Patent ID: 12217914

DETAILED DESCRIPTION

Exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.

In the drawing, a first direction may be defined as a thickness (T) direction, a second direction may be defined as a length (L) direction, and a third direction may be defined as a width (W) direction.

Referring toFIGS.1to6, a ceramic electronic component100may include a body110including a dielectric layer111and a plurality of internal electrodes121and122stacked in a first direction with the dielectric layer therebetween and including first and second surfaces opposing each other in the first direction and side surfaces connected to the first and second surfaces, external electrodes131and132disposed on the side surface of the body110, and an insulating layer150covering surfaces of the external electrodes131and132and including a plurality of openings H1and H2exposing the external electrodes131and132, wherein a ratio of an area of the plurality of openings H1and H2to an area of the surfaces of the external electrodes131and132covered by the insulating layer15020% to 70%.

As described above, when an insulating layer is disposed on the lower surface to prevent an occurrence of cracks of the ceramic electronic component and improve bending strength, a conductive adhesive such as solder and the external electrode of the ceramic electronic component may not be connected through the lower surface of the ceramic electronic component, causing a problem in that adhesive strength between the ceramic electronic component and the PCB is lowered. In addition, since the conductive adhesive is connected only to the side surface of the external electrode due to the insulating layer formed on the lower surface of the ceramic electronic component, a length of a current path is increased, resulting in an increase in ESL.

Meanwhile, in the ceramic electronic component100according to an exemplary embodiment in the present disclosure, the insulating layer150is formed on the lower surface of the body110to improve bending strength, while the insulating layer150including a predetermined amount of the plurality of openings H1and H2exposes the external electrodes131and132, thereby improving adhesive strength and reducing ESL.

Hereinafter, each component included in the ceramic electronic component100according to an exemplary embodiment in the present disclosure will be described in more detail.

There is no particular limitation on a specific shape of the body110, but as shown, the body110may have a hexahedral shape or a shape similar thereto. During a firing process, due to the shrinkage of the ceramic powder included in the body110or the polishing of the corners, the body110may not have a perfectly straight hexahedral shape but may have a substantially hexahedral shape.

The body110may include first and second surfaces1and2opposing each other in the first direction and side surfaces connected to the first and second surfaces1and2, respectively. In this case, the side surfaces may include third and fourth surfaces3and4connected to the first and second surfaces and facing each other in the second direction and fifth and sixth surfaces5and6connected to the first to fourth surfaces and facing each other in the third direction.

In the body110, the dielectric layer111and the internal electrodes121and122may be alternately stacked. A plurality of dielectric layers111forming the body110are in a sintered state, and adjacent dielectric layers111may be integrated such that boundaries therebetween may not be readily apparent without using a scanning electron microscope (SEM).

The dielectric layer111may be formed by sintering a ceramic green sheet including ceramic powder, an organic solvent, and a binder. The ceramic powder is not particularly limited as long as sufficient capacitance may be obtained therewith. For example, a barium titanate-based (BaTiO3) material, a strontium titanate (SrTiO3)-based material, etc. may be used, but the present disclosure is not limited thereto.

At this time, a thickness of the dielectric layer111may be 10 μm or less in consideration of a size and capacitance of the body110, and may be preferably 0.6 μm or less, more preferably 0.4 μm or less for miniaturization and high capacitance of the ceramic electronic component100, but the present disclosure is not limited thereto.

Here, the thickness of the dielectric layer111may refer to an average thickness of the dielectric layer111disposed between the internal electrodes121and122. The average thickness of the dielectric layer111may be measured by scanning cross-sections of the body110in the first direction and the second direction with a scanning electron microscope having a magnification of 10,000. More specifically, the average value may be measured by measuring the thicknesses at a plurality of points of one dielectric layer111, for example, at 30 points equally spaced in the second direction. In addition, when the average value is measured by extending the measurement of the average value to the plurality of dielectric layers111, the average thickness of the dielectric layer111may be more generalized.

The body110may include a capacitance forming portion Ac forming capacitance by including a plurality of first internal electrodes121and a plurality of second internal electrodes122disposed to face each other with the dielectric layer111interposed therebetween, a first cover portion112disposed on an upper surface of the capacitance forming portion Ac and a second cover portion113disposed on a lower surface of the capacitance forming portion Ac. The first cover portion112and the second cover portion113may be formed by stacking a single dielectric layer or two or more dielectric layers on upper and lower surfaces of the capacitance forming portion Ac in the first direction, and may perform a function of basically preventing damage to the internal electrodes due to physical or chemical stress. The first and second cover portions112and113may have the same configuration as the dielectric layer111except that the first and second cover portions112and113do not include internal electrodes. Each of the first and second cover portions112and113may have a thickness of 20 μm or less, but the present disclosure is not limited thereto.

The body110may include margin portions114and115disposed on a side surface of the capacitance forming portion Ac in the third direction. The margin portions114and115may include a first margin portion114disposed on the fifth surface of the body110and a second margin portion115disposed on the sixth surface6of the body110. The margin portions114and115may refer to a region between both ends of the internal electrodes121and122and a boundary surface of the body110in a cross-section of the body110cut in the first direction and the third direction. The margin portions114and115may basically serve to prevent damage to the internal electrodes121and122due to physical or chemical stress. The margin portions114and115may include the same or different material from the dielectric layer111. The margin portions114and115may be formed by forming the internal electrodes by applying a conductive paste on the ceramic green sheet except for a portion in which the margin portion is to be formed. Alternatively, in order to suppress a step difference caused by the internal electrodes121and122, the body110may be cut after stacking such that the internal electrodes121and122are exposed to the fifth and sixth surfaces5and6of the body, a single dielectric layer or two or more dielectric layers may be stacked on both side surfaces of the capacitance forming portion Ac in the third direction to form the margin portions114and115. A thickness of the margin portions114and115may be 20 μm or less, but the present disclosure is not limited thereto.

The internal electrodes121and122may be alternately disposed with the dielectric layer111, and the plurality of first internal electrodes121and the plurality of second internal electrodes122may be disposed to face each other with the dielectric layer111interposed therebetween. That is, the first and second internal electrodes121and122are a pair of electrodes having different polarities and may be formed to be alternately exposed through the third and fourth surfaces3and4of the body110in the stacking direction of the dielectric layer111.

For example, each of the plurality of first internal electrodes121may be spaced apart from the fourth surface4and exposed through the third surface3. In addition, each of the plurality of second internal electrodes122may be spaced apart from the third surface3and exposed through the fourth surface4. The plurality of first internal electrodes121and the plurality of second internal electrodes122may be electrically separated from each other by the dielectric layer111disposed therebetween. The plurality of first internal electrodes121and the plurality of second internal electrodes122may be alternately stacked in the first direction, but are not limited thereto, and may be alternately stacked in the third direction.

The internal electrodes121and122may be formed by printing a conductive paste for internal electrodes including a conductive metal to have a predetermined thickness on a ceramic green sheet. When the ceramic green sheets on which the internal electrodes121and122are printed are alternately stacked and sintered, the capacitance forming portion Ac of the body110may be formed. As a method of printing the conductive paste for internal electrodes, a screen printing method or a gravure printing method may be used, but the present disclosure is not limited thereto.

The conductive metal included in the internal electrodes121and122may be one or more of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof, but the present disclosure is not limited thereto.

In this case, a thickness of the internal electrodes121and122may be 10 μm or less in consideration of a size and capacitance of the body110, and may be 0.6 μm or less, more preferably, 0.4 μm or less for miniaturization and high capacitance of the ceramic electronic component100, but the present disclosure is not limited thereto.

Here, a thickness of the internal electrodes121and122may refer to an average thickness of the internal electrodes121and122. The average thickness of the internal electrodes121and122may be measured by scanning cross-sections of the body110in the first direction and the second direction with a scanning electron microscope having a magnification of 10,000. More specifically, the average value may be measured by measuring the thicknesses at a plurality of points of one internal electrode, for example, at 30 points equally spaced in the second direction. In addition, when the average value is measured by extending the measurement of the average value to the plurality of internal electrodes, the average thickness of the internal electrodes may be further generalized.

The external electrodes131and132may include a first external electrode131connected to a plurality of first internal electrodes121and a second external electrode132connected to a plurality of second internal electrodes122, and the first external electrode131and the second external electrode132may be disposed on both side surfaces of the body110, for example, the third and fourth surfaces3and4opposing each other. In this case, the external electrodes131and132may partially extend to the first, second, fifth, and sixth surfaces1,2,5, and6of the body110, respectively.

From this point of view, the first external electrode131may include a first connection portion P1adisposed on the third surface3of the body110and a first band portion P1bextending from the first connection portion P1ato portions of the first, second, fifth, and sixth surfaces1,2,5, and6of the body110. Also, the second external electrode132may include a second connection portion P2adisposed on the fourth surface4of the body110and a second band portion P2bextending onto portions of the first, second, fifth, and sixth surfaces of the body110from the second connection portion P2a.

The external electrodes131and132may be formed of any material as long as they have electrical conductivity, such as metal, and specific materials may be determined in consideration of electrical characteristics and structural stability, and the external electrodes131and132may have a multilayer structure. For example, the external electrodes131and132may include first electrode layers131aand132adisposed on the body110, second electrode layers131band132bdisposed on the first electrode layers131aand132a, and third electrode layers131cand132cdisposed on the second electrode layers131band132b.

The first electrode layers131aand132amay be, for example, fired electrodes including a conductive metal and glass. The conductive metal included in the first electrode layers131aand132amay include copper (Cu), nickel (Ni), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), lead (Pb), and/or an alloy containing the same, and preferably, copper (Cu) and/or nickel (Ni), but is not limited thereto.

The first electrode layers131aand132amay be formed by dipping the third and fourth surfaces3and4of the body110in a conductive paste for external electrodes containing conductive metal and glass and then firing. Alternatively, the first electrode layers131aand132amay be formed by transferring a sheet including a conductive metal and glass.

The second electrode layers131band132bmay be, for example, resin-based electrodes including a conductive metal and a resin. As the conductive metal included in the second electrode layers131band132b, a material having excellent electrical conductivity may be used, but is not particularly limited. For example, the conductive metal may include copper (Cu), nickel (Ni), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), lead (Pb), and/or an alloy containing the same, and preferably, copper (Cu) and/or nickel (Ni), but is not limited thereto.

An insulating resin may be used as a resin included in the second electrode layers131band132b, and is not particularly limited. For example, the resin may include an epoxy resin, but is not limited thereto. The second electrode layers131band132bmay be formed by applying and curing a paste including a conductive metal and a resin.

The third electrode layers131cand132cmay improve mounting characteristics. A type of the third electrode layers131cand132cis not particularly limited and may be a plating layer including nickel (Ni), tin (Sn), palladium (Pd) and/or an alloy containing the same, and may be formed as a plurality of layers. The third electrode layers131cand132cmay be, for example, a nickel (Ni) plating layer or a tin (Sn) plating layer, or may have a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially formed. Also, the third electrode layers131cand132cmay include a plurality of nickel (Ni) plating layers and/or a plurality of tin (Sn) plating layers.

In the drawings, a structure in which the ceramic electronic component100has two external electrodes131and132is described, but the present disclosure is not limited thereto and the number or shape of the external electrodes131and132may be changed according to a shape of the internal electrodes121and122or for other purposes.

The insulating layer150may prevent an occurrence of cracks by preventing a stress inside the body110during mounting on a substrate, and may improve bending strength of the ceramic electronic component100. In addition, the insulating layer150may prevent penetration of external moisture, thereby improving moisture resistance reliability. In addition, even when a high voltage is applied, the insulating layer150may prevent electrical breakdown of surface to improve surface insulation.

The insulating layer150may cover the external electrodes131and132. For example, the insulating layer150may cover the first surface of the body110and cover the first and second external electrodes131and132extending onto a portion of the first surface1of the body110. For example, the insulating layer150may be disposed on the first surface1of the body110and may extend onto the first band portion P1bextending onto the first surface1of the body110and the second band portion P2bextending onto the first surface1of the body110.

The insulating layer150may include a plurality of openings H1and H2exposing the external electrodes131and132. More specifically, the insulating layer150may include a plurality of first openings H1exposing the first external electrode131and a plurality of second openings H2exposing the second external electrodes132.

The shapes of the openings H1and H2are not particularly limited. That is, although the cross-sections of the openings H1and H2are shown to be circular in the drawing, for example, they may have a shape such as a quadrangle, an oval, or a quadrangle with rounded corners, or may have an irregular shape. The openings H1and H2may be formed by, for example, irradiating a laser to the insulating layer150or may be formed through a photolithography process, but the present disclosure is not limited thereto.

In this case, a ratio of an area of the plurality of openings H1and H2to an area S of the surfaces of the external electrodes131and132covered by the insulating layer150may satisfy 20% to 70%. More specifically, the ratio of the area of the plurality of first openings H1to the area S of the surface of the first external electrode131covered by the insulating layer150may satisfy 20% to 70%, and the ratio of the area of the plurality of second openings H2to the area S of the surface of the second external electrode132covered by the insulating layer150may satisfy 20% to 70%.

Here, the area S of the surfaces of the external electrodes131and132covered by the insulating layer150may refer to the sum of the area in which the insulating layer150is disposed on the first external electrode131and the area of the plurality of first openings H1. Alternatively, the area S covered by the insulating layer150may refer to the sum of the area in which the insulating layer150is disposed on the second external electrode132and the area of the plurality of second openings H2.

As the ratio of the area of the plurality of openings H1and H2to the area S of the surfaces of the external electrodes131and132covered by the insulating layer150satisfies 20% to 70%, the bending strength of the ceramic electronic component100may be improved, and since the external electrodes131and132and the conductive adhesive are connected through the plurality of openings H1and H2during mounting, adhesive strength of the ceramic electronic component100during mounting may be improved and a length of a current path is reduced to improve ESL characteristics.

If the ratio of the area of the plurality of openings H1and H2to the area S of the surfaces of the external electrodes131and132covered by the insulating layer150is less than 20%, the bending strength may be improved, but the external electrodes131and132and the conductive adhesive may not be sufficiently connected to each other, so that the bending strength may be reduced.

If the ratio of the area of the plurality of openings H1and H2to the area S of the surfaces of the external electrodes131and132covered by the insulating layer150is greater than 70%, the external electrodes131and132and the conductive adhesive may be sufficiently connected through the openings H1and H2, thereby improving adhesive strength, but since the insulating layer150is not sufficiently formed on the surfaces of the external electrodes131and132, the bending strength may be lowered.

The insulating layer150may include a material having electrical insulating properties, and the material is not particularly limited. For example, the insulating layer150may include at least one of a resin or ceramics. For example, the insulating layer150may include a resin, ceramics, or a mixture thereof. The resin may include, for example, an epoxy resin, a silicone resin, a fluorine resin, a phenol resin, a urea resin, a melamine resin, and/or an unsaturated polyester resin, but is not limited thereto. Ceramics may include, but are not limited to, lead zirconate titanate, alumina, silica, silicon carbide, and/or magnesium oxide.

In an exemplary embodiment in the present disclosure, the ceramic electronic component100may further include an additional insulating layer160covering the second surface2of the body110and the first and second external electrodes extending onto portions of the second surface2of the body110. By further including the additional insulating layer160, the bending strength of the ceramic electronic component100may be more effectively improved. In this case, the additional insulating layer160may include a plurality of first openings H1exposing the first external electrode131and a plurality of second openings H2exposing the second external electrode132. In this manner, mounting convenience may be secured.

Referring toFIG.8, the ceramic electronic component100according to an exemplary embodiment in the present disclosure is mounted on electrode pads210and220of a PCB200through conductive adhesives310and320such as solder. In this case, the bending strength of the ceramic electronic component100may be improved through the insulating layer150, and as the external electrodes131and132are connected to the conductive adhesives310and320through the plurality of openings H1and H2, the fixing strength and ESL characteristics may be improved.

Example

The ceramic electronic component100including external electrodes131and132including first electrode layers131aand132awhich are fired electrodes including copper (Cu), second electrode layers132aand132bwhich are resin electrodes including copper (Cu), and third electrode layers131cand132cincluding a nickel (Ni) plating layer and a tin (Sn) plating layer was prepared.

Thereafter, the insulating layer150covering the first surface1of the body110and external electrodes131and132extending onto a portion of the first surface of the body110was formed, and then, a photolithography process was executed to form a plurality of openings H1and H2exposing the external electrodes131and132on the insulating layer150.

<Measurement of Area Ratio of Opening>

In order to measure the ratio of the area of the plurality of openings H1and H2to the area S of the surface of the external electrodes131and132covered by the insulating layer150, a lower surface of the ceramic electronic component100was imaged with a scanning electron microscope (SEM).

Thereafter, scanning electron microscope (SEM) images were analyzed through energy dispersive X-ray spectroscopy (EDS). Here, in the insulating layer150covering the external electrodes131and132, the region in which the insulating layer150is formed and the region in which the openings H1and H2are formed may be distinguished from each other due to a difference in components included in each region. This is because the insulating layer150includes ceramics and/or resin, and the third electrode layers131cand132cexposed through the openings H1and H2include a conductive metal. In addition, the region in which the insulating layer150is formed and the region in which the openings H1and H2are formed may be distinguished from each other by performing EDS analysis on a back scattered electron (BSE) image of the SEM, enabling relative contrast comparison. Other measurement methods and/or tools appreciated by one of ordinary skill in the art, even if not described in the present disclosure, may also be used.

Thereafter, the ratio of the area of the plurality of first openings H1to the area of the surface of the first external electrode131covered by the insulating layer150was measured. The area ratio may be obtained by converting the BSE image into an image in which contrast and color are relatively compared based on pixels and measuring an area of the region in which the insulating layer150is disposed and an area of the region in which the first openings H1are disposed through a program in the EDS.

The area covered of the surface of the first external electrode131by the insulating layer150is the sum of the area in which the insulating layer150is disposed on the first external electrode131and the area in which the plurality of first openings H1are disposed. Thereafter, a ratio of the area of the plurality of first openings H1to the area of the surface of the first external electrode131covered by the insulating layer150was measured. Similarly, a ratio of the area of the plurality of second openings H2to the area of the surface of the second external electrode132covered by the insulating layer150was measured. Thereafter, average values of the area ratio of the first openings H1and the area ratio of the second openings H2were measured from 30 sample chips for each sample number and then averaged and described in Table 1.

<Bending Strength and Adhesive Strength>

Bending strength was measured using a method of measuring bending strength through a piezoelectric effect. After the sample chips were mounted on the board with tin (Sn) solder, a distance from the center that is pressed during bending was set to 5 mm to see if cracks occur in the sample chips, and the number of sample chips in which cracks occurred among 60 sample chips for each sample number is listed in Table 1.

For the adhesive strength, after the sample chips were mounted on a substrate with tin (Sn) solder and then a force was applied in a direction parallel to the substrate, and a case in which a chip was damaged when the applied force was 18 N or less was determined as defective adhesive strength. Here, the number of sample chips in which defective adhesive strength occurred, among 30 sample chips for each sample number is described in Table 1.

TABLE 1Sample No.Area ratio (%)Bending strengthAdhesive strength1*00/6014/302*50/609/303*100/608/304*150/603/305200/600/306250/600/307300/600/308400/600/309500/600/3010600/600/3011650/600/3012700/600/3013*752/600/3014*803/600/30*is Comparative Example

Referring to Table 1, sample Nos. 5 to 12 showed that the ratio of the area of the plurality of openings to the area of the surface of the external electrode covered by the insulating layer satisfies 20% to 70%, so that both bending strength and adhesive strength are excellent.

Referring to sample Nos. 1* to 4*, it can be seen that the area ratio is less than 20% and the external electrode and the tin solder are not sufficiently connected, so that the adhesive strength is lowered. In addition, referring to sample Nos. 13* and 14*, it can be seen that the area ratio exceeds 70% and the insulating is not sufficiently formed, so that the bending strength is lowered.

As set forth above, as one of various effects of the present disclosure, cracks that may occur during substrate mounting may be prevented and a ceramic electronic component having excellent bending strength may be provided.

As one of various effects of the present disclosure, a ceramic electronic component having excellent adhesive strength to a substrate may be provided.

As one of various effects of the present disclosure, a ceramic electronic component having excellent ESL characteristics by reducing a length of a current path may be provided.

While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present disclosure as defined by the appended claims.