JPS63187612A - Method of forming laminated layers of laminated unit - 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 is an electronic component widely used in the electronics field, such as a multilayer ceramic capacitor, a multilayer piezoelectric element, etc., in which ceramic dielectrics and internal electrodes are layered. The present invention relates to a method for laminating a laminated body.

[Conventional technology]

In the past, many inventions have been proposed as methods for manufacturing multilayer ceramic capacitors, which are an example of bipedal laminates, but they can be categorized into: (1) green sheet method; 2) There is a printing method;
The internal electrode molding methods include (3) paste method, (4)
There are injection methods, each of which has been put into practical use.

Among the above molding methods, the so-called green sheet method, which is a combination of (1) and (3), mixes ceramic powder and an organic binder to create a slurry, which is then cast using a doctor blade or the like. A paste made of a mixture of metal powder, an organic solvent, and a binder is printed on a formed green sheet, and the sheets are laminated and pressed together.

In the so-called printing method, a dielectric paste containing ceramic powder, a solvent, and a binder and an internal electrode paste containing metal powder are alternately printed.

[Problem that the invention seeks to solve]

Multilayer ceramic capacitors manufactured using conventional manufacturing methods have been one of the driving forces behind the rapid development of the electronics field and have been extremely useful.

However, these methods have advantages and disadvantages, and are not necessarily satisfactory manufacturing methods. Among these, an important problem to be solved is a method of forming internal electrodes that is inexpensive and highly conductive. To explain the problems of this internal electrode in detail, (1) conductivity,
(2) Using platinum, palladium, or expensive materials with a high content of these in terms of melting point and reactivity; (2) electrode breakage, variations in electrostatic customer traffic, delamination, and cracks due to printing thickness; ( 3) When using cheap metals such as iron and nirakera, it is necessary to use expensive gases such as reducing, inert, and neutral gases to prevent oxidation of the metal powder.

[Means and effects for solving the problems] The present invention was conceived in view of the above-mentioned problems, and it is possible to use iron, nickel, and inexpensive metal foil as the internal electrode material, and to have uniform thickness and An object of the present invention is to provide a method for laminated molding of a laminate consisting of a dielectric material and internal electrodes, which can obtain internal electrodes with excellent conductivity, have excellent performance, and reduce the overall cost. In this method, a sheet of metal foil is placed on a dielectric material, the dielectric material is masked in the necessary parts of the metal foil, the unnecessary parts of the metal foil are etched, and the etched parts are etched. A dielectric material is laminated on the entire surface including the substrate, and each step is sequentially repeated as many times as necessary.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a multilayer ceramic capacitor formed by the method of the present invention. This structure is the same as that of conventional capacitors formed by other multilayer forming methods. In the figure, 1 indicates a ceramic dielectric, 2 is an internal electrode, and 3 is an external electrode. The external electrodes 3 are fixed to both outer sides of the ceramic dielectric,
A plurality of stacked internal electrodes 2 are alternately connected to the bipolar electrodes 3, 3. A conducting wire (not shown) is then connected to the bisexual part electrode 32.3 by soldering.

The method of laminating the multilayer ceramic capacitor according to the present invention will be explained below with reference to FIGS. 2 to 5.

First, a sheet metal foil 5 such as Nirakera foil is pasted on the green sheet 4 prepared in advance with adhesive, and then a sheet of metal foil 5 of the same size as the internal electrode 2 of the product shown in Fig. 1 is attached to the surface of the metal foil 5. The ceramic dielectric 6 is masked by a printing method using ceramic paste (FIG. 2). FIG. 5 is a plan view showing the ceramic dielectric 6 in a masked state.

After drying, the unmasked portion of the metal foil 5 is immersed in an etching solution such as an acid or alkaline solution to dissolve it, and then dried to obtain a predetermined internal electrode size (FIG. 3).

Next, on the entire surface including the green sheet 4, a ceramic dielectric 7 is laminated by the above-described printing method on the top surface of the metal oil 5 to a predetermined thickness and so that the top surface is flat, and is dried to form an internal layer inside the dielectric. A first layer encapsulating the electrode is obtained.

The above steps are repeated several times on the top surface of the first layer to sequentially laminate the ceramic dielectric and the metal foil that will become the internal electrodes.
A green sheet 4 is laminated on the top layer, and then the whole is pressurized and heated to form a bond (FIG. 4).

In this process, the metal foils to be laminated are alternately shifted to one side, each odd-numbered layer and every even-numbered layer, and after the above-mentioned pressure forming, the metal foils are alternately exposed at positions as shown by the chain lines in Figure 4. disconnect.

After that, the binder is removed and sintering is performed in the atmosphere.
After cooling, the external electrodes are baked by a conventional method to obtain the chip-type multilayer ceramic capacitor shown in FIG.

According to the method of the present invention, since metal foil is used for the internal electrode 2, deterioration of the conductivity of the internal electrode 2 can be prevented even when heated in the atmosphere with high oxygen partial pressure during the binder removal and sintering steps. In addition, inexpensive iron, nickel, etc. can be used for the internal electrodes 2, and manufacturing costs can be reduced.

The steps of the above embodiment will be explained in more detail.

Green sheet 4 has main components BaO, TiO2 and Cab.
, SnO2, B12O3, and PbO are used, and its size is 50 mm x 50 mm x Q, 2 m.
m, and one side or 1. +- Paste a 50 mm x 50 mm x 3 μm nickel foil coated with iso adhesive and insert into a screen printing machine.

Here, with a 300 mesonyu stainless steel screen,
A ceramic paste measuring 8 mm x 9 mm x about 15 μm and having the same ceramic composition as Green Route 4 is printed as shown in FIG.

After drying, soak in 20ml of 20% hydrochloric acid solution to completely dissolve unnecessary nickel foil, dry, and add 30ml of nickel foil on top.
50mm x 50mm by 0mm stainless steel screen
Mark 1i1 with ceramic paste of mm x about 15 μm,
Dry to obtain the first layer.

2nd layer] For the even-numbered layers after 21, print the ceramic paste one side from the first ceramic paste printing position, for example, by shifting 1 mm downward in Figure 5, and print the ceramic paste for the odd-numbered layers at the same level as the first layer. After printing on the position and laminating 10 layers in total, apply the above 1 layer with adhesive to the green sheet 4
The same green sheet was attached to the table.

The sample thus obtained was set in a mold and heated at about 80°C and 130kg/cm2 for 30 minutes using a hot press.
After the min treatment, it was allowed to cool and was cut as shown in FIG.

After that, the binder was removed at 550°C for 1 hour, and the
Sintered 45m1n at 150℃, applied external electrode to the end surface,
After baking, the lead wires were soldered and the conductivity between the terminals was measured.

As a result, the conductivity 1"i ratio was the average value (n-25
), indicating excellent conductivity.

〔Effect of the invention〕

According to the present invention, iron, nickel, and inexpensive metal foils can be used as internal electrodes, and internal electrodes with uniform thickness and excellent conductivity can be obtained, and the performance is excellent and the overall It is possible to reduce costs as a result.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a multilayer ceramic capacitor; Figure 2 is a cross-sectional view of a multilayer ceramic capacitor;
Figures 3 and 4 are explanatory diagrams showing the molding process, and Figure 5 is marked j.
FIG. 2 is a plan view of a derivative subjected to σ11. 1 is a ceramic dielectric, 2 is an internal electrode, 3 is an external electrode,
4 is a green sheet, 5 is a metal foil. Applicant: Komatsu Seisakusho Co., Ltd. Agent: Patent attorney: Akira Yonehara Patent attorney: Hamamoto, 1 Mai Figure 1 Figure 2 Figure 3 Figure 4 Sasa 5 times

Claims (1)

[Claims] In a laminate consisting of a dielectric and internal electrodes, a sheet of metal foil is bonded onto the dielectric, the necessary parts of the metal foil are masked with the dielectric, and then unnecessary parts of the metal foil are etched, Furthermore, a dielectric material is laminated on the entire surface including the etched portion, and each step is sequentially repeated a necessary number of times.