JP3094926B2 - Manufacturing method of multilayer ceramic electronic component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a multilayer ceramic electronic component such as a multilayer ceramic capacitor used in various electric devices such as an electronic tuner of a television passive device, a video tape recorder, and a video camera. It is about.

[0002]

2. Description of the Related Art A method for manufacturing a multilayer ceramic capacitor which is one of multilayer ceramic electronic components is disclosed in Japanese Patent Publication No. 4-70.
As shown in, for example, Japanese Patent No. 765, it is generally as follows.

[0003] First, an organic binder, a plasticizer, a solvent, and the like are added to a ceramic mixed raw material containing barium titanate as a main component, mixed, and a slurry is formed. Make a sheet. This sheet is cut into an appropriate size, and while laminating, a palladium paste is screen-printed to form internal electrodes, pressed and cut to obtain individual laminates before firing. Thereafter, the laminate is dried for the purpose of removing a part of the organic matter of the laminate before firing, and the laminate, zirconia as an abrasive and water are sealed in a pot, and chamfering is performed for an appropriate time.
After chamfering, the laminate and the abrasive are separated, washed and dried. Chamfering is a process of smoothing the corners of the multilayer body in order to prevent cracks generated in the multilayer ceramic capacitor due to stress generated when the multilayer ceramic capacitor is mounted on a printed circuit board. Also, the removal of a part of the organic matter of the laminate is performed by imparting appropriate hardness to the laminate before firing, making it easier to scrape off the corners of the laminate with a polishing agent in a wet manner, and at the same time, chamfering and drying the laminate. It has the meaning of preventing sticking. Next, a binder is removed, and baked at a temperature of 1200 ° C. to 1400 ° C., a metal such as silver is baked at 900 ° C. as an external electrode on the exposed surface of the internal electrode, and plating is performed so as to cover the external electrode. Reach.

[0004]

According to this method, in the chamfering step, since a part of the organic component is removed and the chamfering is performed by a wet method, the inside of the laminate is easily impregnated with moisture during the chamfering. Since the water remains after drying, the water is rapidly scattered in the debubbling and firing steps, and structural defects are easily generated inside the sintered body. A sintered body having a structural defect therein is defective and has a problem of lowering the yield. Further, since the chamfering step includes three steps of a step of removing a part of the organic components of the laminate, a step of performing a wet beveling, and a drying step after the chamfering, the time required for the chamfering step is long. It also has the problem of being too long. SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a chamfering process that can prevent the occurrence of structural defects inside a sintered body and that simplifies the process.

[0005]

According to the present invention, there is provided a chamfering process in which a medium comprising a laminate, a ceramic powder, and a resin is placed in a container equipped with an organic lining and stirred. Rather than scraping off the corners of the laminate with an abrasive material as in the past, it is possible to strike the laminate against the lining and cut off the corners by the impact and remove some organic substances This step is not only unnecessary, but also can prevent the intrusion of moisture into the inside of the laminate, so that the above object can be achieved.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a laminated body in which ceramic layers containing barium titanate as a main raw material and an organic material and an internal electrode layer are alternately laminated. A first step of obtaining, a second step of chamfering the laminate in a wet manner, a third step of drying the laminate, and a fourth step of firing the laminate. In the method for manufacturing a laminated ceramic electronic component provided with the above, the second step of the chamfering is performed by putting the laminated body, a medium composed of ceramic powder and a resin in a container equipped with an organic lining, and stirring. This is a method for manufacturing a multilayer ceramic electronic component, characterized by preventing occurrence of structural defects inside a sintered body and simplifying a chamfering step.

According to a second aspect of the present invention, there is provided the method for manufacturing a multilayer ceramic electronic component according to the first aspect, wherein zirconia is used as the ceramic powder and polyester is used as the resin. Even if it wears and the abrasion powder adheres to the laminate and reacts with the ceramic during firing, it is possible to suppress adverse effects on the electrical characteristics.

According to a third aspect of the present invention, the hardness of the lining is larger than the hardness of the laminate.
The method for manufacturing a multilayer ceramic electronic component according to the item (1), wherein a laminate having a desired shaving degree can be obtained.

[0009] The invention described in claim 4 is a rubber hardness of 20
The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein the organic material having the above hardness is used for the lining, and a laminate having a desired degree of shaving can be obtained.

The invention according to claim 5 is characterized in that, as the organic substance,
5. The method for producing a multilayer ceramic electronic component according to claim 4, wherein one of neoprene rubber, urethane rubber and special natural rubber is used, and the lining wears during a chamfering step, and the wear powder is produced. Even if adhered to the laminate, it is decomposed in the binder removal and firing steps, so that it is possible to suppress adverse effects on electrical characteristics.

[0011] The invention according to claim 6 is characterized in that after the chamfering step,
2. The multilayer ceramic electronic device according to claim 1, wherein the laminate is put into a container having air permeability, and while the pressure is reduced in one direction, warm air is sent from another direction to dry the laminate. 3. This is a method for manufacturing a component, in which moisture on the surface of the laminate flows out in a direction in which the pressure is reduced, and the surface of the laminate can be dried.

According to a seventh aspect of the present invention, there is provided the method for manufacturing a multilayer ceramic electronic component according to the fifth aspect, wherein the temperature of the hot air is set to be equal to or lower than the softening point of the binder contained in the laminate. Sticking between the laminates can be suppressed.

An embodiment of the present invention will be described below with reference to the drawings, taking a multilayer ceramic capacitor as an example.

(Embodiment 1) In this embodiment,
1 is a cross-sectional view showing a state of a chamfering process, FIG. 2 is a process diagram showing a method for manufacturing a multilayer ceramic capacitor, FIG. 3 is a cross-sectional view of a container used for chamfering, and FIG. FIG. 5 and FIG. 5 are perspective views of a basket used for drying after chamfering, and FIG. 6 is a perspective view showing a flow of warm air during drying.

First, 100 parts by weight of a ceramic mixed raw material containing barium titanate as a main component, 7 parts by weight of a polyvinyl butyral resin having a softening point of 87 ° C. as a binder, 2 parts by weight of dibutyl phthalate as a plasticizer, and 50 parts by weight of butyl acetate as a solvent Then, after mixing and mixing to form a slurry, a ceramic sheet having a thickness of 30 μm is prepared by using a doctor blade method. Next, this ceramic sheet is cut into an appropriate size, and a step of screen-printing a palladium paste while laminating to form internal electrodes is repeated,
Crimped and cut, 3.6 vertical ceramic layers consisting of 30 layers
A laminate of mm × 1.8 mm in width is prepared (20 in FIG. 2). Next, as shown in FIG. 3, a cylindrical container 10 having a lining 1 made of urethane rubber and having a diameter of 150 mm and a height of 200 mm is prepared, and a spherical medium made of zirconia and polyester having a diameter of 5 mm is prepared for 2,000 laminated bodies. In a container 10 together with 100 cc and 500 cc of water. FIG. 1 is a view showing the movement of the laminate 2, the medium 3 and the water 4 inside the container 10 when the container 10 is rotated at a high speed using a centrifugal planetary mill. The medium 3 collides with the laminate 2 in water (pure water) 4, and the laminate 2 collides with the lining 1 of the container 10. Here, the medium 3 has a function of imparting acceleration to the laminate 2 when the laminate 2 collides with the lining 1, and a desired shaving degree is obtained by adjusting the size and the amount of the medium 3 to be enclosed. Can be. At this time, since the hardness of the laminate 2 is smaller than that of the lining 1, the corners of the laminate 2 are cut.
A desired degree of shaving can be obtained by selecting the hardness of the lining 1.

A desired amount can be removed by chamfering for 5 to 10 minutes (21 in FIG. 2). Thereafter, the laminate 2, the medium 3, and the water 4 are separated. FIG. 4 shows the laminate 2 after wet chamfering, and the corners 5 are rounded. Next, as shown in FIG.
A laminated basket 2 having air permeability of 1 mm is prepared, the laminate 2 is sealed, and as shown in FIG. 6, warm air is sent from the upper part of the car 6 and sucked by a blower from the lower part to form a surface of the laminate 2. The water is dried (22 in FIG. 2). The temperature of the warm air at this time was set at 20 ° C., 40 ° C., 60 ° C., 80 ° C., and 100 ° C., and the laminate 2 was debindered at 400 ° C. (23 in FIG. 2) and fired at 1300 ° C. (See 2 in Fig. 2)
4). Next, external electrodes are formed (25 in FIG. 2) and plated (26 in FIG. 2) to obtain a multilayer ceramic capacitor. (Table 1) shows the number of sticks between the laminates for 1000 laminated bodies after drying, and (Table 2) shows the number of internal structural defects generated for 50 sintered bodies.

[0017]

[Table 1]

[0018]

[Table 2]

For comparison, a case where chamfering is performed by a conventional method is also described and shown.

As is clear from Table 1, sticking between the laminates 2 does not occur at a drying temperature of 80 ° C. or lower, which is lower than the softening point of the binder. The sticking of the laminates 2 occurs when the binder contained in the laminates 2 is softened in the drying step and the softened organic matter on the surface of the laminates 2 is generated. In the present invention, the laminate 2 before drying is placed in the basket 6
In order to force hot air from the other side while reducing the pressure in one direction of the car 6, the surface is sufficiently dried even if the temperature of the hot air is lower than 20 ° C. Therefore, it is preferable to use a binder having a softening point of 20 ° C. or higher from the viewpoint of suppressing the sticking of the laminate 2.

As is clear from Table 2, it can be said that the present embodiment can prevent the occurrence of structural defects.

Accordingly, the present invention eliminates the step of removing a part of the organic components of the laminate which has been conventionally performed, and removes the sintered body caused by the impregnation of moisture into the laminate in the wet chamfering step. In addition to preventing the occurrence of structural defects, the chamfering step consists of two steps: a step of wet-chamfering the laminate and a drying step after the chamfering, thereby shortening the time required for the chamfering step. it can.

In this embodiment, urethane rubber is used as the lining of the chamfered container, but the same effect can be obtained by using a rubber having a rubber hardness of 20 or more and an organic substance which decomposes in the binder removal and firing steps. . For example, special natural rubber or neoprene rubber.

[0024] Further, as for the medium, even if the abrasion powder generated during the chamfering step and the laminated body react during firing, the ceramic powder and the resin can suppress the adverse effect on the electrical characteristics. The same effect can be obtained by using a conical shape instead of a spherical shape.

[0025]

As described above, according to the present invention, the step of removing a part of the organic components of the laminate which was conventionally required is eliminated, and the inside of the laminate is impregnated with moisture by wet chamfering. In addition to suppressing the structural defects inside the sintered body that occur, the chamfering process consists of two processes: a wet process for the laminate and a drying process after the chamfering, shortening the time required for the chamfering process In addition, since it is possible to prevent the intrusion of moisture into the inside of the laminate, a great effect is brought about as compared with the conventional method.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a chamfering step of a multilayer ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of the multilayer ceramic capacitor according to one embodiment of the present invention.

FIG. 3 is a sectional view of a container used for chamfering according to an embodiment of the present invention.

FIG. 4 is a perspective view of the laminated body after chamfering in one embodiment of the present invention.

FIG. 5 is a perspective view of a basket used for drying after chamfering in one embodiment of the present invention.

FIG. 6 is a perspective view showing a flow of hot air during drying in one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lining 2 Laminated body 3 Medium 6 Basket 10 Container

Continuation of front page (56) References JP-A-4-300159 (JP, A) JP-A-4-142722 (JP, A) JP-A-2-101725 (JP, A) JP-A-2-101724 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 4/00-4/40 H01G 13/00-13/06

Claims (7)

(57) [Claims] 1. A first step of obtaining a laminate in which a ceramic layer mainly containing barium titanate as a main raw material and a ceramic layer having an organic substance and an internal electrode layer are alternately laminated, A method of manufacturing a multilayer ceramic electronic component, comprising: a second step of chamfering in a wet manner, a third step of drying the laminate, and a fourth step of subsequently firing the laminate. The second step is a method of manufacturing a multilayer ceramic electronic component, wherein the laminate and a medium made of a ceramic powder and a resin are placed in a container equipped with an organic lining and chamfered by stirring. . 2. The method according to claim 1, wherein the ceramic powder uses zirconia and the resin uses polyester. 3. The method according to claim 1, wherein the hardness of the lining is greater than the hardness of the laminate. 4. The organic material used for the lining has a rubber hardness of 2
The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein the multilayer ceramic electronic component has a hardness of 0 or more. 5. The method according to claim 4, wherein the organic substance is one of neoprene rubber, urethane rubber and special natural rubber. 6. The drying step, wherein the laminate is charged into a container having air permeability, and hot air is sent from another direction while reducing pressure in one direction of the container.
3. The method for producing a multilayer ceramic electronic component according to item 1. 7. The method for manufacturing a multilayer ceramic electronic component according to claim 6, wherein the temperature of the hot air is equal to or lower than a softening point of a binder contained in the laminate.