JPS61102717A - Manufacture of laminated ceramic capacitor - 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 (Field of Industrial Application) The present invention relates to an improvement in a method for manufacturing a multilayer ceramic capacitor used as an electronic component.

(Prior Art) Conventionally, multilayer ceramic capacitors are manufactured by printing an internal electrode paste containing a powdered conductive material on a raw ceramic sheet containing a dielectric material, drying it, and then aligning it in a circular pattern.
A plurality of sheets obtained by punching are laminated, thermocompression bonded to form a laminate, which is cut into a predetermined shape, depined, and fired.

It is manufactured through a process called external electrode attachment.

(Problems to be Solved by the Present Invention) As shown in FIG. 3, the crimping surfaces 4 of the upper die (upper punch) 3 and the lower die (lower punch) 2 of the thermocompression mold in the conventional manufacturing method of ceramic capacitors , 4' are flat surfaces, and the compressive force tends to be weak at the center of the mold and strong at the periphery. For this reason, the ceramic laminate 5 is formed by thermocompression bonding using this conventional mold.

The laminate was formed into a medium-height structure with a thick central portion (low density) and a thin peripheral portion (high density), and the density of the laminate also varied. Therefore, when chips of a predetermined shape are cut and fired from a ceramic laminate formed by this conventional method, the influence of variations in the density distribution of the ceramic laminate before firing remains.

As shown in FIG. 2, the sintering density of the chips cut out from the peripheral part of the thermocompression-bonded laminate was high, and the sintering density of the chips cut from the central part was low.

Such non-uniform density during firing increases the variation in the characteristics of the capacitor as a product, and is also a cause of so-called delamination 1, where the periphery of the f-res body (thermo-compression bonded laminate) peels off when it dries. Become.

This resulted in a decrease in the reliability of the capacitor.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems, and consists of laminating a plurality of dielectric ceramic sheets on which internal electrodes are printed, and applying pressure and temperature to The ceramic compression surfaces 4, 4' of the upper mold (upper punch) 3 and lower mold (lower punch) 2 of the thermocompression mold for molding a ceramic laminate by thermocompression bonding are arranged such that the center part is high and the periphery of the 2 It has a convex curved surface with a low part, making it possible to obtain a thermocompression-bonded ceramic laminate with uniform density.

(Example) An embodiment of the present invention will be described below.

As a ceramic material, pb ((Nb 'A' Fe
'7! )067(W'/3 ・F e 2/3
). 55) Using a robskite dielectric material as a composite with a 03'x composition, this was mixed, preheated, and dispersed in wet-milled powder and PVB, BPBG'i ethyl cellosolve to form a slurry, and the mixture was made into a slurry using a doctor blade method.
The entire µm Green Note (ceramic notebook) was molded. This Gree-7 Note: Punched out to a size of 130 x 160, and had 35 pieces on the Gree-7/- Note. An electrode film is formed by screen printing a single stroke. As shown in Figure 1, these 60 electrode films are fixed in a lower mold (lower groove/ch) in a mold frame 1.
2 and the upper mold (upper/cm) 3 that advances and retreats into the mold frame l toward the lower mold 2, the crimping surface 4.4'i from the center of the mold Laminated in a mold with a convex curved surface (d = 40 μm) that becomes lower toward the periphery,
After heating to 110° C., thermocompression bonding was performed at a pressure of 1 ton/crn2 to form a ceramic laminate 5.

The thus obtained laminate 5 is processed by a known method.
It was cut according to the ξ turf shape and V8 formation was performed.

Figure 2 shows the results of measuring the variations in firing density and chip thickness of the laminate formed in this way, and the results of measuring the variation in firing density and chip thickness of the laminate formed in this way, and the results obtained by placing the laminate at Z-1 in the ceramic laminate where the laminate chip before firing was bonded by thermocompression. This is a comparison. As is clear from Figure 2, the thickness of the ceramic before firing (thermocompression bonded) and the thickness of the laminated ceramic after firing change approximately in proportion, and the thickness of the ceramic laminated ceramic before firing (before firing) If the variation in the laminated body is small, the variation in the thickness of the laminated chip after firing is also small, and it is possible to obtain a laminated chip, f, with a uniform firing density.

Furthermore, lamination failure occurs after the organic binder decomposes when the laminated body density becomes high.

This is often caused by insufficient degassing, but according to the method of the present invention, it is possible to achieve an approximately uniform compressed density over the entire surface of a thermocompressed ceramic laminate, thereby eliminating delamination defects. The outbreak was also suppressed. 2. In the present invention, the laminated ceramic is not limited to a tsukku capacitor, but also a laminated structure bonded by thermocompression. Needless to say, it is also effective in manufacturing other parts that have the same properties.

(Effects of the Invention) According to the present invention, since the compressed density of the thermocompressed laminated ceramic can be made uniform, it is possible to reduce the variation in the firing density of the laminated ceramic after firing (sintering), and it is also possible to Since the occurrence of /yon can also be reduced, highly reliable multilayer ceramic capacitors can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the thermocompression mold of the present invention, Fig. 2 is a diagram showing the relationship between the chip cutting position of the laminated ceramic and the chip thickness during and after firing, and Fig. 3 is a schematic diagram of the conventional thermocompression mold. It is a diagram. 2: Lower mold of thermocompression mold, 3: Upper mold of thermocompression mold, 4
．． 4': crimping surface. , ==two==end・- Figure 3Figure 2

Claims (1)

[Claims] 1. A method for manufacturing a ceramic capacitor in which a plurality of parallel internal electrodes facing each other in a layered manner are provided inside a dielectric ceramic, and terminal electrodes are provided in the internal electrode lead-out portion. The ceramic pressing surfaces 4, 4' of the upper die 3 and the lower die 2 of a thermocompression mold for forming a ceramic laminate by laminating a plurality of ceramic sheets and thermocompression bonding at a predetermined pressure and temperature are A method for manufacturing a multilayer ceramic capacitor characterized by having a convex curved surface that is high and has a low peripheral portion.