheets and a plurality of internal electrodes are laminated to form a laminate, and the internal electrodes are drawn to both end surfaces of the laminate. In the laminated electronic component provided with the external electrode electrically connected to the portion, the external electrode is composed of a conductive film and an electrolytic plating film, and the conductive film is formed of a ridge on each end face of the laminate. At least a ridge portion along the stacking direction of the internal electrodes is provided so as to be electrically connected to the lead portion, and the electrolytic plating film is connected to the conductive film at the ridge portion on each end surface of the laminate. It is characterized by being provided in. The conductive film is made of a conductive paste, a conductive resin, or the like.
[0009]
In the multilayer electronic component having the above configuration, since the electrolytic plating is performed on the end surface of the laminate in which the conductive film electrically connected to the lead portion is formed, the growth of the plating film is good, Normally, Ni, which is the same material as the internal electrode, is used as the plating material, so that its connectivity is good and the DC resistance is small. In addition, the thickness of the plating film is small, so that the area of the stacked body can be increased accordingly, and the degree of freedom in designing the internal electrode increases.
[0010]
In the laminated electronic component according to the present invention, the lead portion of the internal electrode may be extended to a side surface of the laminate, and the electrolytic plating film may be provided on a side surface of the laminate so as to be connected to the conductive film. The amount of contact between the lead portion and the conductive film increases, and a more stable plating film is formed.
[0011]
Further, the conductive film may be formed on at least one ridge on both end surfaces of the laminate, but is preferably provided in a ring shape on each of the four ridges. A more stable plating film can be formed, and the directionality at the time of mounting the electronic component is not limited.
[0012]
Further, it is preferable that the interval between the lead portions in the laminating direction is not more than twice the thickness of the electrolytic plating film. In electrolytic plating, the plating film grows in the vertical and horizontal directions starting from the lead-out portion, but by setting the interval between the lead-out portions to twice or less the thickness of the plating film, there is no gap in the end face of the laminated body without any gap. Is formed.
[0013]
Further, an external electrode different from the external electrodes on the both end faces may be provided on a side surface of the laminate adjacent to the ridge. The step of providing another external electrode can be omitted.
[0014]
On the other hand, the method for manufacturing a laminated electronic component according to the present invention includes the steps of: laminating a plurality of insulating sheets and a plurality of internal electrodes to form a laminate, and electrically connecting a lead portion of the internal electrode to an end surface of the laminate. In the method for manufacturing a laminated electronic component provided with external electrodes connected to the semiconductor device, the step of forming the external electrodes may include drawing out the conductive paste to at least a ridge of an end surface of the laminated body along a laminating direction of the internal electrodes. A step of applying the conductive paste so as to be in contact with the portion, a step of baking or thermosetting the conductive paste to form a conductive film, and applying an electrolytic plating to an end face of the laminate to be connected to the conductive film of the ridge. Forming an electrolytic plating film as described above.
[0015]
In the manufacturing method having the above configuration, since the end face of the laminate formed with the conductive film electrically connected to the lead portion is subjected to electrolytic plating, the growth of the plated film is good, and the plating material is usually used. Since Ni, which is the same material as the internal electrodes, is used, its connectivity is good and the DC resistance is small. In addition, the thickness of the plating film is small, so that the area of the stacked body can be increased accordingly, and the degree of freedom in designing the internal electrode increases.
[0016]
In the manufacturing method according to the present invention, when an external electrode other than the external electrode is provided on the surface of the laminate, a conductive paste is applied to at least a ridge portion of the end surface of the laminate along the laminating direction of the internal electrodes. In addition, if a conductive paste to be an external electrode different from the external electrode is simultaneously applied to the side surface adjacent to the ridge, the manufacturing process is simplified.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a multilayer electronic component and a method of manufacturing the same according to the present invention will be described with reference to the accompanying drawings.
[0018]
(1st Embodiment, FIGS. 1-7)
FIG. 1 shows the appearance of a two-terminal multilayer ceramic capacitor 1A according to a first embodiment. In this capacitor 1A, external electrodes 3 formed on both end surfaces of a laminated body 2 are constituted by a conductive film 31 and a plating film 32.
[0019]
FIG. 2 shows the appearance of the laminate 2 and FIG. In the laminate 2, an internal electrode 5 for forming a capacitance is formed on the surface of a plurality of dielectric ceramic green sheets 4 together with a lead portion 5a, and a required number of these sheets 4 are laminated. An outer layer is formed by laminating plain ceramic green sheets on the upper and lower surfaces, fired, and then cut into predetermined external dimensions.
[0020]
The length L of the laminate 2 is 1.6 mm, the width W is 0.8 mm, and the height T is 0.8 mm, but is not limited thereto. Further, W> T may be satisfied, and FIG. 2 illustrates W> T. Further, the gap g between the end of the lead portion 5a and the side surface of the laminate 2 is 150 μm, and the thickness t of the outer layer is 150 μm. The values of the gaps g and t are merely examples.
[0021]
The steps of forming the external electrodes 3 on the laminate 2 are as follows. First, the laminate 2 is packed in a well-known holding / supply plate (not shown), and the height is made uniform by performing cueing. As shown in FIG. 4, this laminate 2 is placed on a paste supply plate 10, and a conductive paste 31 ′ containing Cu as a main component is extruded from supply ports 11, 11, and edges of both end surfaces of the laminate 2 are ridged. Apply to the part. By repeating this coating process four times, the conductive film 31 is formed in a ring shape on the four ridges on the end face of the laminate 2.
[0022]
In FIG. 5, the hatched portion is the conductive film 31 thus formed. The conductive film 31 is in contact with the exposed lead portion 5 a at the end face of the multilayer body 2 and also extends around the side face of the multilayer body 2.
[0023]
As described above, the reason why the gap g between the end portion of the lead portion 5a and the side surface of the multilayer body 2 is 150 μm and the thickness t of the outer layer is 150 μm is to ensure that the conductive paste film 31 comes into contact with the lead portion 5a. It is.
[0024]
After that, the conductive paste film 31 is baked by controlling the temperature and the atmosphere, and the internal electrode 5 and the conductive paste film 31 (hereinafter, referred to as conductive film 31) are electrically connected.
[0025]
Next, electrolytic plating is performed on the end face of the laminate 2 to form a Ni plating film 32 and an Sn plating film (only the Ni plating film is shown in FIG. 6) thereon. At the time of this electrolytic plating, since the lead portion 5a of the internal electrode 5 and the conductive film 31 are electrically connected to each other at the end surface of the laminate 2, metal is deposited from the lead portion 5a not covered with the conductive film 31. Then, the plating film 32 is formed to cover the entire end face by growing the plating.
[0026]
Since the internal electrode 5 is made of Ni and the plating film 32 is made of Ni, the electrical connection between the two is good and the DC resistance is small, in combination with the good plating growth. Further, the thickness D of the plating film 32 is 0.5 to 10 μm, and the thickness of the conductive film 31 is 15 to 25 μm in a large portion. In the electrode film formed by the conventional thick film forming method, the center portion of the end face is the thickest, and its thickness is 30 to 70 μm. Therefore, the thickness of the external electrode 3 in the laminate 2 is smaller by about 100 μm on both end surfaces than the conventional thick film electrode, and the dimension L of the laminate 2 can be increased accordingly.
[0027]
According to the electrolytic plating, the plating film 32 grows in the vertical direction and the horizontal direction. When the distance A between the lead portions 5a is set to be equal to or less than twice the thickness D of the plating film 32, the plating film 32 grows with the thickness D substantially as a radius starting from the lead portion 5a, and the plating film 32 having no gap is obtained. Can be
[0028]
In electrolytic plating, a steel ball 15 shown in FIG. 7 is used as a medium. The steel ball 15 used here has a diameter of 100 to 400 μm. On the other hand, in the end face of the laminated body 2, the drawer 5a is pulled in from the end face by several μm due to shrinkage during firing.
[0029]
That is, in the case where the interval A between the lead portions 5a is 1 to 20 μm, the thickness B of the lead portions 5a is 0.4 to 1 μm, and the drawing amount C of the lead portions 5a is several μm, the steel ball having a diameter of 100 to 400 μm. When the steel ball 15 is used, the steel ball 15 does not come into direct contact with the lead portion 5a. However, since the conductive film 31 is electrically connected to the lead portion 5a, a current flows through the steel ball 15 to the lead portion 5a. The metal flows and deposits well.
[0030]
However, when the conductive film 31 is not formed, plating does not deposit on the lead portion 5a. In addition, if the diameter of the steel ball is set to 100 μm or less, the steel ball comes into direct contact with the drawer 5a. However, since the number of contacts is reduced, metal deposition becomes impossible or it takes a long time, Not practical.
[0031]
(Second embodiment, see FIG. 8)
FIG. 8 shows the appearance of the multilayer ceramic capacitor 1B according to the second embodiment. This capacitor 1B is of a three-terminal type in which, in addition to the external electrodes 3, a ground external electrode 6 is formed by applying a conductive paste to the four sides of the laminate 2 at the center thereof.
[0032]
The external electrode 3 is composed of a conductive film 31 and a plating film 32 as in the capacitor 1A of the first embodiment, and the forming process is as described above.
[0033]
As for the external electrode 6, as shown in FIG. 4, the conductive paste 31 'is applied using the paste supply plate 10. In this case, it goes without saying that one supply port 11 is added. This application step is performed simultaneously with the application of the conductive paste film 31. Therefore, even a three-terminal type or multi-terminal type multilayer electronic component as described above can be manufactured without increasing the number of steps.
[0034]
In the case of a three-terminal capacitor using a laminate having a length L of 1.6 mm, a width W of 0.8 mm and a height of 0.8 mm, in the second embodiment, the direct current between the external electrodes 3 The resistance value was 3.5 mΩ. On the other hand, it was 4.5 mΩ for a three-terminal capacitor of the same size in which external electrodes were formed by a conventional thick film forming method. That is, in the second embodiment, the DC resistance value is reduced by about 20% as compared with the conventional one, and the rated current value can be improved.
[0035]
(Third embodiment, see FIG. 9)
FIG. 9A shows an appearance of a multilayer ceramic capacitor 1C according to the third embodiment in an intermediate product state. This capacitor 1C differs from the capacitor 1A of the first embodiment in that the conductive film 31 of the external electrode 3 is formed only on two opposing ridges along the lamination direction of the internal electrodes. A plating film 32 (see FIG. 9B) is formed on the end face of the laminate 2 by the same electrolytic plating as described above.
[0036]
The third embodiment has an advantage that the application step using the paste supply plate 10 shown in FIG. 4 can be performed only twice.
[0037]
In this capacitor 1C, when it is mounted on a substrate, it is necessary to set the surface on which the conductive film 31 is formed as a mounting surface as shown in FIG. It becomes. In the multilayer capacitors 1A and 1B, since the conductive films 31 are formed on the four ridges, it is not always necessary to determine the directionality at the time of mounting.
[0038]
(Fourth embodiment, see FIGS. 10 to 11)
FIG. 10 shows a multilayer ceramic capacitor 1D according to a fourth embodiment. FIGS. 10A, 10B, and 10C show the order of each process. This capacitor 1D is provided with the internal electrode 5 shown in FIG. 11, and the lead portion 5a is provided at both ends of the side surface of the laminate 2 (both ends of the side surface adjacent to the end surface and orthogonal to the internal electrode 5). Is also pulled out and exposed.
[0039]
In the capacitor 1D, similarly to the capacitor 1C of the third embodiment, the conductive film 31 constituting the external electrode 3 is formed only on two opposing ridges along the lamination direction of the internal electrode 5. . The lead portion 5a is also exposed at both ends of the side surface of the multilayer body 2, and the conductive film 31 contacts the lead portion 5a with a larger area.
[0040]
Further, a plating film 32 is formed on the end face of the laminate 2 by the same electrolytic plating as described above. Here, the plating film 32 is formed not only on the end face but also on the exposed side surface of the lead portion 5a so as to be continuous with the conductive film 31. Therefore, the external electrode 3 also largely goes around the side surface of the multilayer body 2, so that the connection with the internal electrode 5 becomes more reliable and the soldering at the time of mounting on the substrate becomes stable and reliable.
[0041]
(Other embodiments)
The multilayer electronic component and the method of manufacturing the same according to the present invention are not limited to the above embodiments, but can be variously modified within the scope of the invention.
[0042]
In particular, as a method for applying the conductive paste film, various methods and a coating device can be adopted other than the method using the paste supply plate 10 shown in FIG.
[0043]
Further, the shape of the lead portion of the internal electrode is arbitrary, and even in the first, second, and third embodiments, the lead portion shown in the fourth embodiment, that is, also exposed to the side surface of the laminate. A drawer having a shape may be formed.
[0044]
Further, the ridge forming the conductive film may be at least a ridge along the lamination direction of the internal electrodes. In the first embodiment, the ridge is formed along the lamination direction of the internal electrodes as in the third and fourth embodiments. A conductive film may be formed only on two opposing ridges. Conversely, in the third and fourth embodiments, similarly to the first and second embodiments, a conductive film may be formed in a ring shape on each of four ridges.
[0045]
Further, the conductive film is not limited to one formed by baking a conductive paste film as described in each of the above embodiments, but may be formed by applying a conductive resin and thermally curing the resin. When a conductive resin is used, it is effective in improving the bending strength of the multilayer electronic component, and it is particularly effective to form it on a ridge.
[0046]
Note that the present invention can of course be applied to various electronic components such as inductors and LC noise filters other than capacitors.
[0047]
【The invention's effect】
As is apparent from the above description, according to the present invention, a conductive film formed on at least one ridge on both end surfaces of the laminate, and an electroplating formed on the end surface of the laminate on which the conductive film is formed Since the external electrode is composed of the plated film and the external electrode, the thickness at the end face of the external electrode is small, the electrical connection with the internal electrode is good, and a laminated electronic component having a low DC resistance is obtained. Can be.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a first embodiment of a multilayer capacitor according to the present invention.
FIG. 2 is a perspective view showing a laminate of the first embodiment.
FIG. 3 is a plan view showing the shape of an internal electrode according to the first embodiment.
FIG. 4 is a schematic explanatory view showing a step of applying a conductive paste film in the first embodiment.
FIG. 5 is a perspective view showing an intermediate product in which a conductive film is formed on an edge of an end face of the laminate in the first embodiment.
FIG. 6 is a cross-sectional view showing an electrolytic plating film formed on an end face of the laminate.
FIG. 7 is an explanatory view of an electrolytic plating step.
FIG. 8 is a perspective view showing a second embodiment of the multilayer capacitor according to the present invention.
9A and 9B show a third embodiment of the multilayer capacitor according to the present invention, wherein FIG. 9A is a perspective view showing a state where a conductive film is formed, and FIG. 9B is a perspective view showing a mounting direction.
10A and 10B show a multilayer capacitor according to a fourth embodiment of the present invention, wherein FIG. 10A is a perspective view of a multilayer body, FIG. 10B is a perspective view of a state in which a conductive film is formed, and FIG. FIG.
FIG. 11 is a plan view showing the shape of an internal electrode according to the fourth embodiment.
[Explanation of symbols]
1A, 1B, 1C, 1D: Multilayer ceramic capacitor 2: Laminate 3: External electrode 4: Ceramic green sheet 5: Internal electrode 5a: Leader 31: Conductive film 32: Plating film

Claims (10)

In a laminated electronic component, a laminated body is formed by laminating a plurality of insulating sheets and a plurality of internal electrodes, and external electrodes electrically connected to lead portions of the internal electrodes are provided on both end surfaces of the laminated body. ,
The external electrode is composed of a conductive film and an electrolytic plating film,
The conductive film is provided so as to be electrically connected to the lead-out portion at least at a ridge along a stacking direction of the internal electrodes among ridges of each end face of the laminate,
The electrolytic plating film is provided on each end face of the laminate so as to be connected to the conductive film at the ridge portion,
A laminated electronic component characterized by the following. The lead-out portion of the internal electrode is drawn out to a side surface of the laminate, and the electrolytic plating film is provided on a side surface of the laminate so as to be connected to the conductive film. The laminated electronic component as described. The multilayer electronic component according to claim 1, wherein the conductive film is provided in a ring shape at each of four ridges on both end surfaces of the multilayer body. 4. The multilayer electronic component according to claim 1, wherein an interval between the lead portions in a laminating direction is equal to or less than twice a thickness of the electrolytic plating film. 5. The external electrode different from the external electrodes on the both end surfaces is provided on a side surface adjacent to the ridge portion of the laminate, the external electrode being provided on the side surface thereof. 3. The laminated electronic component according to item 1. The multilayer electronic component according to claim 1, wherein the conductive film is made of a conductive paste. The multilayer electronic component according to claim 1, wherein the conductive film is made of a conductive resin. A laminated electronic component in which a plurality of insulating sheets and a plurality of internal electrodes are laminated to form a laminate, and an external electrode electrically connected to a lead-out portion of the internal electrode is formed on an end surface of the laminate. In the manufacturing method,
The step of forming the external electrode,
A step of applying a conductive paste on at least the ridges along the stacking direction of the internal electrodes on the end surfaces of the stacked body so as to be in contact with the lead portion,
Baking or thermosetting the conductive paste to form a conductive film,
Electroplating the end face of the laminate, forming an electrolytic plating film so as to be connected to the conductive film of the ridge,
A method for manufacturing a laminated electronic component, comprising: 9. The method according to claim 8, wherein the conductive film is formed in a ring shape on each of four edges of the end surface of the multilayer body. 10. A conductive paste is applied to at least the ridges along the stacking direction of the internal electrodes on the end surfaces of the laminate, and the conductive paste to be an external electrode different from the external electrode is simultaneously applied to the side surface adjacent to the ridges. The method for manufacturing a multilayer electronic component according to claim 8, wherein the method is applied.

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