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Patent Application Titled "Multilayer Ceramic Electronic Component" Published Online

June 17, 2014



By a News Reporter-Staff News Editor at China Weekly News -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors AKAZAWA, Teppei (Nagaokakyo-shi, JP); HADANO, Kenjiro (Nagaokakyo-shi, JP); SAKURATANI, Masahiro (Nagaokakyo-shi, JP), filed on January 29, 2014, was made available online on June 5, 2014.

The assignee for this patent application is Murata Manufacturing Co., Ltd.

Reporters obtained the following quote from the background information supplied by the inventors: "The present invention relates to a multilayer ceramic electronic component. In particular, the present invention relates to a multilayer ceramic electronic component that includes external electrodes including plated films provided on the surfaces of a ceramic body.

"Electronic equipment such as mobile phones, notebook computers, digital cameras, and digital audio equipment is becoming more and more compact. A large number of multilayer ceramic electronic components that enable the size of such an electronic device to be reduced and the performance thereof to be improved are used therein.

"A typical multilayer ceramic electronic component includes a ceramic body that includes a plurality of ceramic layers formed on one another, internal electrodes formed inside the ceramic body, and an external electrode formed on a surface of the ceramic body. A multilayer ceramic electronic component is disposed on a conductive land of a mount board and is then mounted onto the board by a conductive bonding material, such as solder.

"There is a growing demand for a multilayer ceramic electronic component having a reduced size.

"However, in general, the characteristics of a multilayer ceramic electronic component tend to deteriorate when the size of the multilayer ceramic electronic component is reduced because an effective area in which internal electrodes overlap one another is reduced.

"In a multi-terminal multilayer ceramic electronic component, it is necessary to form a plurality of external electrodes at a fine pitch. Paste-applying precision in a conventional thick-film paste firing method is limited. Therefore, it is difficult to form external electrodes with high precision when the conventional method is used.

"To overcome the above difficulty, a method of forming external electrodes by plating has been proposed. With this method, it is possible to form a thin flat external electrode, which enables an increase in the effective area of the internal electrodes. In addition, since metal is deposited at the exposed edges of internal electrodes, it is possible to form external electrodes with high precision even when a fine pitch is required.

"The use of dummy conductors (anchor tabs), for the purpose of improving the reliability of the growth of a plated film when external electrodes are formed directly by plating, that do not substantially contribute to the electric characteristics is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2004-327983. According to Japanese Unexamined Patent Application Publication No. 2004-327983, if the technique disclosed therein is used, it is possible to deposit metal not only at the exposed edges of internal electrodes but also at the exposed edges of dummy conductors. According to the Japanese Unexamined Patent Application Publication No. 2004-327983, this makes it possible to grow a plated film with increased reliability.

"However, even when the method disclosed in the Japanese Unexamined Patent Application Publication No. 2004-327983 is used, a problem of insufficient growth sometimes occurs when attempting to form a plated film by applying electrolytic plating to an electronic component having a small size of, for example, 1608 (approx. 1.6.times.0.8.times.0.8 mm) or less. Specifically, with electrolytic plating, a current is applied when a medium, such as a steel ball, is brought into contact with the exposed portions of internal electrodes and dummy conductors. As a result, metal is deposited at the exposed portions. However, as the size of the electronic component is reduced, the area of an exposed portion is reduced. Therefore, the probability of successful contact of the medium and the exposed portion is reduced."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "Preferred embodiments of the present invention provide a multilayer ceramic electronic component that has a structure that overcomes the above-described problems.

"A multilayer ceramic electronic component according to a preferred embodiment of the present invention preferably includes a ceramic body that includes a plurality of ceramic layers disposed on one another, the ceramic body including a first main surface and a second main surface arranged opposite to each other, a first side surface and a second side surface arranged opposite to each other, and a first end surface and a second end surface arranged opposite to each other, each of the first main surface, the second main surface, the first side surface, the second side surface, the first end surface, and the second end surface defining a portion of superficies of the ceramic body, a first internal electrode that is provided inside the ceramic body and includes a first overlap section and a first lead-out section, the first lead-out section extending from the first overlap section to a portion of the superficies of the ceramic body, a second internal electrode that is provided inside the ceramic body and includes a second overlap section and at least two second lead-out sections, the second overlap section being arranged opposite to the first overlap section with one of the plurality of ceramic layers sandwiched therebetween, each of the at least two second lead-out sections extending from the second overlap section to a portion of the superficies of the ceramic body, a first external electrode that is provided on a portion of the superficies of the ceramic body and covers an exposed edge of the first lead-out section, and a second external electrode that is provided on a portion or across a portion of the superficies of the ceramic body and includes a plated film that directly covers exposed edges of the second lead-out sections, the second external electrode being connected at a potential that is different from that of the first external electrode.

"When a region of the ceramic body in layers in which neither of the first internal electrode and the second internal electrode is provided as viewed in a direction in which the plurality of ceramic layers are provided on one another is defined as a non-effective layer region, a dummy lead-through conductor is provided in the non-effective layer region so as to lead to at least two locations on some portions of the superficies of the ceramic body and to be electrically connected to the second external electrode.

"According to a preferred embodiment of the present invention, preferably, the second internal electrode extends continuously from the first side surface to the second side surface, the second external electrode is provided on or extends across the first side surface and the second side surface, and the dummy lead-through conductor extends continuously from the first side surface to the second side surface.

"The second external electrode may preferably be provided separately on, or separately and primarily on, the first side surface and the second side surface, such that at least one second external electrode is provided on the first side surface and at least one second external electrode is provided on the second side surface. Alternatively, the plated film of the second external electrode may preferably be arranged to surround the first side surface, the second side surface, the first main surface, and the second main surface.

"In the above-described structure, at least a portion of the dummy lead-through conductor may be exposed on the first main surface and the second main surface.

"In a structure in which the plated film of the second external electrode is arranged so as to surround the first side surface, the second side surface, the first main surface, and the second main surface, it is preferable for at least a portion of the dummy lead-through conductor to be exposed on the first main surface and the second main surface from the first side surface to the second side surface.

"It is also preferable for the first internal electrode to extend continuously from the first end surface to the second end surface, and for the first external electrode to be provided separately on, or separately and primarily on, the first end surface and the second end surface, such that at least one first external electrode is provided on the first end surface and at least one first external electrode is provided on the second end surface.

"In a multilayer ceramic electronic component according to a preferred embodiment of the present invention, the dummy lead-through conductor preferably has a rectangular or substantially rectangular shape, for example.

"The dummy lead-through conductor is preferably disposed in the non-effective layer region so as to lead to at least two location of the superficies of the ceramic body, or, in other words, so as to lead through the ceramic body. In addition, the dummy lead-through conductor is preferably electrically connected to the second external electrode. Since the dummy lead-through conductor includes edges that are exposed at, at least, two locations of the superficies of the ceramic body, when a conductive medium, such as a steel ball, is brought into contact with one of the plurality of exposed edges of the dummy lead-through conductor, a current is also applied to the other exposed edges. This means that the probability of successful contact with the medium increases, which results in improved electrification efficiency. With this configuration, it is possible to reduce the plating time required to form a plated film as the underlying layer of the second external electrode.

"Thus, even though the required size of a multilayer ceramic electronic component is decreasing, it is possible to efficiently form the plated film of the second external electrode efficiently.

"The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 is a perspective view that illustrates a multilayer ceramic capacitor, which is an example of a multilayer ceramic electronic component according to a first preferred embodiment of the present invention.

"FIG. 2 is a sectional view taken along a plane parallel to the side surfaces of a ceramic body of the multilayer ceramic capacitor illustrated in FIG. 1.

"FIG. 3 is a sectional view taken along a plane parallel to the end surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 1.

"FIG. 4 is a sectional view taken along a plane parallel to the main surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 1, wherein a first internal electrode extends along the plane.

"FIG. 5 is a sectional view taken along a plane parallel to the main surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 1, wherein a second internal electrode extends along the plane.

"FIG. 6 is a sectional view taken along a plane parallel to the main surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 1, wherein a dummy lead-through conductor extends along the plane.

"FIG. 7 is a perspective view that illustrates a multilayer ceramic capacitor, which is an example of a multilayer ceramic electronic component according to a second preferred embodiment of the present invention.

"FIG. 8 is a sectional view taken along a plane parallel to the end surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 7.

"FIG. 9 is a partially enlarged view of FIG. 8.

"FIG. 10 is a sectional view that illustrates a multilayer ceramic capacitor, which is an example of a multilayer ceramic electronic component according to a third preferred embodiment of the present invention, wherein the sectional view is taken along a plane parallel to the side surfaces of the ceramic body thereof.

"FIG. 11 is a sectional view taken along a plane parallel to the end surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 10.

"FIG. 12 is a sectional view taken along a plane parallel to the main surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 10, wherein the first internal electrode extends along the plane.

"FIG. 13 is a sectional view taken along a plane parallel to the main surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 10, wherein the second internal electrode extends along the plane.

"FIG. 14 is a sectional view taken along a plane parallel to the main surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 10, wherein the dummy lead-through conductor extends along the plane.

"FIG. 15 is a sectional view that illustrates a multilayer ceramic capacitor, which is an example of a multilayer ceramic electronic component according to a fourth preferred embodiment of the present invention, wherein the sectional view is taken along a plane parallel to the side surfaces of the ceramic body thereof.

"FIG. 16 is a sectional view taken along a plane parallel to the end surfaces of the ceramic body of the multilayer ceramic capacitor illustrated in FIG. 15."

For more information, see this patent application: AKAZAWA, Teppei; HADANO, Kenjiro; SAKURATANI, Masahiro. Multilayer Ceramic Electronic Component. Filed January 29, 2014 and posted June 5, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=3715&p=75&f=G&l=50&d=PG01&S1=20140529.PD.&OS=PD/20140529&RS=PD/20140529

Keywords for this news article include: Asia, Murata Manufacturing Co. Ltd.

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Source: China Weekly News


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