JPH04215414A - Manufacture of laminated ceramic electronic part - Google Patents

Abstract

PURPOSE:To obtain formations having a uniform forming density by forming recessions beforehand at parts of a green sheet where patterns are to be printed, in order to prevent stepped parts from being produced between the green sheet and patterns after the drying of the green sheet, and by printing the patterns on these recessions. CONSTITUTION:A slurry 13 composed of ferrite powder and an organic vehicle is painted on a base film 11 by a doctor blade method. Next, through holes 2 for the connection between layers are cut at specified positions of a green sheet 1 exfoliated from the drying-processed base film 11. And, paste for conductor patterns 3 is printed by using a screen printer on the recessions of the green sheet 1 formed by the protrusions 12 of the base film. Chiplike formations are obtained by laminating a printed green sheet segment and an unprinted green sheet and attaching to each other with pressure, and by cutting. After the chiplike formations are baked following that, external electrode paste is applied and baked, and Ni plating and solder plating are performed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing multilayer ceramic electronic components.

0002

[Prior Art] Multilayer ceramic electronic components include multilayer chip inductors, multilayer ceramic capacitors, LC chip components, LCR chip components, etc., and their manufacturing methods are shown in perspective view in FIG. 3, which shows an overview of the steps of the manufacturing process. The explanation will be as follows with reference to the drawings.

That is, after drilling a through hole 2 at a predetermined position in a green sheet piece 1 obtained by cutting a dielectric ceramic green sheet or a ferrite green sheet into an appropriate size, a through hole 2 is formed at a predetermined position of the green sheet.
A conductor pattern 3 for internal electrodes or coils is printed using a conductor paste mainly composed of g (Fig.
(See the exploded view of stacking shown in Figure f)), these are laminated and crimped to form a laminate 4 (see Figure (b)), and then the crimped laminate is cut and separated into each chip 5 (see Figure (b)). c). The exploded view in FIG. 2(f) illustrates the conductor pattern formed on each chip after cutting the laminate.

Next, these chips are fired to form a fired body 6.
(see figure (d)), external electrodes 7 for connection terminals are formed by baking on the ends of the element body, and if necessary, the external electrodes are plated to complete the chip component (see figure (e)). .

[0005] All parts produced in this way include a crimping process, and in the crimping process, the parts where electrodes are printed overlap each other, and the parts where electrodes are not printed overlap each other. has been done.

[0006]

[Problem to be solved by the invention] In the conventional manufacturing method,
As shown in FIGS. 4(a) to 4(c), green sheet piece 1
The internal electrode conductor pattern 3 formed on the top is shown in FIG.
As can be seen in the figure, since the green sheets are concentrated in a specific position, that is, the position shown surrounded by the two-dot chain line, during lamination pressure bonding, a region 8 is created in which the molding density of the green sheet is higher in that part than in other parts. When the element body of the chip 5 obtained from such a laminated molded body is fired, the balance of shrinkage during firing deteriorates, and cracks 9 occur near the conductor pattern 3, and stress 10 (arrow in the figure (c)) ) may remain. Cracks deteriorate the reliability (heat cycle, heat resistance, bending strength, etc.) of electronic components such as inductors, and stress reduces, for example, the inductance and Q of the inductor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a highly reliable manufacturing method for laminated ceramic electronic components in which the above-mentioned areas of high compaction density that occur in the laminated molded product produced by the compression bonding process of conventional manufacturing methods are not formed. Our goal is to provide the following.

[0008]

[Means for Solving the Problems] Therefore, in order to achieve the above object, the inventor of the present invention, as a result of research, formed recesses in a ceramic green sheet on which internal electrode portions are formed, and applied a conductive paste to the recesses. The inventors have discovered that by doing so, it is possible to make the degree of crimping uniform when crimping the green sheet, and that the factors that affect the reliability of electronic components mentioned above can be eliminated, and the present invention has been achieved.

Therefore, in the present invention, a conductive pattern or a coil pattern is printed using a conductive paste on a dielectric ceramic green sheet or a ferrite magnetic green sheet, and after these are laminated and pressed to form a molded body,
In a method for manufacturing multilayer ceramic electronic components, which involves cutting the green sheet into chip shapes, drying and firing the obtained molded body to form a chip element, and forming connection terminal electrodes on the ends of the chip element, the green sheet after drying is Manufacturing of a multilayer ceramic electronic component characterized in that a recess is formed in advance in the part of the green sheet where the pattern is printed, and the pattern is printed in the recess so as to eliminate the difference in level between the sheet and the pattern. The present invention provides a method.

[0010] In the method of the present invention, the portion of the green sheet where the conductor pattern for internal electrodes is to be printed is indented in advance, and a conductive paste is printed in the indentation, thereby eliminating the level difference after drying. Providing such concave portions in the green sheet can be achieved by applying a ferrite slurry or the like by, for example, a doctor blade method onto a base film having convex portions that match the printing pattern described above during production of the green sheet.

[0011]

[Function] Since the top surface of the green sheet after printing the conductor pattern becomes almost flat, there is no concentration of pressure during crimping, and a molded body with uniform density can be obtained, and this molded body will not shrink during firing. Because of the good balance, there is no occurrence of cracks or stress in the chip element.

The present invention will be further explained below with reference to Examples.

[0013]

[Example] First, Fig. 2 (a) (cross-sectional view) and (b) (
Prepare a base film for coating as shown in the plan view). The base film having such convex portions 12 can be obtained by a method such as continuous pressure bonding with a roll having concave portions matching the printing pattern, but the method is not limited.

FIG. 1 is a cross-sectional view showing the procedure of applying a slurry to the base film as described above by a doctor blade method and printing a conductive paste according to the method of the present invention, and 14 in FIG. Doctor blade, arrow indicates the direction of travel of the base film. That is, a slurry 13 made of ferrite powder and an organic vehicle is applied onto the base film 11 by a doctor blade method. The composition of the ferrite powder is Fe2O3 50 mol%,
A material consisting of 20 mol % of NiO, 20 mol % of ZnO, and 10 mol % of CuO was used, and an organic vehicle consisting of polyvinyl butyral resin, toluene, and ethanol was used. The coating method used was the doctor blade method, but a leveling coater with a post-metering system was used.
r), other methods may be used.

[0015] Next, through holes 2 for making connections between layers were made with a mold at predetermined locations in the green sheet 1 which had been dried and peeled off from the base film 11 (see Fig.
b) and (c)).

A screen printer was used to print paste for the conductor pattern 3 on the concave portions of the green sheet 1 formed by the convex portions 12 of the base film (FIG. 1(d)).
reference). The paste consists of Ag powder, ethyl cellulose, and a solvent.

The printed green sheet pieces and the unprinted sheet were laminated, pressed and cut in accordance with the conventional procedure explained above with reference to FIG. 3 to obtain a chip-shaped molded body. The pressure bonding conditions were 100°C and 250kg/cm2.

[0018] Next, the chip-shaped molded body was heated at 900°C for 1
After baking for an hour, apply external electrode paste and heat to 800℃.
Burnt with. The external electrode paste was mainly composed of Ag, and the external electrode was further plated with Ni and solder.

As described above, a multilayer chip inductor based on the method of the present invention was obtained, and FIGS. 5(a), (b) and (c)
) shows an exploded cross-sectional view of the lamination, a cross-sectional view of the chip body after lamination and pressure bonding, and a cross-sectional view after firing, and the compacting density of the compact was constant, and no cracks or stress were observed in the fired compact.

A comparative test was conducted on a conventional multilayer chip inductor and a multilayer chip inductor produced by the method of the present invention. The results were as shown in the table below.

[0021]

[0022]

[Effects of the Invention] As explained above, according to the method of the present invention, the top surface of the green sheet after printing becomes almost flat, so that no cracks occur during shrinkage during chip element firing, thereby increasing the reliability of the product. Since the inductance is high and there is no stress generated around the printed pattern, a product with higher inductance and Q can be obtained compared to conventional products with the same structure.

[Brief explanation of the drawing]

FIGS. 1A to 1D are cross-sectional views showing a procedure for printing conductive paste on a green sheet in an embodiment of the present invention.

FIG. 2 shows a base film used in the method of the present invention, with (a) being a cross-sectional view and (b) being a plan view.

FIGS. 3(a) to 3(f) are perspective views showing an outline of the manufacturing process of a conventional multilayer ceramic electronic component.

FIG. 4(a) is an exploded cross-sectional view of green sheets laminated in a conventional manufacturing process, (b) is a cross-sectional view of a molded body after lamination and pressure bonding, and (c) is a cross-sectional view of a chip element after firing.

FIG. 5 (a) is an exploded cross-sectional view of the lamination of the green sheet in the manufacturing process of the present invention, (b) is a cross-sectional view of the molded body after lamination and pressure bonding, and (c) is a cross-sectional view of the chip element after firing. .

[Explanation of symbols]

1. Green sheet piece 2.Through hole 3. Conductor pattern 4. Laminated body 5. Chip 6. Fired body 7. External electrode 8. Area with high molding density 9. Crack 10... Stress １１‥‥Base film 12.Protrusions on the base film 13. Slurry １４‥‥Doctor Blade

Claims (1)

[Claims] Claim 1: A conductive pattern or a coil pattern is printed on a dielectric ceramic green sheet or a ferrite magnetic green sheet using a conductive paste, and these are laminated and pressed to form a molded body, which is then cut into a chip shape. The molded body is dried and fired to form a chip element,
In a method for manufacturing a multilayer ceramic electronic component comprising forming connection terminal electrodes at the ends of the green sheet, the portion of the green sheet where the pattern is printed so as to eliminate the level difference between the green sheet and the pattern after drying. 1. A method for manufacturing a multilayer ceramic electronic component, comprising forming a recess in advance in the recess, and printing the pattern on the recess.