JPS62115817A - Manufacture of laminated capacitor element - 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 a method of manufacturing a multilayer capacitor element, in particular a ceramic mainly composed of a composite perovskite solid solution containing lead is used as a dielectric material, and copper or copper is used as the internal electrode. The present invention relates to a method for manufacturing a multilayer capacitor element using an alloy containing as a main component.

BACKGROUND OF THE INVENTION In recent years, multilayer ceramic capacitors have been rapidly becoming popular due to the demand for smaller ceramic capacitor elements and larger capacitance. Multilayer ceramic capacitors are typically manufactured by a process of integrally firing internal electrodes and ceramics.

Barium titanate-based materials have traditionally been used as high-permittivity ceramic capacitor materials, but because the firing temperature is as high as 1,300°C, P is used as the internal electrode material.
It was necessary to use expensive metals such as tungsten and Pd.

In response, a multilayer capacitor element has been proposed that uses a barium titanate-based material that can be fired in a low oxygen partial pressure atmosphere and uses a base metal material such as Ni as the internal electrode.The manufacturing conditions are described in Japanese, Journal, of Applied, Physics, Subliment, 2O-4 (
1981) as reported in P147-150.

On the other hand, the inventors have already proposed a lead composite perovskite material that can be fired in a low oxygen partial pressure atmosphere and has high resistivity.

Problems to be Solved by the Invention Using an alloy mainly composed of copper and steel as the internal electrode,
During the manufacturing process of multilayer capacitor elements using ceramics mainly composed of a composite perovskite solid solution containing lead as a dielectric, the copper electrodes are oxidized during the firing process of the element, resulting in a decrease in the capacitance of the element or oxidation. There were problems such as the steel components reacting with the dielectric ceramic, reducing the insulation resistance of the element, and the dielectric ceramic being reduced, reducing the insulation resistance of the element and increasing dielectric loss. . The present invention provides a method for manufacturing a multilayer capacitor element that prevents oxidation of copper electrodes and reduction of dielectric material.

Means for solving problems Pb(Mg1,3Nb2t3)03 is the main component, Ca
, Sr, and Ba, and a ceramic having a composition containing an oxide of at least one component selected from the group consisting of , Sr, and Ba is used as the dielectric, and copper or an alloy containing copper as the main component is used as the internal TL pole, and the firing temperature of the element is set to T. ℃, when the atmospheric oxygen partial pressure during firing is Po2 atm, 800≦T≦1100. -2.
33+(2TV300)≦-loginPo2≦26-
(T/100).

According to the manufacturing method of the present invention, there are problems such as the copper electrode being oxidized and the capacitance of the device being reduced, and the oxidized steel component reacting with the dielectric ceramic to reduce the insulation resistance value of the device. A multilayer capacitor element with high insulation resistance (and no reduction in element capacitance) can be obtained without causing problems such as a decrease in the insulation resistance value of the element or an increase in dielectric loss due to the reduction of the body ceramic.

Example A material represented by the following compositional formula was used as the dielectric.

A: (Pb +, oo Ca 0.025) (Mg
xz+ Nb2. s)0. T.

Tio2s (Nitz2W 1/2) Q, 0503
．． 025B: (Pb 0.9 [I Sr 0.07
)(Mg1zs Nb2z3)o,as'['io
, +s 03.03 C2 (Pb l-00Ba O-05) 0-05
) (Nb2z3 )0-40Ti0.30 (Zl
ll/2 Wl/2 ) 0.30 03.05 The dielectric powder was manufactured according to a conventional ceramic manufacturing method. The calcination conditions were 800°C for 2 hours.

The pulverized calcined powder was mixed with an acrylic resin and a solvent and formed into a sheet with a thickness of 42 μm using a doctor blade. An electrode paste made of a mixture of metallic copper powder and acrylic resin solvent was printed on a sheet, laminated so that the electrodes were drawn out alternately, and then cut. The laminate is placed on top of coarse-grained zirconia laid inside a porcelain boat.

The binder was burnt out at 350° C. by flowing 1% 02-N2 gas.

FIG. 2 shows a cross section of a magnesia porcelain container into which a laminate is placed during firing, and FIG. 3 shows a cross section of a firing furnace core tube. In the magnesia porcelain container 21, the above-mentioned calcined powder 22 was spread about 1/3 of the volume, and 200 mesh ZrO2 powder 23 was placed in a ladle.
mm, and the burnout laminate 25 was placed thereon. Cover the magnesia porcelain lid 24, insert it into the core tube 26 of the tubular electric furnace, deaerate the inside of the core tube with a rotary pump, replace it with N2-82 mixed gas, and add N2 and N2 gas to a predetermined oxygen partial pressure. A mixed gas was flowed while adjusting the mixing ratio of , and the temperature was raised to a predetermined temperature at a rate of 400°C/hr for 1 hour, held for 2 hours, and then lowered at a rate of 400'C/hr.

Po2 in the reactor core tube was determined from the following equation based on the voltage E (V) between the electrodes drawn from the platinum electrodes configured on the atmospheric side of the inserted stabilized zirconia oxygen sensor 27 and on the inner side of the reactor.

Po 2 =0.2・exp(4FE/RT)
Here, F is the Faraday constant of 96489 coulombs, R is the gas constant of 8.3144 J/deg-mol, and T is the absolute temperature.

In the fired multilayer capacitor element, copper electrodes (containing an inorganic binder) were formed as external electrodes by a printing method, and baked at 700°C Po2 = 1xlO-6 in the same manner as the above-mentioned baking method.

What is the external shape of a multilayer capacitor element? , Ox5. Ox1. Om
m, the effective electrode area is 18 mm2 (5,Ox3
．． 6nvn), the thickness of the electrode layer was 2.0 μm, the dielectric layer was 30 μm per layer, there were 30 effective layers, and one ineffective layer on the top and bottom.

The multilayer capacitor element has a capacitance, janδ, of 1kllz,
Measurements were made under an electric field of IV/mm. Also, the resistivity is 1k
The voltage of V/mn+ was determined from the value 1 minute after application.

Table 1 shows the composition of the dielectric used, the electrode composition, the oxygen partial pressure during firing, the firing temperature, the dielectric constant, tan δ, and resistivity.

FIG. 1 shows the oxygen partial pressure on the vertical axis and the firing temperature on the horizontal axis, and the shaded area is the inversion of the invention.

The conditions used in the present invention are limited for the following reasons. First, regarding the upper limit of oxygen partial pressure during firing, as shown in Table 1 and sample number 11.1.6 in Figure 1,
Each firing temperature and firing atmosphere oxygen partial pressure is 1 at 830℃.
At ×10−3 atm, 1 = 10−3 atm at 9600C, and 1×10−4 atm at 1030°C, the resistance value of the element becomes 1×10·9Ω or less, as shown in sample number 12.2.7. 1 x 10-4 atm at 860℃, 98
1 x 10-6 atm at 0℃, 1.10-6 at 1030℃
At atmospheric pressure, the resistance value of the element is I×10◆9Ω or more, so in Figure 1, the resistance value of -1ogP passing between these two groups is
The boundary was o2-2.33+(2T/300). Regarding the lower limit, as shown in sample number 15.5.10, 1 x l at 900℃, I at 1050℃
X 1.l at 10-17 atm and 1100°C Q-16
At atmospheric pressure, the resistance value of the element is still less than 1 × 10-9Ω, and as shown in sample number 14.4.9, at 900°
l x l at C - Q-18 atm, l < at 1050°C
l Q-Is atm, I x 10-14 at 1080°C
At atmospheric pressure, the resistance value of the element is 1×10・9Ω or more, so in Figure 1, the resistance value of -1ogP passing between these two groups is
o2-26-(T/100) became the boundary.

Furthermore, if the firing temperature is above 1100°C, as shown in sample number 16, the copper melts during firing and the electrodes are not formed in a layered manner but are unevenly distributed in islands, resulting in a decrease in capacity, and below 800°C, as shown in sample number 17. However, since the dielectric material does not become denser and the capacitance decreases, it is excluded from the scope of the invention.

Effects of the Invention According to the method for manufacturing a multilayer capacitor element within the scope of the present invention,
Pb(Mg+z+Nb2z3)0 with high dielectric constant
A multilayer capacitor element having a small size, large capacity, low cost, and high reliability can be obtained by using a material containing 3 as a main component as a dielectric and using copper and an electrode material containing copper as a main component.

[Brief explanation of drawings]

FIG. 1 is a graph showing the range of firing temperature and oxygen partial pressure atmosphere during firing in the manufacturing method of a multilayer capacitor element according to the present invention, FIG. 2 is a cross-sectional view of the magnesia container during firing, and FIG.
The figure is a cross-sectional view of the firing furnace core tube. 21. Magnesia porcelain container, 22: Calcined powder, 23: Coarse grain zirconia, 24: Magnesia container lid, 25: Laminate sample, 26: Furnace tube, 27: Stabilized zirconia oxygen sensor. Name of agent: Patent attorney Toshio Nakao and one other person (Figure 1) ('C)

Claims (1)

[Claims] A ceramic having a composition mainly composed of Pb(Mg_1_/_3Nb_2_/_3)O_3 and containing an oxide of at least one component of the group consisting of Ca, Br, and Ba is used as a dielectric, and the internal electrode When copper or an alloy containing copper as the main component is used, the firing temperature of the element is T°C, and the atmospheric oxygen partial pressure during firing is Po_2 atmospheres, 800≦T≦1100 −2.33+(2T/300)≦ -log_mPo_2
A method for manufacturing a multilayer capacitor element, characterized in that firing is performed under conditions in a range of ≦26-(T/100).