Preparation method of laminated ceramic capacitor and laminated ceramic capacitor

Abstract

The invention relates to the technical field of chip-type laminated ceramic capacitors, in particular to a preparation method of a laminated ceramic capacitor and the laminated ceramic capacitor. The method comprises the following steps of: firstly, obtaining a laminated part which is formed after sintering and is exposed on the side surface of an internal electrode, and then manufacturing an insulating layer covering the end part at the end part of the laminated part. When the width range of the main surface covering part and the end surface covering part of the insulating layer is 20 [mu] m-100 [mu] m, the comprehensive performance of the laminated ceramic capacitor is better. If the width is smaller than 20 microns, when a covering layer is formed on the surface of the external electrode through an electroplating process subsequently, electroplating liquid easily enters the interior of the laminated ceramic capacitor from a gap between the main surface covering part and / or the end surface covering part and the laminated part, so that the insulation resistance of the laminated ceramic capacitor does not reach the standard; if the width is greater than 100 [mu] m, the contact area between the external electrode and the surface of the laminated part is insufficient, and the bonding strength between the external electrode and the surface of the laminated part is reduced, so that the external electrode is easier to peel off from the surface of the laminated part.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of multilayer ceramic capacitors, and in particular to a preparation method and a multilayer ceramic capacitor of a multilayer ceramic capacitor. Background Art

[0002] Generally, in order to manufacture a multilayer ceramic capacitor, a process of alternately laminating a first green ceramic sheet provided with a first internal electrode and a second green ceramic sheet provided with a second internal electrode in multiple layers is required. Through this lamination process, an unprocessed component body is obtained; the relatively arranged first end face and second end face of the unprocessed component body expose the internal electrodes, while the relatively arranged first side face and second side face of the unprocessed component body do not expose the internal electrodes. The unprocessed component body directly obtains the component body after sintering, and the insulating layers on the first side face and the second side face of the component body are formed by the two side edges of the first green ceramic sheet and the second green ceramic sheet in the unprocessed component body after sintering; the first internal electrode and the second internal electrode respectively led out from the first end face and the second end face are electrically connected to the first external electrode and the second external electrode respectively to form a multilayer ceramic capacitor.

[0003] In recent years, with the development of high density of electronic circuits in digital electronic devices such as mobile phones, the requirement for miniaturization of electronic components has become higher and higher, and higher requirements have been put forward for the miniaturization and large capacitance of multilayer ceramic capacitors constituting the electronic circuit. Summary of the Invention

[0004] The embodiments of the present application provide a preparation method and a multilayer ceramic capacitor of a multilayer ceramic capacitor, which can first obtain a laminated portion with the internal electrode exposed on the side after sintering, and then set an insulating layer on the side, which is beneficial to realizing the miniaturization and large capacitance of the multilayer ceramic capacitor.

[0005] In a first aspect of the present application, a method for manufacturing a multilayer ceramic capacitor is provided. The multilayer ceramic capacitor includes a stacked portion, and the stacked portion includes two main surfaces, two side surfaces, and two end surfaces that are respectively opposed to each other. The stacked portion further includes a plurality of internal electrode layers and a plurality of ceramic sintered layers. Each of the internal electrode layers and each of the ceramic sintered layers are alternately stacked along the longitudinal direction of the main surface, and each of the internal electrodes among the plurality of internal electrodes is exposed on the side surface; the method includes: obtaining the stacked portion; manufacturing an insulating layer covering the end portion at the end portion of the stacked portion, the insulating layer being a glass film integrally sintered and formed, and the insulating layer including a side surface covering portion, a main surface covering portion, and an end surface covering portion; manufacturing an external electrode on the end surface to obtain the multilayer ceramic capacitor; wherein, the side surface covering portion is used to cover the entire area of the side surface, the main surface covering portion is used to cover the edge portion of one end of the main surface close to the side surface, the end surface covering portion is used to cover the edge portion of one end of the end surface close to the side surface, and the width range of the main surface covering portion and the end surface covering portion is 20 μm to 100 μm.

[0006] In an embodiment of the present application, first, a stacked portion with internal electrodes exposed on the side surface after sintering is obtained, and then an insulating layer covering the end portion is manufactured at the end portion of the stacked portion located on the side surface, which is beneficial to realizing the miniaturization and large capacity of the multilayer ceramic capacitor. In addition, the insulating layer includes a side surface covering portion, a main surface covering portion, and an end surface covering portion; when the width range of the main surface covering portion and the end surface covering portion is 20 μm to 100 μm, the comprehensive performance of the multilayer ceramic capacitor is better. If the width of the main surface covering portion and the end surface covering portion is less than 20 μm, when a covering layer is formed on the surface of the external electrode by an electroplating process subsequently, the electroplating solution is likely to enter the interior of the multilayer ceramic capacitor from the gap between the main surface covering portion and / or the end surface covering portion and the stacked portion, resulting in the insulation resistance of the multilayer ceramic capacitor not meeting the standard; if the width of the main surface covering portion and the end surface covering portion is greater than 100 μm, the contact area between the external electrode and the surface of the stacked portion is insufficient, reducing the bonding strength between the external electrode and the surface of the stacked portion, and making the external electrode relatively easy to peel off from the stacked portion.

[0007] In some embodiments, before manufacturing the glass insulating layer on the stacked portion, the method further includes: removing the ceramic sintered material covering the surface of each of the internal electrodes exposed on the side surface by a physical grinding method and / or an etching method.

[0008] In some embodiments, before manufacturing the insulating layer covering the end portion at the end portion of the stacked portion, the method further includes: etching the surface of each of the internal electrodes exposed on the side surface with an etching solution.

[0009] In some embodiments, after etching the surface of each of the plurality of internal electrodes exposed on the side surface using an etching solution, the method further includes: cleaning the etching solution adhering to the side surface using a cleaning agent.

[0010] In some embodiments, the insulating layer is a glass film. Fabricating the insulating layer covering the end portion of the stacked portion includes: after cleaning the etching solution adhering to the side surface using the cleaning agent, applying a glass paste on the side surface, and performing a drying process and a baking process on the glass paste so that the glass paste forms the glass film on the side surface.

[0011] In some embodiments, the pH value of the etching solution is not greater than 2.

[0012] In some embodiments, the depth of the internal electrode etched off on the surface by the etching solution does not exceed 1 μm.

[0013] In some embodiments, the widths of the main surface covering portion and the end surface covering portion are 50 μm.

[0014] In some embodiments, obtaining the stacked portion includes: laminating and pressing a plurality of ceramic green sheet master plates printed with internal electrode patterns to obtain a stacked portion green sheet master plate; cutting the stacked portion green sheet master plate to obtain a plurality of stacked portion green sheets of specified dimensions; sintering the stacked portion green sheets to obtain a stacked portion; wherein, the first cross-section and the second cross-section are surfaces formed by cutting the stacked portion green sheet master plate.

[0015] In a second aspect of the present application, there is also provided a multilayer ceramic capacitor, which is prepared by the method described in the first aspect.

[0016] It should be understood that the content described in the Summary of the Invention section is not intended to limit the key or important features of the present disclosure, nor to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments of the present invention. Obviously, the following described drawings are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 is a schematic structural diagram of a multilayer ceramic capacitor provided by some embodiments of the present application;

[0019] Figure 2Schematic structural diagram of an element body provided by some embodiments of the present application;

[0020] Figure 3 Schematic structural diagram of a stacked portion provided by some embodiments of the present application;

[0021] Figure 4 Schematic structural diagram of an existing first green ceramic sheet provided with a first internal electrode and a second green ceramic sheet provided with a second internal electrode;

[0022] Figure 5 Schematic flow chart of a method for manufacturing a multilayer ceramic capacitor provided by some embodiments of the present application;

[0023] Figure 6 Schematic structural diagram of a green body of a stacked portion provided by some embodiments of the present application;

[0024] Figure 7 Schematic structural diagram of a first green ceramic sheet provided with a first internal electrode and a second green ceramic sheet provided with a second internal electrode provided by some embodiments of the present application. Detailed implementation manners

[0025] The principles and spirit of the present disclosure will be described below with reference to several exemplary embodiments shown in the accompanying drawings. It should be understood that the description of these specific embodiments is only for enabling those skilled in the art to better understand and implement the present disclosure, and does not limit the scope of the present disclosure in any way. In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this disclosure pertains.

[0026] As used herein, the term "comprising" and its like shall be understood as an open inclusion, i.e., "including but not limited to". The term "based on" shall be understood as "at least partially based on". The term "one embodiment" or "the embodiment" shall be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects, and are only used to distinguish the objects referred to, without implying a specific spatial order, temporal order, order of importance, etc. of the objects referred to.

[0027] Figure 1 Schematic structural diagram of a multilayer ceramic capacitor (MLCC) provided by some embodiments of the present application. As Figure 1 shown, the MLCC includes a component body 10, a first external electrode 20, and a second external electrode 30; wherein, the first external electrode 20 and the second external electrode 30 are respectively disposed on two opposite end faces of the component body 10. Exemplarily, Figure 2The structural schematic diagram of the component main body 10 is shown, as Figure 2 shown. The component main body 10 includes a stacked portion 11 and a first insulating layer 12 and a second insulating layer 13 disposed on two opposite side surfaces of the stacked portion 11.

[0028] In Figure 1 and Figure 2 , although the respective boundaries between the stacked portion 11 and the first insulating layer 12 and the second insulating layer 13 are clearly shown, showing the boundaries is for the convenience of explanation; actually, such boundaries do not clearly appear.

[0029] Please refer to Figure 3 . The stacked portion 11 is in a cuboid shape or approximately cuboid shape. The stacked portion 11 includes two main surfaces, two side surfaces, and two end surfaces that are respectively opposed to each other; among them, the two end surfaces of the stacked portion 11 include a first end surface a1 and a second end surface (not shown in the figure) disposed opposite to the first end surface a1. The two side surfaces of the stacked portion 11 include a first side surface b1 and a second side surface (not shown in the figure) disposed opposite to the first side surface b1. The two main surfaces of the stacked portion 11 include a first main surface c1 and a second main surface (not shown in the figure) disposed opposite to the first main surface c1. The first insulating layer 12 and the second insulating layer 13 are respectively disposed at the ends of the first side surface b1 and the second side surface. The first external electrode 20 and the second external electrode 30 are respectively disposed on the first end surface a1 and the second end surface. The stacked portion 11 further includes a plurality of internal electrode layers (such as a plurality of first internal electrodes 111 and a plurality of second internal electrodes 112) and a plurality of ceramic sintered layers 113, and each internal electrode layer and each ceramic sintered layer are alternately stacked along the longitudinal direction of the main surface, and each internal electrode among the plurality of internal electrodes is exposed on both side surfaces.

[0030] Please refer to Figure 4 a and b in. In the prior art, in order to manufacture a multilayer ceramic capacitor, it is necessary to alternately place a first ceramic green sheet 42 provided with a first internal electrode 41 and a second ceramic green sheet 44 provided with a second internal electrode 43 in a multi-layer stacking process to obtain an unprocessed component main body; the unprocessed component main body is sintered to obtain the component main body 10 as shown in Figure 2 . In the prior art, in order to reduce the short-circuit phenomenon between the first internal electrode 41 and the second internal electrode 42 of the MLCC, a protection area (also called side gap) w is provided between the side edge of the first ceramic green sheet 42 and the side edge of the first internal electrode 41, and between the side edge of the second ceramic green sheet 44 and the side edge of the second internal electrode 43. The protection area w forms the first insulating layer and the second insulating layer of the component main body 10 after sintering respectively.

[0031] To achieve miniaturization and high capacitance of multilayer ceramic capacitors, embodiments of the present application obtain a stacked portion with internal electrodes exposed on the side after sintering, and then an insulating layer is provided on the side. To facilitate the reader's understanding of the present invention, specific embodiments will be described below.

[0032] Exemplarily, Figure 5 shows the process of the method for preparing a multilayer ceramic capacitor provided by an embodiment of the present application, and this method can be used to prepare Figure 1 the multilayer ceramic capacitor shown in, please refer to Figure 5 , and this method includes the following steps:

[0033] Step 51, obtain the stacked portion.

[0034] The stacked portion in the embodiment of the present application is obtained by sintering a green body of the stacked portion; wherein, the green body of the stacked portion includes a plurality of ceramic green sheets stacked along the longitudinal direction of the ceramic green sheet and internal electrodes arranged along the interfaces between adjacent ceramic green sheets. In some embodiments, step 51 specifically includes: laminating and pressing a plurality of ceramic green sheet master plates printed with internal electrode patterns to obtain a master plate of the green body of the stacked portion, cutting the master plate of the green body of the stacked portion to obtain a plurality of green bodies of the stacked portion with specified dimensions, and sintering the green bodies of the stacked portion to obtain the stacked portion; wherein, the first cross-section and the second cross-section are surfaces formed by cutting the master plate of the green body of the stacked portion. Since the first cross-section and the second cross-section are obtained by cutting the master plate, adhesion is likely to occur between adjacent internal electrodes exposed on the first cross-section and the second cross-section.

[0035] Exemplarily, Figure 6 shows a schematic structural diagram of the green body of the stacked portion. As Figure 6 shown, the green body 50 of the stacked portion is in a cuboid shape or approximately cuboid shape. The green body 50 of the stacked portion includes a first prefabricated end face A1 and a second prefabricated end face (not shown in the figure) arranged opposite to the first prefabricated end face A1. The green body 50 of the stacked portion further includes a first cross-section B1 and a second cross-section (not shown in the figure) arranged opposite to the first cross-section B1. In addition, the green body 50 of the stacked portion further includes a first prefabricated main face C1 and a second prefabricated main face arranged opposite to the first prefabricated main face C1.

[0036] Specifically, the internal electrodes in the green body 50 of the stacked portion include first internal electrodes 51 and second internal electrodes 52, and the first internal electrodes 51 and the second internal electrodes 52 are alternately arranged. Among them, the first prefabricated end face A1 exposes the first internal electrodes 51 but does not expose the second internal electrodes 52; the second prefabricated end face exposes the second internal electrodes 52 but does not expose the first internal electrodes 51; the first cross-section B1 and the second cross-section expose both the first internal electrodes 51 and the second internal electrodes 52 simultaneously.

[0037] Please refer to Figure 7Among a and b in it, the green sheet 50 of the stacked portion specifically includes a plurality of first ceramic green sheets 72 provided with first internal electrodes 71 and a plurality of second ceramic green sheets 74 provided with second internal electrodes 73, and the first ceramic green sheets and the second ceramic green sheets are alternately stacked to form a green sheet of the stacked portion as shown in Figure 6 Shown. Different from Figure 4 is that Figure 7 on both opposite side ends of the first ceramic green sheet 72 and the second ceramic green sheet 74 in

[0038] In this embodiment, since the stacked portion is obtained by sintering the green sheet of the stacked portion, the stacked portion and the green sheet of the stacked portion have corresponding structures. Please continue to refer to Figure 3 , after sintering the green sheet of the stacked portion, the first cross-section and the second cross-section of the green sheet of the stacked portion respectively form the first side surface a1 and the second side surface of the stacked portion 11, and the first side surface b1 and the second side surface simultaneously expose the first internal electrode 111 and the second internal electrode 112; and, the first prefabricated end surface and the second prefabricated end surface of the green sheet of the stacked portion respectively form the first end surface a1 and the second end surface of the stacked portion. The first end surface a1 only exposes the first internal electrode 111 and does not expose the second internal electrode, and the second end surface only exposes the second internal electrode 112 and does not expose the first internal electrode; at the same time, the first prefabricated main surface and the second prefabricated main surface of the green sheet of the stacked portion respectively form the first main surface c1 and the second main surface of the stacked portion. The ceramic green sheets in the green sheet of the stacked portion form ceramic sintered layers 113 after sintering. Therefore, the stacked portion 11 includes a plurality of ceramic sintered layers 113 extending in the direction of the first main surface c1 and stacked longitudinally with the first main surface and a plurality of pairs of first internal electrodes 111 and second internal electrodes 112 formed along the interfaces between the ceramic sintered layers 113. The first internal electrode 111 and the second internal electrode 112 are opposed to each other across the ceramic sintered layer 113, and electrical characteristics will appear based on this opposition to form a capacitance.

[0039] Step 52, fabricate an insulating layer covering the end of the stacked portion at the end.

[0040] In the embodiment of the present application, the two ends of the stacked portion include a first end and a second end. Insulating layers are provided at both ends. The insulating layer is an integrally sintered glass film. The insulating layer includes a side covering portion, a main surface covering portion, and an end surface covering portion; wherein, the side covering portion is used to cover the entire area of the side surface, the main surface covering portion is used to cover the edge portion of one end of the main surface close to the side surface, and the end surface covering portion is used to cover the edge portion of one end of the end surface close to the side surface.

[0041] Please continue to refer to Figure 2, the insulating layer includes a first insulating layer 12 disposed at the first end and a second insulating layer 13 disposed at the second end. Taking the second insulating layer 13 as an example for illustration. The second insulating layer 13 includes a side covering portion 131, two main surface covering portions 132, and two end surface covering portions 133; wherein, the side covering portion 131 is used to cover the entire area of the first side surface b1, the two end surface covering portions 133 are respectively used to cover the first end surface a1 and the edge portion of the second end surface near the first side surface b1, and the two main surface covering portions 132 are respectively used to cover the first main surface c1 and the edge portion of the second main surface near the first side surface b1. Wherein, the widths of the main surface covering portion 132 and the end surface covering portion 133 are d1 and d2 respectively, and the sizes of d1 and d2 can be the same or different.

[0042] In the embodiments of the present application, when the width ranges of the main surface covering portion and the end surface covering portion are 20μm to 100μm, the comprehensive performance of the multilayer ceramic capacitor is better. If the widths of the main surface covering portion and the end surface covering portion are less than 20μm, when forming a covering layer on the surface of the external electrode through an electroplating process subsequently, the electroplating solution is likely to enter the interior of the multilayer ceramic capacitor from the gap between the main surface covering portion and / or the end surface covering portion and the stacked portion, resulting in the insulation resistance of the multilayer ceramic capacitor not meeting the standard; if the widths of the main surface covering portion and the end surface covering portion are greater than 100μm, the contact area between the external electrode and the surface of the stacked portion is insufficient, affecting the bonding strength between the external electrode and the surface of the stacked portion, and making the external electrode easier to peel off from the component body.

[0043] In some embodiments, before step 52, the above method further includes: removing the ceramic sintered material covering the surface of each of the several internal electrodes exposed on the side by a physical grinding method and / or an etching method. Specifically, in certain embodiments of the present application, the physical grinding method specifically includes a drum grinding method and / or a polishing grinding method, etc. The etching method is specifically to chemically etch the ceramic sintered material covering the surface of each internal electrode with a ceramic etching solution such as hydrofluoric acid and / or phosphoric acid.

[0044] In some embodiments, after removing the ceramic sintered material covering the surface of each of the several internal electrodes exposed on the side and before step 52, the above method further includes: etching the surface of each of the several internal electrodes exposed on the side with an etching solution.

[0045] In some embodiments, due to the easy occurrence of adhesion between adjacent internal electrodes exposed on the first cross-section and the second cross-section, there is also adhesion between adjacent internal electrodes exposed on the first side surface and the second side surface respectively formed after sintering of the first cross-section and the second cross-section, which may cause short circuit of the internal electrodes. Therefore, in order to improve the adhesion between adjacent internal electrodes exposed on the first side surface and the second side surface, in this embodiment, an etching solution is used to etch the internal electrodes exposed on the first side surface and the second side surface.

[0046] In some embodiments, the conductive material for the internal electrodes includes at least one of nickel (Ni), copper (Cu), silver (Ag), palladium (Pd), Ag-Pd alloy, and gold (Au).

[0047] For example, in some embodiments, when the internal electrode is a nickel electrode, the performance of the MLCC is better. At the same time, in order to further improve the etching effect and better improve the short-circuit phenomenon between the internal electrodes, the etching solution includes at least one of solutions such as ferrous chloride solution, nitric acid, sulfuric acid, and phosphoric acid.

[0048] In some embodiments, when the pH value of the etching solution is not greater than 2, the etching effect of the etching solution is better.

[0049] In some embodiments, the depth of the first internal electrode and the second internal electrode etched away by the etching treatment does not exceed 1 μm. If the etching depth exceeds 1 μm, the area of the internal electrode will be reduced, which is not conducive to improving the capacitance of the capacitor.

[0050] In some embodiments, after using the etching solution to etch the surface of each of the several internal electrodes exposed on the side surface, the method further includes: using a cleaner to clean the etching solution adhering to the side surface. Wherein, the side surface includes the first side surface and / or the second side surface. The cleaner can specifically be any suitable cleaner such as water and / or dry ice. For example, the side surface with the adhering etching solution can be immersed in water, and an ultrasonic cleaning process can be used to clean the etching solution adhering to the side surface.

[0051] In some embodiments, step 52 specifically includes: after using the cleaner to clean the etching solution adhering to the side surface, applying glass paste on the side surface, and performing a drying treatment and a baking treatment on the glass paste so that the glass paste forms a glass film on the side surface. The glass film is also the insulating layer. Specifically, in certain embodiments of the present application, the glass paste can be applied on the washed side surface by the Dipping method and the Blotting method.

[0052] Step 53, fabricate an external electrode on the end face to obtain a multilayer ceramic capacitor.

[0053] In some embodiments, after an insulating layer is disposed on the side surface, an external electrode is disposed on the end surface to obtain the multilayer ceramic capacitor. The external electrode includes a first external electrode disposed on a first end surface and a second external electrode disposed on a second end surface. In the embodiments of the present application, the first internal electrode has an exposed end exposed at the first end surface, and the second internal electrode has an exposed end exposed at the second end surface. After the first external electrode and the second external electrode are respectively disposed on the first end surface and the second end surface, the first internal electrode exposed at the first end surface is electrically connected to the first external electrode, and the second internal electrode exposed at the second end surface is electrically connected to the second external electrode, forming a multilayer ceramic capacitor.

[0054] In some embodiments, after an external electrode is fabricated on the end surface, a coating may also be formed on the surface of the external electrode by electroplating to form a covering layer on the surface of the external electrode.

[0055] The embodiments of the present application also provide a multilayer ceramic capacitor, which is prepared according to the method provided in the above embodiments.

[0056] Several embodiments of the present application are provided below.

[0057] Embodiment 1

[0058] First, an insulating layer covering the end portion of the stacked portion is covered on the end portion, wherein the insulating layer is an integrally sintered glass film, and the insulating layer includes a side covering portion, a main surface covering portion, and an end surface covering portion.

[0059] Secondly, an external electrode is fabricated on the end surface, and a covering layer is fabricated on the surface of the external electrode by electroplating to obtain a multilayer ceramic capacitor; wherein, the side covering portion is used to cover the entire area of the side surface, the main surface covering portion is used to cover the edge portion of one end of the main surface close to the side surface, the end surface covering portion is used to cover the edge portion of one end of the end surface close to the side surface, and the widths of the main surface covering portion and the end surface covering portion are 50 μm.

[0060] Embodiment 2

[0061] The difference between this embodiment and Embodiment 1 is that the widths of the main surface covering portion and the end surface covering portion are 20 μm.

[0062] Embodiment 3

[0063] The difference between this embodiment and Embodiment 1 is that the widths of the main surface covering portion and the end surface covering portion are 100 μm.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Embodiment 1 is that the widths of the main surface covering portion and the end surface covering portion are 15 μm.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 1 is that the widths of the main surface covering portion and the end surface covering portion are 105 μm.

[0068] In the above embodiments and comparative examples, the thickness of the dielectric layer (i.e., the ceramic sintered layer) between the first internal electrode and the second internal electrode is 1.0 μm, the thicknesses of the first internal electrode and the second internal electrode are 1.0 μm, the size model of the multilayer ceramic capacitor is 1005 type, and the number of stacked layers is 250 layers. Insulation resistance (IR) characterization and external electrode peeling performance tests were respectively carried out on the MLCCs provided in Examples 1-3 and Comparative Examples 1-2, and the test results are shown in Table 1:

[0069] Table 1

[0070] IR defective rate External electrode peeling defective rate Example 1 0％ 0％ Example 2 0％ 0％ Example 3 0％ 0％ Comparative Example 1 25％ 0％ Comparative Example 2 0％ 20％

[0071] From the test results in Table 1, it can be seen that the IR failure rates and external electrode peeling failure rates of the MLCCs provided in Examples 1-3 are both 0%. The IR failure rate and external electrode peeling failure rate of the MLCC provided in Comparative Example 1 are 25% and 0% respectively. The IR failure rate and external electrode peeling failure rate of the MLCC provided in Comparative Example 2 are 0% and 20% respectively.

[0072] The reason for the IR failure of the MLCC provided in Comparative Example 1 is that the widths of the main surface covering portion and the end surface covering portion of the glass film are too small, resulting in insufficient bonding between the main surface covering portion and the end surface covering portion and the stacked portion. Therefore, during the electroplating process of the external electrode, the electroplating solution enters the inside of the stacked portion from the gap between the main surface covering portion and the end surface covering portion and the stacked portion, reducing the insulation performance inside the stacked portion.

[0073] The reason for the external electrode peeling failure of the MLCC provided in Comparative Example 2 is that the widths of the main surface covering portion and the end surface covering portion of the glass film are too large, resulting in a smaller contact area between the external electrode and the ceramic sintered layer on the end surface of the stacked portion, and reducing the bonding strength between the external electrode and the end surface of the stacked portion.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above. For the sake of brevity, they are not provided in detail; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a multilayer ceramic capacitor, characterized in that, The stacked ceramic capacitor includes a stacked portion, the stacked portion includes two main surfaces, two side surfaces, and two end surfaces that are respectively opposed to each other, the stacked portion further includes a plurality of internal electrode layers and a plurality of ceramic sintered layers, each of the internal electrode layers and each of the ceramic sintered layers are alternately stacked along the longitudinal direction of the main surface, and each of the internal electrodes among the plurality of internal electrodes is exposed on the side surface; The method includes: Obtaining the stacked portion; Manufacturing an insulating layer covering the end portion at the end portion of the stacked portion, the insulating layer is a glass film integrally sintered and formed, and the insulating layer includes a side surface covering portion, a main surface covering portion, and an end surface covering portion; Manufacturing an external electrode on the end surface to obtain the stacked ceramic capacitor; Wherein, the side surface covering portion is used to cover the entire area of the side surface, the main surface covering portion is used to cover the edge portion of one end of the main surface close to the side surface, the end surface covering portion is used to cover the edge portion of one end of the end surface close to the side surface, and the width range of the main surface covering portion and the end surface covering portion is 20 μm to 100 μm.

2. The method according to claim 1, wherein Before manufacturing the insulating layer covering the end portion at the end portion of the stacked portion, the method further includes: Removing the ceramic sintered material covering the surface of each of the internal electrodes exposed on the side surface by physical grinding method and / or etching method.

3. The method according to claim 1, wherein Before manufacturing the glass insulating layer on the stacked portion, the method further includes: Etching the surface of each of the internal electrodes exposed on the side surface with an etching solution.

4. The method according to claim 2, wherein After etching the surface of each of the internal electrodes exposed on the side surface with the etching solution, the method further includes: Cleaning the etching solution adhering to the side surface with a cleaning agent.

5. The method according to claim 4, wherein The insulating layer is a glass film, and manufacturing the insulating layer covering the end portion at the end portion of the stacked portion includes: After cleaning the etching solution adhering to the side surface with the cleaning agent, applying glass paste on the side surface, and performing a drying process and a baking process on the glass paste so that the glass paste forms the glass film on the side surface.

6. The method according to claim 3, wherein The pH value of the etching solution is not greater than 2.

7. The method according to claim 3, characterized in that The depth of the internal electrode etched off on the surface by the etching solution does not exceed 1 μm.

8. The method according to any one of claims 1-7, characterized in that, The widths of the main surface covering portion and the end surface covering portion are 50 μm.

9. The method according to any one of claims 1-7, characterized in that, Obtaining the stacked portion includes: Stacking and pressing a plurality of green ceramic sheets printed with internal electrode patterns to obtain a green master plate of the stacked portion; Cutting the green master plate of the stacked portion to obtain a plurality of green blanks of the stacked portion with specified dimensions; Performing a sintering process on the green blank of the stacked portion to obtain the stacked portion; Wherein, the first cross-section and the second cross-section are surfaces formed by cutting the green master plate of the stacked portion.

10. A multilayer ceramic capacitor, characterized in that, The stacked ceramic capacitor is prepared by the method according to any one of claims 1-9.

Images