This application claims the priority of Korean Patent Application No. 10-2010-0032742 filed on Apr. 9, 2010, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a method of manufacturing a multilayer ceramic capacitor, and more particularly, to a method of manufacturing a multilayer ceramic capacitor that has high strength while being capable of implementing super high capacitance.
2. Description of the Related Art
In general, a multilayer ceramic capacitor includes a plurality of ceramic dielectric sheets, and internal electrodes inserted between the plurality of ceramic dielectric sheets. A multilayer ceramic capacitor is currently in widespread use as a capacitive component for a variety of electronic devices due to its small size, high capacitance and ease of mounting on a substrate.
To cope with the current trend toward smaller and multi-functional electronic products, chip components are being reduced in size while having more functions. In response, multilayer ceramic capacitors are required to be smaller while realizing higher capacitance.
In order to increase the capacitance of a multilayer ceramic capacitor, dielectric layers interleaved with internal electrodes need to have a small thickness. To manufacture such dielectric layers, a method of forming green sheets using slurry is generally being used; however, it is difficult to achieve super high capacitance through the use of this method due to the inherent limitations in decreasing the thickness of the dielectric layers.
Furthermore, a multilayer ceramic capacitor, according to the related art, may be limited in the number of stacks thereof, be susceptible to damage from a physical shock, and experience interlayer cracks caused by a temperature change when multiple layers are deposited on a single dielectric.
Therefore, the development of a multilayer ceramic capacitor, capable of implementing super high capacitance while having a stable breaking strength, needs to be developed.
An aspect of the present invention provides a method of manufacturing a multilayer ceramic capacitor having high strength while being capable of implementing super high capacitance.
According to an aspect of the present invention, there is provided a method of manufacturing a multilayer ceramic capacitor, the method including: forming a base dielectric layer; forming a unit ceramic capacitor by alternately depositing internal dielectric layers and internal electrode layers on a top surface of the base dielectric layer; and stacking another unit ceramic capacitor on the unit ceramic capacitor, wherein the number of unit ceramic capacitors being stacked is two or more.
The forming of the base dielectric layer may include forming a green sheet by using slurry formed of a dielectric material.
The forming of the unit ceramic capacitor may include performing deposition while moving a mask in a horizontal direction.
The mask may be aligned to a preset spot when the internal dielectric layer is deposited using a single mask. When the internal electrode layer is deposited, the mask may be moved from the preset spot to the left or right at a preset distance.
In the forming of the unit ceramic capacitor, the internal dielectric layer may have a particle size ranging from 1 nm to 30 nm, and a thickness ranging from 10 nm to 500 nm, and the internal electrode layer may have a particle size ranging from 1 nm to 5 nm, and a thickness ranging from 1 nm to 200 nm.
In the forming of the base dielectric layer, the base dielectric layer may have a particle size ranging from 150 nm to 300 nm and a thickness ranging from 1 um to 10 um.
The forming of the unit ceramic capacitor may be performed by using sputtering, pulsed laser deposition (PLD), e-beam evaporation, or thermal evaporation.
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:
Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Moreover, detailed descriptions related to well-known functions or configurations will be ruled out in order not to unnecessarily obscure subject matters of the present invention.
The same or equivalent elements are referred to by the same reference numerals throughout the specification.
It will be understood that when an element is referred to as being “connected to” another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly connected to” another element, there are no intervening elements present. In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” “comprising,” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.
Referring to
The base dielectric layer 10 serves as a base for depositing a plurality of internal dielectric layers and a plurality of internal electrode layers on the top surface thereof. The base dielectric layer 10 may have a considerable thickness in order to enhance the strength of a multilayer ceramic capacitor.
The base dielectric layer 10 may be processed by a method of forming a green sheet using slurry of a dielectric material such as BaTiO3.
In this case, a particle size of the dielectric material processed into the form of slurry may range about 150 nm to 300 nm, and the processed base dielectric layer 10 may range from about 1 um to 10 um.
The internal electrode layer 20 may have a very small thickness as it is formed by using a deposition method.
In detail, the deposition method may utilize a well-known vacuum deposition method such as sputtering, pulsed layer deposition (PLD), e-beam evaporation, thermal evaporation or the like.
The internal electrode layer 20, formed by the deposition method, may be made of nickel (Ni) or the like. Here, the material of the internal electrode layer 20 may have a particle size ranging from about 1 nm to 5 nm, and the thickness of the internal electrode layer 20 may range from about 1 nm to 200 nm.
By the use of the deposition method, the internal electrode layer 20 may have a very small thickness, which is advantageous in reducing the size of a multilayer ceramic capacitor.
According to this exemplary embodiment, the internal electrode layer 20 is formed directly on the top surface of the base dielectric layer 10. However, an internal dielectric layer may first be deposited on the top surface of the base dielectric layer 10, and the internal electrode layer 20 may be deposited thereon.
Since the internal dielectric layer 30 is also formed by a deposition method like the internal electrode layer 20 of
In detail, the deposition process may utilize a well-known vacuum deposition method such as sputtering, pulsed laser deposition (PLD), e-beam evaporation, thermal evaporation or the like.
The internal dielectric layer 30, formed by the deposition method, may be made of BaTiO3 or the like. The material of the internal dielectric layer 30 may have a particle size ranging from about 1 nm to 30 nm, and the thickness of the internal dielectric layer 30 may range from about 10 nm to 500 nm.
By forming the internal dielectric layer 30, the internal dielectric layer 30 may have a very small thickness, thereby allowing for the implementation of super high capacitance.
This thin internal dielectric layer 30 may also be advantageous in reducing the size of the multilayer ceramic capacitor.
Such inner electrode layers 20 and inner dielectric layers 30 are alternately deposited on the top surface of the base dielectric layer 10, thereby manufacturing a unit ceramic capacitor.
According to this exemplary embodiment, the unit ceramic capacitor is illustrated as having two internal electrode layers 20 and two internal dielectric layers 30. However, the number of internal electrode layers 20 and the number of internal dielectric layers 30 may be changed freely as the occasion arises.
By stacking a plurality of unit ceramic capacitors, the strength of the multilayer ceramic capacitor can be enhanced.
The internal dielectric layers 30, formed by deposition, may allow for the implementation of high capacitance. Furthermore, as a stack is formed to include two or more base dielectric layers 10, high strength can be obtained.
In addition, the base dielectric layer 10 may contribute not only to the strength of the multilayer ceramic capacitor but also to capacitance in part.
According to this exemplary embodiment, two unit ceramic capacitors are stacked. However, the number of unit ceramic capacitors may be changed freely according to need.
Referring to
In this state, the internal dielectric layer 30 may be deposited through the opening s52 of the mask 50.
In this case, the mask 50 may be moved in a horizontal direction such that the center C2 of the one side of the mask 50 is placed at the center C1 of the corresponding one side of the base dielectric layer 10.
Although not shown in the drawing, the mask 50 is horizontally moved in a direction opposite to that of
Referring to
As set forth above, according to exemplary embodiments of the invention, the method of manufacturing a multilayer ceramic capacitor adopts a method of depositing dielectric layers and internal electrode layers on a base dielectric layer having a considerable thickness. Accordingly, very thin dielectric layers and internal electrode layers can be obtained, thereby allowing for the implementation of super high capacitance.
Furthermore, high breaking strength can be obtained by stacking two or more base dielectric layers, each of which has dielectric layers and internal electrodes layers deposited thereon.
While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.
Number | Date | Country | Kind |
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10-2010-0032742 | Apr 2010 | KR | national |