JPH0391217A - Laminated ceramic capacitor and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a laminated ceramic capacitor of high laminated layer having no positional deviation of inner electrodes and no short circuit by passing individual inner electrodes alternately laminated with dielectric layers to both ends for leading outer electrodes, alternately insulating the inner electrodes at every other one at both ends, and providing the outer electrodes. CONSTITUTION:Dielectric ceramic green sheets 11a on which inner electrodes 12 are printed are sequentially laminated repeatedly at the same position while applying a temporary pressure to manufacture a laminated molded form. The obtained molded form is cut into chips, the end face of the side coated with the outer electrodes of the chip is masked, a barium titanate film is formed as an insulating film 14, and insulated. Inner electrodes 12 not insulated previously at the other end face are entirely similarly insulated, chips in which the electrodes 12 of both ends are alternately insulated at every other layer are baked, coated with silver paste as outer electrodes, and baked to form outer electrodes 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multilayer ceramic capacitor and a method for manufacturing the same.

BACKGROUND OF THE INVENTION In recent years, as electronic devices have become smaller, the demand for multilayer ceramic capacitors has increased.

A general method for manufacturing a multilayer ceramic capacitor is to first prepare a green sheet using a doctor blade method or the like using a nullary made of dielectric powder such as barium titanate ceramic, an organic binder, and an organic solvent.

Next, internal electrodes are formed on this sheet by screen printing or the like using an electrode paste whose main component is a noble metal such as palladium or platinum.

Next, apply a pressure of 9/cd to 5 to 10 while shifting the position of each layer so that the internal electrode layers sandwich the dielectric layers and alternately face each other. After laminating multiple sheets and obtaining the desired number of layers, 20~
Pressure is applied at a pressure of so kg/ci, and after cutting into chips of a desired size, they are fired at 120σC to 1400°C. Silver, silver-palladium, or the like is coated on the internal electrodes appearing at both ends of the sintered body thus obtained, and the external electrodes are formed by baking to manufacture a multilayer ceramic capacitor.

Further, FIG. 6 shows the appearance and interior of a conventional multilayer ceramic capacitor, in which 1 is a dielectric layer, 2 is an internal electrode, and 3 is an external electrode.

Problems to be Solved by the Invention However, in the structure described above, as the number of laminated layers increases, errors in positioning when the internal electrodes are alternately opposed become a problem, and misalignment of the internal electrode layer portions becomes noticeable. This is a major problem in the manufacture of multilayer ceramic capacitors, as it causes variations in capacitance in the fired elements.

Furthermore, another problem is that due to displacement and pressure during lamination, in the case of a highly laminated laminate, as shown in FIG. The internal electrodes 2 are bent at the ends of the bent portions 2 and 2, and the opposing internal electrodes 2
There were many cases where short-circuiting occurred and caused defects.

In view of the above-mentioned problems, the present invention provides a highly laminated multilayer ceramic capacitor that is free from misalignment of internal electrodes and short circuits due to lamination, and a method for manufacturing the same.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a structure in which the individual internal electrodes alternately laminated with dielectric layers penetrate to both ends from which the external electrodes are taken out, and buttons are attached to both ends. The internal electrodes are alternately insulated every other layer, and external electrodes are provided at both ends.

Effects of the present invention With the above-described configuration, the step of shifting the position of the green sheet in the conventional manufacturing method 51 is omitted, so there is no problem with misalignment of the internal electrodes, and the entire surface of the internal electrodes can be used effectively. Since it becomes an electrode, a short circuit at the end of the effective electrode portion shown in FIG. 6 is prevented, and at the same time, a larger i-electric capacity can be obtained with the conventional number of laminated layers of 9 by greatly increasing the area of the effective electrode portion. is possible.

Furthermore, when a continuous rod-shaped internal electrode pattern with a variable width is used in the above-described configuration, it is possible to cut the laminated molded product at an arbitrary length to create a laminated molded product with various capacitances from the same lot of laminated molded products. Ceramic capacitors can be obtained. The capacitance can be arbitrarily controlled by changing the cutting position of the tab 9.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows that each internal electrode 12 in an embodiment of the present invention penetrates to both ends from which external electrodes 13 (to be described later) are taken out, and the internal electrodes 12 are connected alternately every other layer at both ends. This figure shows a cross section of a multilayer ceramic capacitor having a structure in which an external electrode 3 is provided after insulation treatment is performed using an edge film 14. In FIG. 1, 11 is a dielectric layer.

Next, the manufacturing method will be described in detail. 1. First, prepare a dielectric ceramic green sheet with a thickness of 20 μm mainly composed of barium titanate and an internal electrode paste (ML3724 manufactured by Shoei Kagaku Kogyo Meiko Co., Ltd.) mainly composed of palladium. Using a screen printing plate with a diameter of 100111ff and a distance between adjacent electrodes of 5 mm,
While applying a temporary pressure 10 of 9/d using a conventional method, dielectric ceramic green sheets 11a having internal electrodes 12 printed thereon are repeatedly laminated in the same position as shown in FIG. 2, thereby forming a 60-layer laminate molded product. was produced, and finally, pressing was performed under the conditions of 20 kg/c for 11.3 seconds as main pressurization. Next, the obtained laminated molded body is cut into chips of a desired size, and the end face of the obtained chip on the side where the external electrode is applied is masked as shown in Fig. 3, and titanium is coated. A barium titanate film with a thickness of 1000 to 3000 A is formed as an insulating film on the internal electrode 12 every other layer by RF sputtering using barium acid as a target, and an insulating treatment is performed. Next, the other remaining end surface of the internal electrode 12, which had not been subjected to the insulation treatment in the above, was subjected to the insulation treatment using the method completely similar to that described above. In FIG. 3, reference numeral 15 indicates a mask plate, and reference numeral 16 indicates a chip outer periphery.

In this way, the internal electrodes 12 at both ends were insulated every other layer as shown in FIG.
After holding for an hour and removing the binder, it was heated to 1300°C for 2
Time firing was performed. After firing, the obtained sintered body was packed into 5g of elements.
Pour 400 y/m of pure water into a pot with No. 80 sandpaper pasted on the inner wall, and after chamfering with a ball mill, apply commercially available silver paste (GM-104, manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd.) to the external electrode. Apply as 80
Baking was performed at 0'C for 30 minutes, and the capacitance as a multilayer ceramic capacitor was measured.

The table below shows the hit rate and failure status due to short circuit when the capacitance of the obtained multilayer ceramic capacitors is compared with the design value in manufacturing using the conventional method and the method according to the present invention, and the number of samples is 1,000. It can be seen that the present invention clearly improves the accuracy of capacitance and the yield due to short circuits.

Figure 4 shows the difference in the number of laminated layers required to obtain a certain capacitance between the conventional method and the method according to the present invention, and it is clear that the product according to the present invention is a structurally effective electrode. It can be seen that since the area is larger than that of conventional products, it is advantageous in that a large electrical capacity can be obtained with a small number of laminated layers.

As described above, according to this embodiment, the individual internal electrodes of the multilayer ceramic capacitor penetrate to both ends from which the external electrodes are taken out, and the internal electrodes are alternately insulated every other layer at both ends. By providing an external electrode on top of the processed material, it is possible to eliminate misalignment of the internal electrode, improve the accuracy of capacitance, and further improve defects caused by short circuits in the internal electrode. . Furthermore, the product of the present invention has been proven to be an effective means for significantly increasing the capacitance of a multilayer ceramic capacitor from a structural standpoint.

In this example, sputtering was used to insulate the internal electrodes, but it was confirmed that the same effect could be obtained by vacuum evaporation.

Effects of the Invention As described above, the present invention provides a structure in which each internal electrode of a multilayer ceramic capacitor penetrates to both ends from which the external electrode is taken out.
By providing an external electrode on top of the internal electrodes, which are insulated alternately at every other layer at both ends, the problem of misalignment of the internal electrodes can be solved and the accuracy of the capacitance can be improved. improve the rate,
At the same time, it is an effective means for improving defects caused by short circuits in internal electrodes and increasing the capacitance of multilayer ceramic capacitors from a structural standpoint, and will bring revolutionary effects to the manufacturing of multilayer ceramic capacitors in the future. be.

[Brief explanation of drawings]

FIG. 1 shows that the individual internal electrodes of the embodiment of the present invention penetrate to both ends from which the external electrodes are taken out, and that the internal electrodes are insulated alternately at every other layer at both ends. FIG. 2 is a diagram for explaining the state of lamination in the present invention, and FIG. 3 is an explanatory diagram showing a cross section of a multilayer ceramic capacitor in which an external electrode is provided at the end of the capacitor. FIG. 4 is a diagram for explaining the state of masking during processing, and FIG. 4 is a diagram for explaining the difference in the number of laminated layers required to obtain a constant capacitance between the conventional method and the method according to the present invention. Fig. 6 is a partially cutaway view showing the structure of a conventional multilayer ceramic capacitor, and Fig. 6 is a view illustrating the bending of the internal electrode at the end of the effective electrode portion. ...Dielectric layer, 11a... Dielectric layer □ Green sheet, 12... Internal electrode, 13... External electrode, 14... Insulating film.

Claims (2)

[Claims] (1) The individual internal electrodes alternately laminated with dielectric layers penetrate to both ends from which external electrodes are taken out, and at both ends, the internal electrodes are alternately insulated every other layer, and A multilayer ceramic capacitor characterized by having external electrodes at both ends. (2) Internal electrodes are formed in a continuous rod-like pattern on dielectric ceramic green sheets, and the sheets are laminated at the same position without shifting the positions alternately, and the resulting laminated molded product is shaped into the desired size. After cutting into chips, one of the internal electrodes that appears at both ends is insulated by sputtering etc. every other layer.
The other internal electrode is a laminated layer characterized in that the internal electrodes that were not insulated in the above are insulated by sputtering or the like every other layer in order to avoid short circuits, and then fired, and then external electrodes are provided at both ends. Method of manufacturing ceramic capacitors.