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Researchers Submit Patent Application, "Multilayer Ceramic Capacitor and Method of Manufacturing the Same", for Approval

July 24, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors KIM, Kyu Ree (Suwon, KR); LEE, Byoung Hwa (Suwon, KR); CHAE, Eun Hyuk (Suwon, KR); KIM, Doo Young (Suwon, KR), filed on July 23, 2013, was made available online on July 10, 2014.

The patent's assignee is Samsung Electro-mechanics Co., Ltd.

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to a multilayer ceramic capacitor and a method of manufacturing the same.

"A multilayer ceramic capacitor, a laminated chip electronic component, is a chip-type condenser installed on a printed circuit board (PCB) of various electronic products such as imaging devices (or video display apparatuses) such as liquid crystal displays (LCDs), plasma display panels (PDPs), and the like, computers, personal digital assistants (PDAs), portable phones, and the like, to charge and discharge electricity.

"A multilayer ceramic capacitor (MLCC), having advantages such as compactness, guaranteed high capacitance, and ease of mountability, may be used as a component in various electronic devices.

"Recently, as performance of portable smart devices such as smartphones, tablet PCs, and the like, has been enhanced, a driving speed of an application processor (AP) handling calculation has been increased.

"The increase in a driving speed of an AP requires a current having a higher frequency to be promptly supplied to the AP.

"An MLCC serves to supply a current to such an AP.

"Thus, in order to promptly supply a high frequency current, an MLCC having low equivalent series inductance (ESL) may be used or an MLCC may be embedded in a board to maximally reduce a distance to the AP therefrom.

"However, using an MLCC having low ESL may trigger a different problem in terms of structure, so recently, research into an MLCC embedded in a board has been actively conducted.

"Meanwhile, as portable smart devices are reduced in weight and thickness, a thickness of a board in which an MLCC is embedded has also been reduced.

"In general, an embedded MLCC is designed to be thicker than a board core by about 3 .mu.m.

"A thickness of a currently used board core is less than 100 .mu.m, so an MLCC is required to have a thickness of about 130 .mu.m. However, recently, as the thickness of a board core has been reduced, the thickness of an MLCC has also been required to be reduced

"In order to reduce the thickness of an MLCC, a thickness of a ceramic body, an external electrode, and a plated layer should be reduced. A thickness of the plated layer may be maintained to be at least 5 .mu.m or greater in consideration of an error in via processing through a laser when an MLC is embedded, so a method of reducing a thickness of a ceramic body and an external electrode may largely be used.

"Here, a reduction in a thickness of a ceramic body may reduce the strength of the ceramic body. Thus, an excessive reduction in the thickness of the ceramic body may cause cracks in the ceramic body due to sintering shrinkage stress and plating stress concentrated on end portions of an external electrode. In particular, a generation frequency of cracks may be increased when a ceramic body has a thickness of less than 80 .mu.m.

"Patent document 1 below relates to an MLCC including a ceramic body including a plurality of dielectric layers and internal electrodes, and external electrodes, but without disclosing a ratio between a thickness of a ceramic body and a thickness of a band of an external electrode. Patent document 2 relates to an MLCC including a ceramic body including a plurality of dielectric layers and internal electrodes, and external electrodes, but without disclosing a ratio between a thickness of a ceramic body and a thickness of a band of an external electrode."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "In the related art, a novel scheme regarding a multilayer ceramic capacitor (MLCC), capable of reducing a generation of cracks in a ceramic body without degrading reliability, by adjusting ratios of thicknesses of a ceramic body, an external electrode, and a plated layer of an MLCC, is required.

"According to an aspect of the present invention, there is provided a multilayer ceramic capacitor including: a ceramic body in which a plurality of dielectric layers are laminated; a plurality of first and second internal electrodes formed to be alternately exposed to both end surfaces of the ceramic body with the dielectric layer interposed therebetween; and first and second external electrodes formed on both end surfaces of the ceramic body and electrically connected to the first and second internal electrodes, wherein when it is defined that (or it is assumed that) a thickness of a band of the first and second external electrodes is T1 and a thickness of the ceramic body is T2, a ratio (T1/T2) of the thickness of the band of the first or second external electrode to the thickness of the ceramic body is equal to or less than 0.18.

"The thickness of the ceramic body may be equal to or less than 100 .mu.m.

"The MLCC may further include first and second plated layers covering the first and second external electrodes, respectively, and when it is defined that a thickness of the bands of the first and second plated layers is Tp, a ratio (T1/Tp) between a thickness of the band of the first or second external electrode and a thickness of the band of the first or second plated layer may be equal to or more than 0.35.

"A value obtained by adding thicknesses of both bands of the first and second plated layers may be equal to or less than 25 .mu.m.

"According to another aspect of the present invention, there is provided a method for manufacturing a multilayer ceramic capacitor (MLCC), including: preparing a plurality of ceramic green sheets; alternately forming a plurality of first and second internal electrodes, exposed in mutually opposing directions, in a thickness direction by using a conductive paste on the respective ceramic green sheets; laminating the plurality of ceramic green sheets with the first and second internal electrodes formed thereon to form a laminate; firing the laminate to form a ceramic body; and forming first and second external electrodes on both end surfaces of the ceramic body such that the first and second external electrodes are in contact with exposed portions of the first and second internal electrodes so as to be electrically connected thereto, wherein when it is defined that a thickness of a band of the first and second external electrodes is T1 and a thickness of the ceramic body is T2, a ratio (T1/T2) of the thickness of the band of the first or second external electrode to the thickness of the ceramic body is equal to or less than 0.18.

"The first and second external electrodes may be formed according to a thermal transfer method.

BRIEF DESCRIPTION OF THE DRAWINGS

"The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

"FIG. 1 is a schematic perspective view of a multilayer ceramic capacitor (MLCC) according to an embodiment of the present invention;

"FIG. 2 is a front view schematically illustrating an MLCC according to an embodiment of the present invention;

"FIG. 3 is a cross-sectional view taken along line A-A' in FIG. 1;

"FIGS. 4A to 4D are plan views illustrating a process of forming external electrodes on both end surfaces of a ceramic body of an MLCC according to a thermal transfer method according to an embodiment of the present invention; and

"FIG. 5 is a cross-sectional view schematically illustrating a structure in which plated layers are added to the MLCC of FIG. 3."

For additional information on this patent application, see: KIM, Kyu Ree; LEE, Byoung Hwa; CHAE, Eun Hyuk; KIM, Doo Young. Multilayer Ceramic Capacitor and Method of Manufacturing the Same. Filed July 23, 2013 and posted July 10, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4733&p=95&f=G&l=50&d=PG01&S1=20140703.PD.&OS=PD/20140703&RS=PD/20140703

Keywords for this news article include: Samsung Electro-mechanics Co. Ltd.

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Source: Politics & Government Week


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