JPS62261114A - Laminated ceramic capacitor and manufacture of the same - 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 multilayer ceramic capacitor and a method for manufacturing the same, and more particularly to the structure of a capacitance adjusting electrode formed on the surface portion of a capacitor element and the method for manufacturing the same.

[Conventional technology]

Generally, a conventional multilayer ceramic capacitor having capacitance adjusting electrodes is formed by the steps shown in FIGS. 5 to 8. First, as shown in FIG. 5, after kneading a finely sized ceramic powder and an organic binder, a green sheet is produced by a doctor blade method. Next, this sheet is cut into a desired area, and a raw sheet 1 with internal electrodes 11 coated and dried by screen printing on one side of the surface, and a raw sheet 7 with capacitance adjustment electrodes 12 coated and dried. prepare. Next, the raw sheet 1 on which the internal electrodes 11 are printed is sandwiched between the top and bottom of the protective layer 2 made of raw shift without printing the electrodes.
After stacking the desired number of sheets, capacitance adjustment electrode 1 is placed on the top layer.
The raw sheets 7 formed with 2 are stacked in the same way to form a laminate 8 as shown in FIG. 6, which is bonded under heat and then cut into individual pieces as shown in FIGS. 7(a) to (c). Laminated raw chip pieces 9 are formed. In FIGS. 7(a) to (c),
Fig. 7(a) is a perspective view of an individual raw chip, Fig. 7(b) is a sectional view taken along dd' of Fig. 7(a), and Fig. 7(c) is a sectional view taken along ee-e.
'This is a cross-sectional view. This green chip piece 9 is fired, and terminal electrodes 5 are baked on both ends to produce a multilayer ceramic capacitor 20 having capacitance adjusting electrodes as shown in FIG.

[Problem that the invention seeks to solve]

In the multilayer ceramic capacitor 20 having the capacitance adjustment electrode described above, since the capacitance adjustment electrode 12 is exposed on the surface, the test terminal 13 and the capacitance adjustment electrode are separated from each other during the inspection process in the manufacturing process as shown in FIG. If the positional relationship between the electrodes 12 is poor, a short circuit will occur between the terminal electrode 5 and the capacitance adjustment electrode 12, making inspection impossible. Further, as shown in FIG. 10, when the capacitance adjustment electrode 12 is mounted on the land 1 of the printed wiring board 15,
4, the capacitance adjustment electrode 12 can only be set on one side of the capacitance adjustment multilayer ceramic capacitor 20, and care must be taken to ensure that the capacitance adjustment electrode 12 faces upward during mounting.

The purpose of the present invention is to enable efficient inspection during the manufacturing process, to enable capacitance adjustment electrodes to be disposed on both the upper and lower surfaces of a multilayer ceramic capacitor for capacitance adjustment, and to enable capacitance adjustment even when disposed on one surface during mounting. It is an object of the present invention to provide a multilayer ceramic capacitor and a method for manufacturing the same, which can reduce mounting costs without the need to take care that adjustment electrodes face upward.

[Means for solving problems]

The multilayer ceramic capacitor according to the first aspect of the present invention includes a first raw sheet formed by stacking one or more raw sheets provided with internal electrode patterns, and a second raw sheet consisting of only protective insulating layers above and below the first raw sheet. The present invention is constructed by providing at least one electrode pattern for capacitance adjustment near the bottom of the outermost layer surface of a multilayer ceramic capacitor element in which green sheets of No. 2 are laminated.

Further, the method for manufacturing a multilayer ceramic capacitor according to the second aspect of the present invention includes the steps of kneading fine ceramic powder and an organic binder and forming a green sheet 1 through a doctor blade method, and one side of the green sheet. A step of forming an internal electrode sheet 1- having an internal electrode pattern by screen printing and a capacitance adjustment sheet having an electrode pattern for capacitance adjustment, and forming protective layers on top and bottom of the internal electrode sheet with the internal electrode sheet in the center. After arranging the green sheet, the method includes the step of arranging the capacity adjusting sheet, and the step of further arranging an upper protective layer as the outermost layer.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. 1 to 4 are perspective views and cross-sectional views shown in order of steps to explain the structure and manufacturing method of one embodiment of the present invention.

First, as shown in FIG. 1, after kneading fine ceramic powder and an organic binder, a green sheet is produced by a doctor blade method. Next, this green sheet was cut into a desired area, and internal electrodes 11 were applied to one side of the surface by screen printing and dried. -1 and a raw sheet 7 on which the capacitance adjusting electrode 12 is adhered and dried are prepared. Next, the desired number of raw sheets 1 with internal electrodes 11 printed on them are sandwiched between upper and lower protective layers 2 made of raw sheets 1- with no electrodes printed on them, and then the internal electrodes 12 are applied. 7 is similarly stacked on the dried green sheet 1, and a desired number of upper protective layers 6 are stacked on the outermost layer so that the thickness after firing is 10 μm to 50 μrn, to form a laminate 3 as shown in FIG. Then heat and press.

Next, as shown in FIGS. 3(a) to 3(c), individual raw chips 4 are formed by cutting into individual pieces and stacking them. In addition,
Fig. 3(a) is a perspective view of an individual raw chip, Fig. 3(b) is a sectional view taken along line bb' of Fig. 3(a>), and Fig. 3(c) is a
It is a sectional view taken along the line -c'.

Next, this raw chip piece 4 is fired, and terminal electrodes 5 are attached to both ends.
When baked, the multilayer ceramic capacitor 10 of the present invention
is completed.

In such a case, a first raw sheet 1 made by stacking one or more raw sheets provided with internal electrode patterns 11 and a second raw sheet 2 made of a protective insulating layer are laminated above and below the first raw sheet 1. A multilayer ceramic capacitor is obtained in which at least one electrode pattern for capacitance adjustment is provided near the surface of the outermost layer of a multilayer ceramic capacitor element.

In addition, if the main protective layer in the multilayer ceramic capacitor 10 for capacitance adjustment is thicker than 50 μm, the energy used when trimming the capacitance adjustment electrode 12 using a laser or the like is too large, causing the dielectric to change in quality and resulting in a decrease in insulation resistance. . Moreover, if it is thinner than 10 μm, it becomes difficult to form and handle the raw sheet, causing manufacturing problems.

〔Effect of the invention〕

As explained above, by providing a thin dielectric material of a predetermined thickness on the capacitance adjustment electrode, the present invention enables efficient inspection during the manufacturing process in the same manner as conventional multilayer ceramic capacitors. Therefore, the capacitance adjustment electrodes can be disposed on both the upper and lower surfaces of the capacitance adjustment multilayer ceramic capacitor. For this reason, there is no need to take care that the capacitance adjustment electrode faces upward in order to avoid short-circuiting at the land of the board during mounting, which has the effect of reducing mounting costs.

[Brief explanation of drawings]

1 to 4 are perspective views and cross-sectional views shown in the order of steps to explain the structure and manufacturing method of one embodiment of the present invention, and FIG. 1 is an exploded perspective view showing the laminated structure during thermocompression bonding. Figures 2 and 2 are cross-sectional views taken along line a-a' of the laminate shown in Figure 1 after thermocompression bonding, and Figures 3 (a) to (c) are perspective views of individual green chips separated along the broken lines in Figure 2. Fig. 4 is a perspective view of a multilayer ceramic capacitor with terminal electrodes formed at both ends as shown in Figs. 3(a) to (C);
5 to 8 are perspective views and cross-sectional views shown in order of steps to explain the structure of a conventional multilayer ceramic capacitor and its manufacturing method, and FIG. 9 is an example of an inspection process of a conventional multilayer ceramic capacitor. FIG. 10 is a cross-sectional view showing the positional relationship between the terminal and the capacitance adjusting electrode, and FIG. 10 is a cross-sectional view showing the positional relationship between the capacitance adjusting electrode and the land of the printed wiring board when a conventional multilayer ceramic is mounted on the printed wiring board. DESCRIPTION OF SYMBOLS 1... Raw sheet, 2... Protective layer, 3.8... Laminated body, 4.9... Raw chip piece, 5... Terminal electrode, 6
... Main protective layer, 1, 20 ... Multilayer ceramic capacitor, 7 ... Electrode raw sheet for capacitance adjustment, 11 ...
Internal electrode, 12... Capacity adjustment electrode, 13... Inspection terminal, 14... Land, 15... Printed wiring board. : (Patent Attorney Susumu Uchihara) 1 Presentation; 1 m Place 2 Figure 5 Figure 6 Figure 8 Figure 9

Claims (3)

[Claims] (1) A multilayer ceramic capacitor in which a first green sheet is a stack of one or more green sheets provided with an internal electrode pattern, and a second green sheet consisting of only a protective insulating layer is laminated above and below the first green sheet. A multilayer ceramic capacitor characterized in that at least one electrode pattern for capacitance adjustment is provided near the bottom of the surface of the outermost layer of the element. (2) The multilayer ceramic capacitor according to claim (1), wherein the distance between the surface of the outermost layer and the electrode pattern for capacitance adjustment near the bottom of the surface of the outermost layer is 10 μm or more and 50 μm or less. (3) A step of kneading fine ceramic powder and an organic binder to form a raw sheet using a doctor blade method, and a sheet for internal electrodes having an internal electrode pattern by screen printing on one side of the raw sheet, and a sheet for capacity adjustment. A step of forming a capacitance adjustment sheet having an electrode pattern of A method for manufacturing a multilayer ceramic capacitor, further comprising the step of disposing an upper protective layer as the outermost layer.