JPS58212121A - Method of producing laminated ceramic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention concerns a lamination method in the manufacturing process of a multilayer ceramic capacitor.

The conventional method for laminating multilayer ceramic capacitors is the green sheet method, for example, by creating a green ceramic film using a doctor blade method, printing an electrode paste that will become internal electrodes on the green ceramic film, and then stacking multiple layers to form counter electrodes. The sheets are laminated, and at the same time, a green ceramic film (without internal electrode paste printed thereon), which serves as an insulator, is placed on both sides and laminated. In the case of the screen printing method, the structure is the same, except that the ceramic film is formed by screen printing. In any case, when laminating layers in this way, if there are components that easily evaporate among the raw materials of the ceramic composition, these components will evaporate from the surface during the firing process, and the composition of the ceramic composition near the surface of the multilayer ceramic capacitor chip will change. The ratio is different from that inside the chip, which not only reduces the capacitance and insulation resistance of the ceramic layer sandwiched between the internal electrodes located close to the chip surface (but also makes it easy for dielectric breakdown to occur in these ceramic layers). This had the disadvantage of resulting in a monolithic ceramic capacitor with low reliability.

The purpose of the present invention is to eliminate such conventional drawbacks, suppress the decrease in the capacitance and insulation resistance of the ceramic layer, and achieve the same level of characteristics as the inside of the chip in the internal electrode located close to the surface of the multilayer ceramic capacitor chip. The present invention provides a method for manufacturing a highly reliable multilayer ceramic capacitor in which the characteristics between each ceramic layer are uniform. The present invention provides a method for manufacturing a multilayer ceramic capacitor, in which a green ceramic film that is sandwiched between internal electrodes and laminated in the lamination process contains more components that easily evaporate among the raw materials of the ceramic composition. The green ceramic film is placed closer to the chip surface than the inner electrodes located on both outer sides of all the plurality of internal electrodes in the multilayer ceramic capacitor chip, and is laminated and crimped. There is.

In other words, the present invention adds a ceramic composition film containing a larger amount of raw material components that easily evaporate during the firing process to both outer sides of a plurality of internal electrodes, thereby reducing uneven evaporation of the ceramic composition in each part of the chip during firing. After the raw material components of the ceramic composition that are less likely to evaporate evaporate near the chip surface (where evaporation occurs more actively than inside the chip), the composition ratio of the ceramic composition between the near surface and inside of the chip after firing is changed. Care has been taken to ensure that it is almost uniform.

A detailed explanation will be given below according to examples. FIG. 1 is a schematic cross-sectional view showing a multilayer ceramic capacitor manufactured by the method of the present invention. pb(Fe 1/2 ・N
b 1/l) 0.6? (Fs 2/s -wl/
a) A composite perovskite dielectric material shown by 0.3303 was pre-fired and ground in a ball mill, and then 30 μm Green Ceramic 4-sheet 2 was prepared using the doctor grade method.
was created. An internal electrode (TEPACE) (Ag-Pd type) is printed on the green ceramic sheet by a screen printing method to form an electrode layer 3.3'. In this example, 61 sheets of these are laminated, and ceramic sheets 1) having no electrode layer printed on top and bottom thereof are laminated as protective films. (10 sheets in this example) The ceramic sheet 1 contains 1.0% PbO, which is a naramic composition that easily evaporates during the firing process.
The membrane has a ceramic composition containing 0% by weight. Next, after thermocompression bonding with a hot press machine and cutting into a predetermined shape, binder removal, firing, and external electrode formation were performed. The capacitance and insulation resistance of the obtained multilayer ceramic capacitor chip were determined, and the capacitance and insulation resistance of each ceramic layer sandwiched between internal electrodes were also measured. The results are shown in the table and FIG.

For table comparison, raw chips with a conventional laminated structure in which 10 non-printed green ceramic films of the same composition as the green ceramic films inside the chip were laminated above and below the internal electrode layer were also fired at the same time to obtain similar capacitance and insulation. Resistance was measured. Figure 2 shows the upper 2122 layers sandwiched between internal electrodes in a multilayer ceramic capacitor chip, numbered from the position closest to the chip surface, and the capacitance and insulation resistance at each location measured.
FIG. 3 is a diagram showing the relationship between each ceramic layer and the capacitance-resistance product at that location.

As is clear from the table and FIG. 2, in the manufacturing method according to the present invention, compared to the conventional method, the product of capacitance and insulation resistance of the ceramic layer sandwiched between internal electrodes does not decrease at all even in areas close to the surface, and throughout the entire layer. It shows a flat value and the conventional product has a high overall value, and the product of the capacitance and insulation resistance of the entire chip also shows a value that is higher than that of the conventional product. Further, in the embodiment, a case where PbO is included by 1.0 weight is shown, but depending on various conditions, the amount of PbO may be increased to about 5 weight.

As stated above (according to the present invention, it is possible to dramatically improve the characteristics of a multilayer ceramic capacitor, and it has become possible to provide a method for manufacturing a highly reliable multilayer ceramic capacitor).

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the laminated structure of the present invention. Figure 2 shows the relationship between the position of each ceramic layer sandwiched between internal electrodes and the capacitance-resistance product in a multilayer ceramic capacitor chip of the present invention and a conventional product. Tae. In the figure, 1 is a ceramic film that contains a larger amount of components that easily evaporate during the firing process among the raw material components of the ceramic composition, 2 is a ceramic film of a predetermined ceramic composition, and 3. It is an internal electrode. ~ , ~ (MΩ・) capacity
Insulation resistance 'iF

Claims (1)

[Claims] In a manufacturing method for multilayer ceramic capacitors, in which green ceramic films and internal electrodes are alternately laminated, and then pressure bonded, fired, and external electrodes are formed, the green ceramic film used in the lamination is laminated with the internal electrodes. There are two types of green ceramic films: one is located at a position closer to the capacitor surface than the internal electrode located on both sides of multiple internal electrodes, and the other is located closer to the capacitor surface than the internal electrode located on both sides. A method for manufacturing a multilayer ceramic capacitor, characterized in that a green ceramic film is used that contains a larger amount of components that easily evaporate during firing among the raw material components of a ceramic composition.