TWI752895B - Method for manufacturing multi-layer ceramic capacitor - Google Patents

Abstract

A method for manufacturing multi-layer ceramic capacitors is described. In this method, first ceramic blanks and second ceramic blanks are formed. First inner electrode layers and second inner electrode layers are respectively formed on surfaces of the first ceramic blanks and the second ceramic blanks. The first ceramic blanks and the second ceramic blanks are alternatively stacked and pressed to form a multi-layer body. The multi-layer body is cut into various multi-layer structures. The multi-layer structure includes first ceramic blank units and second ceramic blank units, which are alternatively stacked. The multi-layer structure has a first end surface and a second end surface, which are opposite to each other. A tumbling treatment is performed on the multi-layer structure. A first terminal electrode film and a second terminal electrode film are formed to respectively cover the first end surface and the second end surface. A sintering treatment is performed on the multi-layer structure to make the multi-layer structure form a multi-layer ceramic body, and to make the first terminal electrode film and the second terminal electrode film respectively form a first terminal electrode and a second terminal electrode. A first plating layer and a second plating layer are respectively formed on the first terminal electrode and the second terminal electrode.

Description

Manufacturing method of multilayer ceramic capacitor

The present disclosure relates to a capacitor manufacturing technology, and more particularly, to a method for manufacturing a multilayer ceramic capacitor (MLCC).

Multilayer ceramic capacitors are a type of ceramic capacitors, and their capacitance is mainly proportional to the surface area of the product and the number of stacked layers of ceramic films. Because MLCCs can be directly attached through surface mount technology (SMT), and MLCCs are easy to chip and small in size, they have now become mainstream products in the capacitor industry.

In the production of multilayer ceramic capacitors, the internal electrodes are generally first printed on the ceramic blank film, and then the ceramic diaphragms printed with the internal electrodes are stacked in a dislocation manner and then compressed into a multilayer ceramic body. Next, the laminated ceramic body is cut into laminated structures having desired product dimensions, and these laminated structures are sintered. Next, a tumbling process is performed on the laminated structure after sintering. Then, the terminal electrodes are dipping (dipping) treatment, and then sintered (curing) in a sintering furnace, so that the terminal electrodes are closely attached to both ends of the ceramic sheet. Then, follow-up terminal electrode plating treatment, testing, and product packaging are performed.

One of the objectives of the present disclosure is to provide a method for manufacturing a multilayer ceramic capacitor, which firstly guides the multilayer structure, and then the ceramic body and the metal terminal electrodes of the multilayer structure are densely formed at the same time during sintering. In the method of re-chamfering, the method of the present disclosure can avoid the mechanical stress of the bevel on the dense ceramic body and the stress generated by the temperature change of the sintered terminal electrode.

Another object of the present disclosure is to provide a method for manufacturing a multilayer ceramic capacitor, which sinters the ceramic body and the metal terminal electrodes together, thereby omitting the terminal electrode sintering process, thereby simplifying the process and shortening the process time. This can increase productivity.

In accordance with the above objective of the present disclosure, a method for manufacturing a multilayer ceramic capacitor is provided. In this method, a plurality of first ceramic green sheets and a plurality of second ceramic green sheets are prepared. A plurality of first internal electrode layers are formed on a surface of each of the first ceramic green sheets, and a plurality of second internal electrode layers are formed on a surface of each of the second ceramic green sheets. The first ceramic green sheets and the second ceramic green sheets are interleaved and laminated to form a laminate. The layered body is cut to form a plurality of layered structures. Each laminated structure includes a plurality of first ceramic green sheet units and a plurality of second ceramic green sheet units that are alternately stacked. Each first ceramic green unit includes a first internal electrode layer, and each second ceramic green unit includes a second internal electrode layer. Each laminated structure has a first end face and a second end face opposite to each other. The first internal electrode layer extends to the first end face, and the second internal electrode layer extends to the second end face. The adjacent first internal electrode layers are physically separated from the second internal electrode layers. Chamfering is performed on each laminated structure. A plurality of first terminal electrode films are formed to respectively cover the first end surfaces of the laminated structure, and a plurality of second terminal electrode films are formed to respectively cover the second end surfaces of the laminated structure. After the first terminal electrode film and the second terminal electrode film are formed, these laminated structures are sintered, so that each laminated structure forms a laminated ceramic body, and the first terminal electrode films respectively form a plurality of first terminals electrodes, and the second terminal electrode films are respectively formed into a plurality of second terminal electrodes. A plurality of first plating layers are formed on the first terminal electrodes respectively, and a plurality of second plating layers are formed on the second terminal electrodes respectively, so as to form a plurality of multilayer ceramic capacitors.

According to an embodiment of the present disclosure, the above-mentioned preparing each of the first ceramic green sheet and the second ceramic green sheet includes: preparing a ceramic slurry; performing a foil casting step on the ceramic slurry to form a ceramic thin film; and Dry the ceramic film.

According to an embodiment of the present disclosure, forming the first internal electrode layer and the second internal electrode layer includes using a printing method.

According to an embodiment of the present disclosure, before performing the chamfering process, the above-mentioned method further includes performing a binder burn out process on the laminated structure to remove the first ceramic green sheet unit and the second ceramics of each laminated structure. Adhesive in the green unit.

According to an embodiment of the present disclosure, the above-mentioned forming of the first terminal electrode film and the second terminal electrode film includes using an adhesion method.

According to an embodiment of the present disclosure, both the first terminal electrode film and the second terminal electrode film described above include copper.

According to an embodiment of the present disclosure, the first coating layer and the second coating layer both include tin and nickel.

According to an embodiment of the present disclosure, after forming the first coating layer and the second coating layer, the above method further includes: performing a testing operation on the multilayer ceramic capacitors; and packaging the multilayer ceramic capacitors after the testing operation.

Please refer to FIG. 1 , which is a flowchart of a method for manufacturing a multilayer ceramic capacitor according to an embodiment of the present disclosure. When manufacturing the multilayer ceramic capacitor, step 100 may be performed first to prepare several first ceramic green sheets and several second ceramic green sheets. In some examples, a ceramic slurry is prepared first when preparing the first ceramic green sheet and the second ceramic green sheet. For example, the ceramic slurry can be prepared using a powder ball milling process. In the powder ball milling process, the materials of the ceramic slurry, including ceramic powders, solvents, adhesives, dispersants, plasticizers, etc., can be put into the ball mill to grind these materials by the ball mill and uniformize the materials. Mixed into a ceramic slurry.

After the preparation of the ceramic slurry is completed, a film forming step is performed on the ceramic slurry to form a ceramic film. In the film forming step, the ceramic slurry is sent to the container of the doctor blade machine, and the distance between the doctor blade and the carrier film is adjusted. With the advancement of the carrier film, the ceramic slurry is formed on the carrier film. Thin films of required thickness. After the ceramic film is formed, the ceramic film can be dried to form a first ceramic green sheet and a second ceramic green sheet.

Next, step 110 may be performed to form a plurality of first internal electrode layers on a surface of each of the first ceramic green sheets, and a plurality of first internal electrode layers on a surface of each of the second ceramic green sheets, using, for example, printing. a second inner electrode layer. For example, a suitable screen plate and internal electrode paste can be selected according to product specifications, and the internal electrode paste can be printed on the surface of the first ceramic green sheet and the surface of the second ceramic green sheet through a screen plate by a printer. In some examples, on each first ceramic green sheet, the first internal electrode layers are separated from each other, and on each second ceramic green sheet, the second internal electrode layers are separated from each other. The material of the first internal electrode layer and the second internal electrode layer may include copper, for example.

After the first internal electrode layer and the second internal electrode layer are completed, step 120 may be performed to firstly stack the first ceramic green sheets and the second ceramic green sheets in a staggered manner according to product requirements, and then press the first ceramic green sheets and the second ceramic green sheets. The stacking of ceramic green sheets forms a dense laminate. In some examples, the surface of the first ceramic green sheet with the first internal electrode layer faces upward, and the surface of the second ceramic green sheet with the second internal electrode layer faces upward, whereby the first internal electrode layer It is physically separated from the second inner electrode layer. In other words, a first ceramic green sheet or a second ceramic green sheet may be interposed between the adjacent first internal electrode layers and the second internal electrode layers. In addition, in the layered body, the first internal electrode layer and the second internal electrode layer correspond to each other up and down in a one-to-one manner.

Next, step 130 may be performed to perform a cutting process on the laminated body. In the cutting process, the laminated body can be cut according to the size requirements of the product, such as in the transverse direction and the longitudinal direction, so as to form several laminated structures. Please refer to FIG. 2 , which is a schematic cross-sectional view of a multilayer structure of a multilayer ceramic capacitor according to an embodiment of the present disclosure. The layered structure 300 includes a plurality of first ceramic green sheets 310 and a plurality of second ceramic green sheets 320 which are alternately stacked. Each first ceramic green sheet unit 310 includes a portion 312 of the first ceramic green sheet and a first internal electrode layer 314 . Each second ceramic green sheet unit 320 includes a portion 322 of the second ceramic green sheet and a second internal electrode layer 324 . The laminated structure 300 has a first end surface 302 and a second end surface 304 , wherein the first end surface 302 and the second end surface 304 are respectively located on opposite sides of the laminated structure 300 .

Please refer to FIG. 3 and FIG. 4 at the same time, wherein FIG. 3 is a schematic top view of a first ceramic green chip unit of a multilayer ceramic capacitor according to an embodiment of the present disclosure, and FIG. 4 is an embodiment of the present disclosure. A schematic top view of the second ceramic green chip unit of a multilayer ceramic capacitor of this method. In the first ceramic green sheet unit 310, the first internal electrode layer 314 covers the surface 312a of a portion 312 of the first ceramic green sheet, but does not cover the entire surface 312a, as shown in FIG. 3 . In the second ceramic green sheet unit 320, the second internal electrode layer 324 covers the surface 322a of a portion 322 of the second ceramic green sheet, but also does not cover the entire surface 322a, as shown in FIG. Furthermore, in the build-up structure 300 , all the first internal electrode layers 314 extend to the first end face 302 of the build-up structure 300 , and all the second internal electrode layers 324 extend to the second end face 304 of the build-up structure 300 . Moreover, the adjacent first internal electrode layers 314 are physically separated from the second internal electrode layers 324 .

After the cutting process is completed, step 140 may be selectively performed according to requirements to perform a firing process on the laminated structures 300 to remove the first ceramic green sheet unit 310 and the second ceramic green sheet unit 320 of each laminated structure 300 in the adhesive. In some examples, the build-up structure 300 may be placed in a baking apparatus to burn off the adhesive in the build-up structure 300 during the burn-out process.

Next, step 150 may be performed to perform a bevel process on the build-up structures 300 . In some examples, each corner of the layered structure 300 may be smoothed by rolling the layered structure 300 .

After the chamfering process is completed, step 160 may be performed to form a plurality of first end electrode films to cover the first end faces 302 of the laminated structures 300 respectively. Furthermore, a plurality of second end electrode films are formed to cover the second end surfaces 304 of the laminated structures 300 respectively. In some examples, the first end electrode film and the second end electrode film can be formed by adhering a material with good conductivity on the first end surface 302 and the second end surface 304 of the laminated structure 300 by means of an adhesion method. In some demonstrative examples, both the first terminal electrode film and the second terminal electrode film include copper.

After the first terminal electrode film and the second terminal electrode film are formed, step 170 may be performed to sinter the laminated structure 300 . The sintering process can make each laminated structure 300 form a laminated ceramic body, make the first terminal electrode films form a plurality of first terminal electrodes 330 respectively, and make the second terminal electrode films form a plurality of second terminal electrodes 340 respectively. After the sintering process, the first terminal electrode 330 and the second terminal electrode 340 can be more closely combined with the two ends of the laminated structure 300, thereby improving the electrical properties.

After the sintering process is completed, step 180 may be performed to form a plurality of first plating layers 350 on the first terminal electrodes 330 of the stacked structures 300 and a plurality of second plating layers 360 respectively on the stacked layers by using, for example, an electroplating technique A plurality of multilayer ceramic capacitors 370 are formed on the second terminal electrode 340 of the structure 300 , as shown in FIG. 5 . In some exemplary examples, the first plating layer 350 and the second plating layer 360 both include tin and nickel, wherein the nickel can protect the first terminal electrode 330 and the second terminal electrode 340, and the tin can help the multilayer ceramic capacitor 370 to adhere to, for example, on the circuit board. Since the layered structure 300 has been subjected to the bevel process, after the sintering process and the electroplating process, the stress on the corners of the first plating layer 350 and the second plating layer 360 can be reduced.

After the first plating layer 350 and the second plating layer 360 are formed, step 190 may be selectively performed to test the multilayer ceramic capacitor 370 according to requirements, for example, according to product requirements of customers. The MLCC 370 after the test can be classified according to the test results and the quality specifications required by the customer. Next, step 200 can be performed to package the tested multilayer ceramic capacitors 370 . For example, tape and reel packaging techniques can be used to package these MLCCs 370 to facilitate application.

It can be seen from the above-mentioned embodiments that one of the advantages of the present disclosure is that in the method for manufacturing a multilayer ceramic capacitor of the present disclosure, the multilayer structure is first cornered, and then the ceramic body and the metal terminal electrodes of the multilayer structure are densely formed at the same time during sintering. Compared with the conventional fabrication method of sintering the ceramic body first and then chamfering, the method of the present disclosure can avoid the mechanical stress of chamfering on the dense ceramic body and the stress generated by the temperature change of the sintered terminal electrodes.

Another advantage of the present disclosure is that because of the method for manufacturing a multilayer ceramic capacitor of the present disclosure, the ceramic body and the metal terminal electrodes are sintered together, so that the terminal electrode sintering process can be omitted, thus simplifying the process and shortening the process time. , which can increase productivity.

Although the present disclosure has been disclosed above with examples, it is not intended to limit the present disclosure. Anyone with ordinary knowledge in this technical field can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the appended patent application.

100: Steps 110: Steps 120: Steps 130: Steps 140: Steps 150: Steps 160: Steps 170: Steps 180: Steps 190: Steps 200: Steps 300: Laminated Structure 302: First end face 304: Second end face 310: The first ceramic green sheet unit 312: Parts 312a: Surface 314: first inner electrode layer 320: Second ceramic green sheet unit 322: Parts 322a: Surface 324: second inner electrode layer 330: First terminal electrode 340: The second terminal electrode 350: First Plating 360: Second Plating 370: MLCC

In order to make the above and other objects, features, advantages and embodiments of the present disclosure more clearly understood, the accompanying drawings are described as follows: 1 is a flowchart illustrating a method for manufacturing a multilayer ceramic capacitor according to an embodiment of the present disclosure. 2 is a schematic cross-sectional view illustrating a multilayer structure of a multilayer ceramic capacitor according to an embodiment of the present disclosure. 3 is a schematic top view illustrating a first ceramic green chip unit of a multilayer ceramic capacitor according to an embodiment of the present disclosure. 4 is a schematic top view illustrating a second ceramic green chip unit of a multilayer ceramic capacitor according to an embodiment of the present disclosure. 5 is a schematic cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present disclosure.

Domestic storage information (please note in the order of storage institution, date and number) none Foreign deposit information (please note in the order of deposit country, institution, date and number) none

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Claims (8)

A method for manufacturing a multilayer ceramic capacitor, comprising: preparing a plurality of first ceramic green sheets and a plurality of second ceramic green sheets; forming a plurality of first internal electrode layers on a surface of each of the first ceramic green sheets, and a plurality of second internal electrode layers on a surface of each of the second ceramic green sheets; staggered stacking and pressing the first ceramic green sheets and the second ceramic green sheets to form a laminate; A cutting process is performed on the laminated body to form a plurality of laminated structures, wherein each of the laminated structures includes a plurality of first ceramic green sheet units and a plurality of second ceramic green sheet units that are alternately stacked, and each of the first ceramic green sheet units A ceramic green sheet unit includes one of the first internal electrode layers, each of the second ceramic green sheet units includes one of the second internal electrode layers, wherein each of the laminated structures has opposite to each other A first end surface and a second end surface, the first internal electrode layers extend to the first end surface, the second internal electrode layers extend to the second end surface, and the adjacent first internal electrode layers and the The second inner electrode layer is physically separated; performing a chamfering process on each of the laminated structures; forming a plurality of first terminal electrode films to cover the first end surfaces of the laminated structures respectively, and a plurality of second terminal electrode films to cover the second end surfaces of the laminated structures respectively; After forming the first terminal electrode films and the second terminal electrode films, a sintering process is performed on the laminated structures, so that each laminated structure forms a laminated ceramic body, and the first terminal The electrode films respectively form a plurality of first end electrodes, and the second end electrode films respectively form a plurality of second end electrodes; and A plurality of first plating layers are formed on the first terminal electrodes respectively, and a plurality of second plating layers are respectively formed on the second terminal electrodes to form a plurality of multilayer ceramic capacitors. The method of claim 1, wherein preparing each of the first ceramic green sheets and the second ceramic green sheets comprises: prepare a ceramic slurry; performing a film forming step on the ceramic slurry to form a ceramic film; and A drying process is performed on the ceramic film. The method of claim 1, wherein forming the first internal electrode layers and the second internal electrode layers comprises using a printing method. The method of claim 1, wherein before performing the chamfering process, the method further comprises performing a burning process on the laminated structures to remove the first ceramic green sheet units of each of the laminated structures with the adhesive in the second ceramic green sheet units. The method of claim 1, wherein forming the first terminal electrode films and the second terminal electrode films comprises using an adhesion method. The method of claim 1, wherein both the first terminal electrode film and the second terminal electrode film comprise copper. The method of claim 1, wherein both the first coating layer and the second coating layer comprise tin and nickel. The method of claim 1, wherein after forming the first plating layers and the second plating layers, the method further comprises: performing a test operation on the multilayer ceramic capacitors; and After the test operation, the MLCCs are packaged.

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