Multi-layer ceramic capacitor and manufacturing method thereof

Abstract

A multilayer ceramic capacitor comprises a multilayer ceramic brick and first and second terminal electrodes. The multilayer ceramic brick has first and second end faces located opposite each other. The multilayer ceramic brick comprises a dielectric layer and an internal electrode layer. The dielectric layer comprises a perovskite oxide containing barium and titanium. The internal electrode layer is stacked alternately with the dielectric layer. Each internal electrode layer comprises an inner layer and a first indium separator layer. The material of the inner layer comprises nickel. The first indium separator layer is located between the inner layer and one of the dielectric layers. The first terminal electrode is positioned on the first end face and is electrically connected to one part of the internal electrode layer. The second terminal electrode is positioned on the second end face and is electrically connected to another part of the internal electrode layer.

Description

Technology Field

[0001] The present invention relates to capacitor manufacturing technology, and more specifically to multi-layer ceramic capacitors (MLCC). Background Technology

[0002] Multilayer ceramic capacitors are a type of ceramic capacitor whose capacitance is primarily proportional to the surface area of ​​the product and the number of stacked ceramic films. Multilayer ceramic capacitors can be directly mounted using Surface Mount Technology (SMT), and because they are easy to form into chips and have a small volume, they have become a mainstream product in the capacitor industry and are being applied to various electronic devices.

[0003] Perovskite oxide compounds are widely used in multilayer ceramic capacitors because using them as dielectric layer materials can reduce the cost of multilayer ceramic capacitors and improve their performance. However, as the number of internal electrode layers stacked in multilayer ceramic capacitors increases, the thickness of the dielectric layer decreases, which lowers the insulation resistance between the internal electrode layers, thereby reducing the reliability and high temperature load life of the multilayer ceramic capacitor.

[0004] In addition, as the thickness of the dielectric layer increases, the mean time to failure (MTTF) of the existing multilayer ceramic capacitor decreases, and the lifespan of the multilayer ceramic capacitor decreases.

[0005] Therefore, capacitor manufacturing technology capable of overcoming the shortcomings of existing multilayer ceramic capacitors is required. Prior art literature

[65535] Japanese Patent Publication No. JP 2023-132182 (September 22, 2023) Japanese Patent Publication No. JP 2023-135370 (September 28, 2023)

[0006] Accordingly, one objective of the present invention is to provide a multilayer ceramic capacitor in which each internal electrode layer comprises a nickel internal layer and an indium segregation layer between the nickel internal layer and the dielectric layer. The indium segregation layer can provide a Schottky barrier between the nickel internal layer and the dielectric layer, and the Schottky barrier can suppress leakage current. In addition, by adding indium metal, the multilayer ceramic brick can be sintered in a high-reducing atmosphere, thereby enabling the multilayer ceramic capacitor to have stable reliability even at higher operating temperatures, which can extend the high-temperature load life of the multilayer ceramic capacitor and improve the reliability of the multilayer ceramic capacitor. Compared to conventional multilayer ceramic capacitors, the MTTF of the multilayer ceramic capacitor according to the present invention is improved, thereby increasing the lifespan of the multilayer ceramic capacitor.

[0007] In accordance with the above-mentioned purpose, the present invention provides a multilayer ceramic capacitor. The multilayer ceramic capacitor comprises a multilayer ceramic brick, a first terminal electrode, and a second terminal electrode. The multilayer ceramic brick has a first end surface and a second end surface located opposite each other. The multilayer ceramic brick comprises a plurality of dielectric layers and a plurality of internal electrode layers. The dielectric layers comprise a plurality of perovskite oxides and borosilicate glass, and the perovskite oxides comprise barium and titanium. The internal electrode layers are stacked alternately with the dielectric layers. Each internal electrode layer comprises an inner layer and a first indium separator layer. The material of the inner layer comprises nickel. The first indium separator layer is located between the inner layer and one of the dielectric layers, and the thickness of the first indium separator layer is 1 nm to 19 nm, and the dielectric layer comprises a plurality of second indium separator layers each located at a plurality of grain boundaries of the perovskite oxide. The first terminal electrode is positioned on the first end surface and is electrically connected to a part of the internal electrode layer. The second terminal electrode is positioned on the second end surface and is electrically connected to another part of the internal electrode layer.

[0008] According to one embodiment of the present invention, when the total weight of the perovskite oxide is 100% by weight, the borosilicate glass accounts for 0.01% to 5% by weight.

[0009] According to one embodiment of the present invention, borosilicate glass comprises B2O3, Al2O3, and SiO2.

[0010] According to one embodiment of the present invention, the internal electrode layer is formed by sintering a nickel paste with added indium, and the nickel paste has 0.01 mol% to 5 mol% of indium added.

[0011] According to one embodiment of the present invention, the first indium content of the first indium separation layer is greater than the second indium content of each of the second indium separation layers.

[0012] According to one embodiment of the present invention, when the titanium content of the perovskite oxide and the second indium content of the second indium separation layers are set to 100 mol%, the second indium content is 10 -20 mole% to 10 -2 It accounts for a mole%.

[0013] According to one embodiment of the present invention, the first indium separation layer comprises indium, barium, and titanium.

[0014] According to one embodiment of the present invention, the second indium separation layer comprises indium, barium, and titanium.

[0015] According to one embodiment of the present invention, the thickness of each internal electrode layer is 0.4 to 0.6 times the thickness of each dielectric layer.

[0016] In accordance with the above-mentioned purpose, the present invention also provides a method for manufacturing a multilayer ceramic capacitor. The manufacturing method comprises the following steps: forming a plurality of dielectric layers in which the dielectric layer comprises a plurality of perovskite oxides and borosilicate glass, and the perovskite oxide comprises barium and titanium; forming a plurality of internal electrode layers; forming a laminated stack in which the internal electrode layers and the dielectric layers are alternately stacked; and performing a sintering process on the laminated stack to form a multilayer ceramic brick. The sintering process comprises the following steps: performing a low-temperature burn-out step and performing a high-temperature sintering step. forming a first terminal electrode and a second terminal electrode at each end of the multilayer ceramic brick to obtain a multilayer ceramic capacitor.

[0017] According to one embodiment of the present invention, when the total weight of the perovskite oxide is 100% by weight, the borosilicate glass accounts for 0.01% to 5% by weight.

[0018] According to one embodiment of the present invention, borosilicate glass comprises B2O3, Al2O3, and SiO2.

[0019] According to one embodiment of the present invention, the internal electrode layer comprises a nickel paste to which indium is added, and the nickel paste has 0.01 mol% to 5 mol% of indium added.

[0020] According to one embodiment of the present invention, after a sintering process, a first indium separation layer is formed at the interface between each internal electrode layer and each dielectric layer, and a plurality of second indium separation layers are formed at a plurality of grain boundaries of perovskite oxide, and the first indium separation layer and the second indium separation layers are formed simultaneously. Brief explanation of the drawing

[0021] Aspects of the invention are best understood from the following detailed description in conjunction with the accompanying drawings. It should be noted that, in accordance with standard industry practice, various features are not depicted in their actual proportions. In fact, the dimensions of various features may be increased or decreased at will for the sake of clarity of discussion. FIG. 1 is a schematic three-dimensional drawing of a multilayer ceramic capacitor according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view of a multilayer ceramic capacitor cut along the cross-sectional line AA of Figure 1. Figure 3 is a schematic cross-sectional view of a multilayer ceramic capacitor cut along the cross-sectional line BB of Figure 1. FIG. 4 is a flowchart illustrating a method for manufacturing a multilayer ceramic capacitor according to some embodiments of the present application. Figure 5 is a scanning transmission electron microscope (STEM) annular dark field (ADF) image of the multilayer ceramic capacitor of Experimental Example 1. Figure 6 is the In Lα energy dispersive X-ray mapping (EDX mapping) of Figure 5. Figure 7 is a scanning transmission electron microscope (STEM) bright-field image of the multilayer ceramic capacitor of Experimental Example 2. Figure 8 is the In Lα EDX mapping of Figure 7. Figure 9 is an enlarged view of the perovskite oxide (BaTiO3) of Figure 8. Figure 10 is the In Lα EDX mapping of Figure 9. Figure 11 is a diagram showing the relationship between the total dielectric layer thickness and MTTF in Ni-MLCC and Ni-In MLCC. Specific details for implementing the invention

[0022] Embodiments of the present invention are discussed in detail below. However, it should be recognized that the embodiments provide many applicable concepts that can be implemented in various specific contents. The embodiments discussed and disclosed are for illustrative purposes only and are not intended to limit the scope of the invention. All embodiments of the present invention disclose various different features, and these features may be implemented individually or in combination as desired.

[0023] Additionally, terms such as "first," "second," etc., used in this specification do not imply order or sequence, but are used merely to distinguish elements or operations described by the same technical term.

[0024] The spatial relationship between two elements described in this disclosure applies not only to directions illustrated in the drawings but also to directions not shown in the drawings, such as inversion directions. Furthermore, terms such as "connected" and "electrically connected" between two components mentioned in this disclosure are not limited to a direct connection or electrical connection between the two components, but may include an indirect connection or electrical connection as necessary.

[0025] In the present disclosure, an MLCC having a "metal" internal electrode layer is referred to as a "metal" MLCC, e.g., a Ni MLCC or a Ni-In MLCC. Specifically, "Ni MLCC" indicates an MLCC containing Ni in the internal electrode layer. Similarly, "Ni-In MLCC" indicates an MLCC containing Ni and In in the internal electrode layer.

[0026] Referring to FIGS. 1 to 3, FIGS. 1 to 3 each illustrate a schematic three-dimensional view of a multilayer ceramic capacitor (100) according to an embodiment of the present invention, and a schematic cross-sectional view of a multilayer ceramic capacitor (100) cut along cross-sectional line AA and cross-sectional line BB of FIG. 1. The multilayer ceramic capacitor (100) mainly comprises a multilayer ceramic brick (200), a first terminal electrode (300), and a second terminal electrode (400).

[0027] For example, the multilayer ceramic brick (200) may be a rectangular prism or a cube. However, the shape of the multilayer ceramic brick (200) may be designed to meet product requirements, and the invention is not limited thereto. The multilayer ceramic brick (200) has a first end face (202) and a second end face (204) that are opposite each other. In the example illustrated in FIGS. 1 to 3, the multilayer ceramic brick (200) is a rectangular prism, and the multilayer ceramic brick (200) further includes a first surface (205) and a second surface (206) that are opposite each other, and a third surface (207) and a fourth surface (208) that are opposite each other. The first end face (202), the second end face (204), the third surface (207), and the fourth surface (208) are all located between the first surface (205) and the second surface (206). The third surface (207) and the fourth surface (208) are located between the first end surface (202) and the second end surface (204).

[0028] A multilayer ceramic brick (200) may primarily comprise a plurality of dielectric layers (210) and a plurality of internal electrode layers (220). The dielectric layers (210) and the internal electrode layers (220) are stacked alternately. When manufacturing the multilayer ceramic brick (200), a green sheet of dielectric layer (210) and a slurry layer of internal electrode layer (220) may be stacked alternately, and then the stacked structure may be sintered. A dielectric layer (210) is a ceramic layer formed by sintering a green sheet of perovskite oxide and borosilicate glass, and each dielectric layer (210) comprises a plurality of perovskite oxides and borosilicate glass. Perovskite oxides include barium and titanium. In some examples, the dielectric layer (210) is made of barium titanate (BaTiO3) of perovskite oxide.

[0029] In some examples, the borosilicate glass comprises B2O3, Al2O3, and SiO2. In some examples, when the total weight of the perovskite oxide is 100 wt%, the borosilicate glass accounts for 0.01 wt% to 5 wt%, for example, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5 wt%. When the borosilicate glass is within the aforementioned range, the MTTF of the multilayer ceramic capacitor (100) can be improved, and accordingly, the lifespan of the multilayer ceramic capacitor (100) can be extended.

[0030] As illustrated in FIG. 2, the internal electrode layer (220) may be divided into two parts. One part of the internal electrode layer (220) extends from the first end surface (202) of the multilayer ceramic brick (200) toward the second end surface (204) and is spaced apart from the second end surface (204). The other part of the internal electrode layer (220) extends from the second end surface (204) toward the first end surface (202) and is spaced apart from the first end surface (202). The two parts of the internal electrode layer (220) are arranged alternately, and the dielectric layer (210) is located between the two adjacent internal electrode layers (220). The internal electrode layer (220) may be substantially parallel to the first surface (205) and the second surface (206) of the multilayer ceramic brick (200).

[0031] In the example illustrated in FIGS. 2 and 3, the internal electrode layer (220) each includes an inner layer (222) and a first indium separator layer (224). The material of the inner layer (222) includes nickel. For example, nickel may be a major component of the inner layer (222). The first indium separator layer (224) of each internal electrode layer (220) is located between the inner layer (222) and the dielectric layer (210) adjacent to the inner layer (222). Thus, the first indium separator layer (224) of each internal electrode layer (220) separates the inner layer (222) from the surrounding dielectric layer (210).

[0032] In some examples, the thickness of the first indium separator layer (224) is in the range of 1 nm to 100 nm, for example, 3, 5, 8, 10, 12, 15, 18, 19, 20, 30, 40, 50, 60, 70, 80, or 90 nm. When the thickness of the first indium separator layer (224) is within the aforementioned range, the MTTF of the multilayer ceramic capacitor (100) can be improved, and accordingly, the lifespan of the multilayer ceramic capacitor (100) can be increased. In some examples, referring to FIG. 2, the thickness h1 of each internal electrode layer is 0.4 to 0.6 times the thickness h2 of each dielectric layer. When the thickness ratio is within the aforementioned range, the MTTF of the multilayer ceramic capacitor (100) can be improved, and accordingly, the lifespan of the multilayer ceramic capacitor (100) can be increased. In some examples, referring to FIG. 2, the total thickness H of the dielectric layer (210) is in the range of 0.5 μm to 8.4 μm, e.g. 1.2, 3.2, 5, or 6.8 μm.

[0033] In some examples, the inner electrode layer (220) is formed by sintering a nickel paste to which indium is added. Thus, the first indium separation layer (224) may be an aggregated metallic phase layer of indium metal between the inner layer (222) composed of nickel and the ceramic body of the dielectric layer (210). In an example where the dielectric layer (210) is made of barium titanate, the first indium separation layer (224) may comprise indium, barium, and titanium. In some exemplary examples, 0.01 mol% to 5 mol% of indium, e.g., 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5 mol% of indium is added to the nickel paste. If the amount of indium added is within the range mentioned above, the MTTF of the multilayer ceramic capacitor (100) can be improved, and accordingly, the lifespan of the multilayer ceramic capacitor (100) can be increased.

[0034] By adding indium metal, the material of the inner electrode layer (220) can be sintered in a high-reducing atmosphere. For example, the material of the inner electrode layer (220) can be sintered in an atmosphere with a high hydrogen content. As a result, the multilayer ceramic capacitor (100) can exhibit stable reliability at higher operating temperatures such as 105°C and 125°C. Additionally, the first indium separator layer (224) can provide a Schottky barrier between the inner layer (222) and the dielectric layer (210), and the Schottky barrier can suppress leakage current of the multilayer ceramic capacitor (100). Thus, the multilayer ceramic capacitor (100) has a long load life at high temperatures and high reliability.

[0035] Referring to FIG. 1, a first terminal electrode (300) is disposed on a first end surface (202) of at least a multilayer ceramic brick (200) and is electrically connected to an internal electrode layer (220) extending from the first end surface (202). A second terminal electrode (400) is disposed on a second end surface (204) of at least a multilayer ceramic brick (200) and is electrically connected to an internal electrode layer (220) extending from the second end surface (204). In the example illustrated in FIG. 1 and FIG. 2, the first terminal electrode (300) covers the first end surface (202) and a first surface (205), a second surface (206), a third surface (207), and a fourth surface (208) adjacent to the first end surface (202). The second terminal electrode (400) covers the second end surface (204) and the first surface (205), second surface (206), third surface (207) and fourth surface (208) adjacent to the second end surface (204).

[0036] The first terminal electrode (300) and the second terminal electrode (400) may each have a single-layer structure or a multi-layer structure. In some examples, the first terminal electrode (300) and the second terminal electrode (400) each have a structure in which three layers are sequentially stacked, and the material of the first layer may be copper, silver, or a silver-palladium alloy, the material of the second layer may be nickel, and the material of the third layer may be tin. The multi-layer ceramic capacitor of the present invention may be used in autonomous electric vehicle technology, but is not limited thereto.

[0037] FIG. 4 is a flowchart illustrating a method (M) for manufacturing a multilayer ceramic capacitor (100) according to a partial embodiment of the present application. Referring to FIG. 2 and FIG. 4, a plurality of dielectric layers (210) are formed as shown in step 410 of the manufacturing method (M). A plurality of internal electrode layers (220) are formed as shown in step 420 of the manufacturing method (M). The internal electrode layers (220) and the dielectric layers (210) are alternately stacked to form a stacked stack as shown in step 430 of the manufacturing method (M).

[0038] Next, continuing to refer to FIGS. 2 and FIGS. 4, a multilayer ceramic brick (200) is formed by performing a sintering process on a stacked stack as shown in step 440 of the manufacturing method (M). The sintering process includes performing a low-temperature burnout step and performing a high-temperature sintering step. For example, the temperature of the low-temperature burnout step is 300°C. For example, the temperature of the high-temperature sintering step is 1200°C.

[0039] Next, referring to FIGS. 2 and FIGS. 4, as shown in steps 450 and 460 of the manufacturing method (M), a first terminal electrode (300) and a second terminal electrode (400) are formed at both ends of a multilayer ceramic brick (200), respectively, to obtain a multilayer ceramic capacitor (100).

[0040] The following examples are used to illustrate the application of the present invention, but are not intended to limit the invention. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the invention.

[0041] Experimental Example 1

[0042] In Experimental Example 1, BaTiO3 perovskite powder was ball-milled with additives such as 3 mol% Dy2O3, 0.1 mol% MgO, and 0.03 wt% borosilicate glass powder. After uniform mixing and drying, the raw powder was milled with an organic solvent to obtain a raw slurry. The slurry was cast onto a plastic film and dried to obtain a green ceramic sheet. Ni paste containing 0.05 wt% In2O3 powder was uniformly mixed with the Ni paste using a 3-roller mixer and printed as an inner layer on the green sheet. Multiple Ni-printed sheets were stacked and cut to obtain a green Ni-In MLCC chip. After exhausting the organic binder at 300°C, the MLCC was 1×10 -13 It was calcined at 1200°C for 2 hours under an oxygen partial pressure of Pa, and then reoxidized at a low temperature. During the sintering process, In2O3 was converted to metallic In in a reducing atmosphere, forming a Ni-In alloy. Finally, it was heated at 780°C for 20 minutes to form a Cu terminal electrode.

[0043] Subsequently, a highly accelerated life test (HALT) was conducted at 140°C and 40V (a voltage four times higher than the rated voltage). Leakage current performance degradation was evaluated using 20 samples of each MLCC. The specific parameters and MTTF of Experimental Example 1 are shown in Table 1 below.

[0044]

[0045] FIG. 5 is a scanning transmission electron microscope (STEM) annular dark-field (ADF) image of the multilayer ceramic capacitor (100a) of Experimental Example 1. FIG. 6 is the In Lα energy-dispersive X-ray mapping (EDX mapping) of FIG. 5. In FIG. 5 and 6, the internal electrode layer (220) was formed by sintering a nickel paste with added indium. Thus, the multilayer ceramic capacitor (100a) may also be referred to as a Ni-In MLCC. The structure of the multilayer ceramic capacitor (100a) was substantially identical to the structure of the multilayer ceramic capacitor (100). The difference between the multilayer ceramic capacitors (100a, 100) was that, in addition to the first indium separator layer (224) of the internal electrode layer (220), the dielectric layer (210) of the multilayer ceramic capacitor (100a) included a plurality of second indium separator layers (214).

[0046] Specifically, as shown in FIGS. 5 and 6, the dielectric layer (210) comprises a plurality of perovskite oxides (212), and the second indium separation layer (214) is located at the grain boundaries (212a) of the perovskite oxides (212). That is, in this embodiment, the indium metal present in the material of the inner electrode layer (220) is not only separated at the interface between the inner layer (222) and the dielectric layer (210), but also diffuses into the dielectric layer (210) and is separated at the grain boundaries (212a) of the perovskite oxides (212) of the dielectric layer (210).

[0047] Referring to FIGS. 5 and 6, the particle (i.e., BaTiO3) can be understood as having a "core-shell structure," where the core region of the particle is BaTiO3, and the shell region of the particle is a grain boundary (212a) containing indium metal (i.e., a second indium separation layer (214)) and a first indium separation layer (224) containing indium metal. That is, the indium metal was separated in the shell region of the core-shell structure. Specifically, the diffused In (3) occupied the Ti (4) sites of the perovskite oxide (212) and acted as an acceptor capable of capturing free electrons generated by oxygen vacancy formation during the sintering process in a reducing atmosphere. Thus, when In is separated in the shell region of the core-shell structured BaTiO3 particle including the grain boundary, the resistivity increases and the leakage current decreases, thereby improving the MTTF of the multilayer ceramic capacitor (100a).

[0048] Ni could form a liquid phase with borosilicate glass at the interface between each internal electrode layer (220) and each dielectric layer (210) and then diffuse into the shell region of the core-shell structured BaTiO3 particles. In some examples, the co-doping of borosilicate glass increases proportionally as In is added to the Ni paste. In some examples, the first indium separation layer (224) and the second indium separation layer (214) work cooperatively according to the total thickness of the dielectric layer (210).

[0049] In some examples, the first indium content of the first indium separation layer (224) was greater than the second indium content of each of the second indium separation layers (214). In some examples, when the titanium content of the perovskite oxide (212) and the second indium content of the second indium separation layers (214) are set to 100 mol%, the second indium content is 10 -20 mole% to 10 -2 It accounted for mole%. In some examples, the second indium separation layer contained indium, barium, and titanium.

[0050] In some examples, after the aforementioned sintering process, a first indium separation layer (224) is formed at the interface between each internal electrode layer (220) and each dielectric layer (210), and a plurality of second indium separation layers (214) are formed at a plurality of grain boundaries (212a) of the perovskite oxide (212), and the first indium separation layer (224) and the second indium separation layer (214) are formed simultaneously.

[0051] Experimental Examples 2 to 6

[0052] The manufacturing method of the multilayer ceramic capacitor of Experimental Example 1 was similar to the manufacturing method of the multilayer ceramic capacitors of Experimental Examples 2 to 6. In Experimental Examples 2 to 6, the amount of In2O3 added varied depending on the total thickness of the dielectric layer of the multilayer ceramic capacitor. The amount of borosilicate glass powder added was basically proportional to the amount of In2O3 added to promote In diffusion at the grain boundaries of the dielectric layer.

[0053] Experimental Examples 7 to 14

[0054] The method of manufacturing the multilayer ceramic capacitor of Experimental Example 1 was similar to the method of manufacturing the multilayer ceramic capacitor of Experimental Examples 7 to 14. In Experimental Examples 7 to 14, the total thickness of the dielectric layer of the multilayer ceramic capacitor was the same, and the amount of borosilicate glass powder added was in the range of 0.01 wt% to 5 wt%, but the amount of In2O3 added was different.

[0055] Comparative Examples 1 and 2

[0056] The method of manufacturing the multilayer ceramic capacitor of Experimental Example 1 was similar to the method of manufacturing the multilayer ceramic capacitors of Comparative Examples 1 and 2. In Comparative Example 1, In2O3 was not added. In Comparative Example 2, borosilicate glass powder was not added.

[0057] FIG. 7 is a scanning transmission electron microscope (STEM) bright-field image of the multilayer ceramic capacitor (100b) of Experimental Example 2. FIG. 8 is the In Lα EDX mapping of FIG. 7. In FIG. 7 and FIG. 8, the multilayer ceramic capacitor (100b) was a Ni-In MLCC. As shown in FIG. 8, In separation (i.e., the first indium separation layer (224) and the second indium separation layer (214)) occurred at the interface between the inner layer (222) and the dielectric layer (210) and at the grain boundary (212a) of the perovskite oxide (212).

[0058] Figure 9 is an enlarged view of the perovskite oxide (BaTiO3) of Figure 8. Figure 10 is the In Lα EDX mapping of Figure 9. As shown in Figure 9, In ​​diffused and separated in the shell region of the core-shell structure. In occupied the Ti sites of BaTiO3, and due to the separation of In in the shell region including the grain boundaries, the acceptor function could be extended to the core region of the dielectric layer. As the thickness of the dielectric layer increased, the separation of In in the shell region was also effective.

[0059] The results of Table 1 showed that, compared to the MTTF of the multilayer ceramic capacitors of Comparative Examples 1 and 2, the MLCC with a specific amount of borosilicate glass powder and In2O3 added showed an improved MTTF.

[0060] FIG. 11 is a diagram (1100) showing the relationship between the total thickness of the dielectric layer and the MTTF in Ni-MLCC and Ni-In MLCC. As shown in FIG. 11, as the total thickness of the dielectric layer increases, the MTTF of the Ni-In MLCC increases, thereby increasing the lifespan of the Ni-In MLCC. In addition, the MTTF of the Ni-In MLCC was superior to that of the Ni MLCC.

[0061] According to the above-described embodiment, it can be seen that one advantage of the present invention is that the internal electrode layer of the multilayer ceramic capacitor comprises a nickel inner layer and an indium separator layer between the nickel inner layer and the dielectric layer. The indium separator layer can provide a Schottky barrier between the nickel inner layer and the dielectric layer, and the Schottky barrier can suppress leakage current. In addition, by adding indium metal, the multilayer ceramic brick can be sintered in a high-reducing atmosphere, so that the multilayer ceramic capacitor has stable reliability even at higher operating temperatures, thereby increasing the high-temperature load life of the multilayer ceramic capacitor and improving the reliability of the multilayer ceramic capacitor. Compared to conventional multilayer ceramic capacitors, the MTTF of the multilayer ceramic capacitor according to the present invention is improved, thereby increasing the lifespan of the multilayer ceramic capacitor.

[0062] Although the present invention has been disclosed through the above embodiments, it is not intended to limit the invention. Anyone skilled in the art may make various changes and modifications without departing from the spirit and scope of the invention. Accordingly, the scope of protection of the present invention should be defined only by the appended claims.

Claims

Claim 1 A multi-layer ceramic capacitor comprising: a multi-layer ceramic brick having a first end surface and a second end surface opposite each other; said multi-layer ceramic brick comprising: a plurality of dielectric layers comprising a plurality of perovskite oxides and borosilicate glass, wherein the perovskite oxide comprises barium and titanium; said dielectric layers; and a plurality of internal electrode layers alternately stacked with said dielectric layers, said dielectric layers comprising an internal layer, said internal layer comprising nickel. and a first indium segregation layer located between the inner layer and one of the dielectric layers, wherein the thickness of the first indium segregation layer is in the range of 1 nm to 19 nm, and the dielectric layers each include a plurality of second indium segregation layers located at a plurality of grain boundaries of the perovskite oxide; comprising a first terminal electrode disposed on the first end surface and electrically connected to a portion of the inner electrode layer; A multilayer ceramic capacitor comprising: a second terminal electrode disposed on the second end surface and electrically connected to another part of the inner electrode layer; wherein, when the total weight of the perovskite oxide is 100 wt%, the borosilicate glass accounts for 0.01 wt% to 5 wt%, the inner electrode layers are formed by sintering a nickel paste with added indium, the nickel paste has 0.01 mol% to 5 mol% of indium added, and the amount of the borosilicate glass increases in proportion to the amount of indium. Claim 2 A multilayer ceramic capacitor according to claim 1, wherein the borosilicate glass comprises B2O3, Al2O3, and SiO2. Claim 3 A multilayer ceramic capacitor according to claim 1, wherein the first indium content of the first indium separator layer is greater than the second indium content of each of the second indium separators. Claim 4 In claim 1, when the titanium content of the perovskite oxide and the second indium content of the second indium separation layers are set to 100 mol%, the second indium content is 10 -20 mole% to 10 -2 A multilayer ceramic capacitor that occupies a mole percentage. Claim 5 A multilayer ceramic capacitor according to claim 1, wherein the first indium separator comprises indium, barium, and titanium. Claim 6 A multilayer ceramic capacitor according to claim 1, wherein the second indium separator comprises indium, barium, and titanium. Claim 7 A multilayer ceramic capacitor according to claim 1, wherein the thickness of each of the internal electrode layers is 0.4 to 0.6 times the thickness of each of the dielectric layers. Claim 8 A method for manufacturing a multilayer ceramic capacitor comprises: a step of forming a plurality of dielectric layers comprising a plurality of perovskite oxides and borosilicate glass, wherein the perovskite oxide comprises barium and titanium; a step of forming a plurality of internal electrode layers; a step of alternately stacking the internal electrode layers and the dielectric layers to form a laminated stack; a step of performing a sintering process on the laminated stack to form a multilayer ceramic brick; and a step of forming a first terminal electrode and a second terminal electrode at each end of the multilayer ceramic brick to obtain the multilayer ceramic capacitor; wherein the sintering process comprises performing a low-temperature burn-out step. A method for manufacturing a multilayer ceramic capacitor comprising: performing a high-temperature sintering step; wherein, when the total weight of the perovskite oxide is 100 wt%, the borosilicate glass accounts for 0.01 wt% to 5 wt%, the internal electrode layers include a nickel paste with added indium, the nickel paste has 0.01 mol% to 5 mol% of indium added, the amount of the borosilicate glass increases in proportion to the amount of indium, and after the sintering process, a first indium separating layer is formed at the interface between each of the internal electrode layers and each of the dielectric layers, and a plurality of second indium separating layers are formed at a plurality of grain boundaries of the perovskite oxide, and the first indium separating layer and the second indium separating layer are produced simultaneously. Claim 9 A method for manufacturing a multilayer ceramic capacitor according to claim 8, wherein the borosilicate glass comprises B2O3, Al2O3, and SiO2. Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete

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