JP2001023854A - Manufacture of multilayer ceramic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a multilayer ceramic capacitor having superior productivity. SOLUTION: In a process of manufacturing a laminated green block of a multilayer ceramic capacitor by alternately laminating a plurality of ceramic green sheets 2 and internal electrodes and by thermocompression-bonding them, a manufacturing method of the multilayer ceramic capacitor includes the step of forming an internal electrode on the surface of the continuous ceramic green sheet with a depression pattern and then forming a ceramic layer 8 to eliminate the difference in thickness between the portion, where the internal electrode is not formed and the portion where the internal electrode is formed, through the use of a projection pattern whose pattern is reverse to that of the internal electrode, to form an effective green sheet 7 having a flat surface; laminating a plurality of effective green sheets 7 and thermocompression-bonding them to form a laminated green block of the multilayer ceramic capacitor, and cutting this laminated green block to a predetermined chip form and firing it.

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 a multilayer ceramic capacitor.

[0002]

2. Description of the Related Art As electronic devices become smaller and lighter in recent years, multilayer ceramic capacitors are also required to be smaller and have larger capacities. The miniaturization and large capacity of the multilayer ceramic capacitor are dealt with by thinning the ceramic green sheet of the effective layer and by multi-layering. However, a stacked green block in which multiple thin ceramic green sheets are stacked has a large thickness step between a portion where an internal electrode is formed and a portion where an internal electrode is not formed. For this reason, there is a problem that the adhesiveness between the green sheets of the effective layer is reduced and delamination is easily generated inside the sintered body. As a countermeasure, it has been proposed to provide a ceramic layer on the surface of the ceramic green sheet on which the internal electrodes are formed to eliminate the thickness difference from the internal electrodes.

A conventional method for manufacturing a multilayer ceramic capacitor will be described below with reference to FIGS.

First, a ceramic green sheet 2 is formed by applying a ceramic slurry obtained by adding an organic binder or the like to barium titanate powder as a main component on a carrier film 1 by a gravure printing method or the like and then drying.

Next, an electrode paste containing a metal powder such as palladium as a main component is printed on one side of the ceramic green sheet 2 by a gravure printing method or the like, and then dried to form the internal electrodes 4.

Next, a ceramic slurry having the same composition as that of the ceramic green sheet 2 is applied to a portion of the ceramic green sheet 2 where the internal electrode 4 is not formed by a gravure printing method or the like using a pattern opposite to the pattern of the internal electrode 4. After forming the ceramic layer 8 for eliminating the thickness step from the electrode 4, it is dried to produce an effective layer green sheet 5 having a flat surface.

Thereafter, a ceramic slurry is applied to the surface of the effective layer green sheet 5 and dried, and printing and drying of the internal electrode 4 and the ceramic layer 8 are repeated to produce a multiple effective layer green sheet 7.

Next, a predetermined number of multiple effective layer green sheets 7 are laminated and pressed by heating to produce a laminated green block (not shown).

Next, after cutting the laminated green block into a predetermined green chip shape, the laminated green block is degreased and fired at a predetermined temperature and atmosphere to produce a sintered body of the laminated ceramic capacitor.

Thereafter, the sintered body is chamfered, and external electrodes (not shown) are formed on both ends where the internal electrodes are exposed, thereby completing a multilayer ceramic capacitor.

[0011]

In the above prior art,
It is extremely difficult to accurately form the ceramic layer 5 on the portion of the surface of the ceramic green sheet 2 where the internal electrode 4 is not formed, and it takes a long time to adjust the ceramic layer 5 and the productivity is reduced.
That is, when the internal electrode 4 is dried after the printing, the mechanical elongation for winding the ceramic green sheet 2 and the elongation at the time of drying occur to a considerable extent.

According to the present invention, a ceramic layer is accurately formed on a portion of a ceramic green sheet where no internal electrode is formed,
Easily produce an effective layer green sheet with a flat surface,
In addition, it is an object of the present invention to provide a method of manufacturing a multilayer ceramic capacitor having a high production efficiency by shortening the lamination time of the entire green sheet and the multilayer green block by using the effective layer.

[0013]

In order to achieve the above object, the present invention provides a method for producing a laminated green block of a laminated ceramic capacitor by alternately laminating a plurality of ceramic green sheets and internal electrodes by heat and pressure. After forming an internal electrode in an intaglio on the surface of the ceramic green sheet, then apply a ceramic layer that eliminates the thickness step from the internal electrode forming part using a relief of the internal electrode pattern and the reverse pattern on the part where the internal electrode is not formed After drying, an effective layer green sheet having a flat surface is produced, and the effective layer green sheet is repeatedly subjected to thermal compression bonding to produce a multiple effective layer green sheet and a laminated green block. By using this method, it is possible to easily laminate the effective layer green sheet and the laminated green block in which the internal electrodes and the ceramic layer are accurately formed in a continuous process, and achieve the intended purpose. Can be.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention is characterized in that a plurality of ceramic green sheets and internal electrodes are alternately laminated and heated and pressed to produce a laminated green block of a laminated ceramic capacitor. After forming the internal electrodes in the intaglio on the surface of the ceramic green sheet, a ceramic layer is formed on the non-formed portions of the internal electrodes by using a relief of the internal electrode pattern and the reverse pattern to eliminate the thickness step from the internal electrode formation portion. A step of preparing an effective layer having a flat surface, a step of heating and pressure-bonding the effective layer to form a laminated green block, and a step of cutting the laminated green block into a predetermined green chip shape,
Baking a monolithic ceramic capacitor comprising a step of continuously forming an internal electrode and a ceramic layer on a ceramic green sheet surface in a series of steps. It is possible to efficiently create a flat effective layer green sheet on which a ceramic layer that solves the above problem is accurately formed. The laminate green block formed by laminating the effective layer green sheets can eliminate the thickness step between the portion where the internal electrode is formed and the portion where the internal electrode is not formed, thereby preventing the occurrence of delamination of the sintered body and the laminate green block. The stacking time of the entire block can be shortened, resulting in high productivity.

According to a second aspect of the present invention, an internal electrode formed in an intaglio on the surface of a ceramic green sheet is not dried, and a relief pattern having an inverse pattern to the internal electrode pattern is continuously formed on a portion where no internal electrode is formed. 2. A method of manufacturing a multilayer ceramic capacitor according to claim 1, wherein a ceramic layer is formed using the method described above, and this is dried to produce an effective layer green sheet having a flat surface. Subsequently, to form the ceramic layer, the ceramic layer is precisely formed on the non-formed portion of the internal electrode without considering the mechanical expansion of the ceramic green sheet and the expansion and contraction of the dried ceramic green sheet and the internal electrode. , And can be easily formed.

According to the present invention, it is possible to easily control the formation positions of the internal electrodes and the ceramic layer by shifting the intaglio of the internal electrodes and the relief plate of the ceramic layer by a predetermined distance and adjusting the application position in advance. Green sheets can be efficiently produced.

According to a third aspect of the present invention, an intaglio plate having an internal electrode provided on the surface of a drum and a relief plate having a ceramic layer provided on the surface of the drum are used. 3. The method for manufacturing a multilayer ceramic capacitor according to claim 1 or 2, wherein when the internal electrode and the ceramic layer are continuously formed, the rotation of each of the drums is synchronized and the application is performed in advance. By performing the position adjustment, each of the internal electrode and the ceramic layer can be easily formed on the surface of the ceramic green sheet with high accuracy, and an effective layer green sheet having a flat surface can be efficiently produced.

According to a fourth aspect of the present invention, an effective layer green sheet having a flat surface on which an internal electrode and a ceramic layer are formed is provided so that the surface on which the internal electrode is formed and the ceramic green sheet surface are in contact with each other. Each of the plurality of layers is repeatedly heated and pressed by being alternately shifted by a predetermined dimension in the length direction of the internal electrode to produce a multi-layered green sheet, and then repeatedly laminated by heating the plurality of layers to produce a laminated green block. A method for manufacturing a multilayer ceramic capacitor according to any one of claims 1 to 3, wherein heating and lamination are repeatedly performed using an effective layer green sheet on which an internal electrode and a ceramic layer are accurately formed, thereby obtaining a multi-effective layer green. The lamination time of the entire sheet and laminated green block is shortened, and multilayer ceramic capacitors can be produced efficiently. That.

According to a fifth aspect of the present invention, the laminated thermocompression bonding of the multiple effective layer green sheets is performed by lowering the pressure by at least 20 kgf / cm ² or less than the laminating thermocompression bonding conditions of the laminated green block, or by heating. 5. The method for producing a multilayer ceramic capacitor according to claim 4, wherein the temperature is lowered by 20 ° C. or more, wherein the compression rate of the ceramic green sheet is reduced when producing the multi-layer green sheet, and the ceramic is produced when producing the laminated green block. Laminating conditions that can increase the compression ratio of the green sheet to improve the adhesion between multiple effective layer green sheets, and reduce the planar expansion of the multiple effective layer green sheet to prevent misalignment between the internal electrodes. It is specified.

According to a sixth aspect of the present invention, there is provided the method according to any one of the first to fifth aspects, wherein the laminating thermocompression bonding of the multi-effective layer green sheet and the laminated green block is performed in less than 2 seconds. The method for manufacturing a laminated ceramic capacitor according to the above, wherein the effective layer green sheet on which the internal electrodes and the ceramic layers are accurately formed is flat, so that the multi-effective layer green sheet and the laminate green block laminated using this are: The pressing force and heat are evenly transmitted in less than 2 seconds, and the two layers can be sufficiently adhered to each other, so that the lamination time of the entire laminated green block can be shortened, and a laminated ceramic capacitor can be efficiently produced.

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS.

First, a ceramic slurry is prepared by mixing predetermined amounts of a dielectric ceramic raw material powder containing barium titanate as a main component, an organic binder, a plasticizer, and an organic solvent, respectively. The ceramic slurry is applied thereon and dried to produce a ceramic green sheet 2 having a thickness of 25 μm and a width of 150 mm.

Next, on the surface of the ceramic green sheet 2 formed on the carrier film 1, an electrode paste mainly composed of nickel metal powder is used, and an internal electrode 4 having a thickness of 2 μm is formed by an intaglio drum 3 having an intaglio on the surface. Then, without drying the internal electrodes 4, the internal electrodes 4 are used by using a relief drum 9 having a relief pattern provided on the surface in a pattern opposite to that of the internal electrodes 4.
A ceramic slurry having the same composition as that of the ceramic green sheet 2 is applied to the non-formed portions, and a 2 μm thick internal electrode 4 is formed.
After forming a ceramic layer 8 for eliminating the step with the above, these are dried to produce an effective layer green sheet 5 having a flat surface.

The drums 3 and 9 are paired with a rubber roller 10 to provide a certain interval in series with the traveling direction of the ceramic green sheet 2 as shown in FIG. The ceramic layer 8 is arranged at a distance where excessive tension is not applied, and the rotation is synchronized so that the ceramic layer 8 does not overlap the internal electrode 4 formed earlier.

Since the drying process is not performed after the formation of the internal electrodes 4, the ceramic green sheet 2 and the internal electrodes 4 do not elongate due to the drying, so that the printing positioning of the internal electrodes 4 and the ceramic layer 8 is facilitated, and each of them is accurately formed. Can be formed.

It is desirable that the solvent of the electrode paste be incompatible with the binder component contained in the ceramic green sheet 2.

Next, while separating the effective layer green sheet 5 from the carrier film 1, the effective layer green sheet 5 formed on another carrier film 1 has a flat surface.
The sheet is sent between a pair of stainless steel pressure rollers 6 having a heating mechanism having a width of 200 mm and a diameter of 50 mm, and is laminated and pressure-bonded to produce a multi-layer green sheet 7 of two effective layer green sheets 5.

The multiple effective layer green sheets 7 are formed in such a manner that the internal electrodes 4 forming a pair overlap each other with a predetermined dimension therebetween with the ceramic green sheets 2 interposed therebetween, and are stacked in a staggered manner.

The conditions for producing the multi-layer green sheet 7 are as follows: the surface temperature of the pressure roller 6 is set at 20.degree.
The test was carried out at three points of ° C and three points of pressures of 10, 20, and 30 kgf / cm ² .

Further, a composite multi-effective layer (not shown) was prepared by laminating two, four and eight multi-effective layer green sheets 7 together.

Apart from the above, the ceramic green sheet 2
Is cut into a 150 mm square vertically and horizontally, and a predetermined number of these are laminated and heat-pressed to prepare an ineffective layer green sheet 11.

Then, as shown in FIG. 2, the multiple effective layer green sheet 7 and the composite multiple effective layer are vertically
After cutting to a square of mm, the laminated layer is repeatedly stacked and heated and pressed on the ineffective layer green sheet 11 until the internal electrodes 4 have 96 layers.
To form a laminate green block.

The lamination was performed such that the odd-numbered layers and the even-numbered layers of the internal electrode 4 overlapped each other in the laminating direction.

Further, as the laminating conditions, the green sheet 7 for multiple effective layers has a pressing force of 50 kgf / cm ² , a heating temperature of 100 ° C.,
The pressure bonding time was 0.5, 1.0, and 2.0 sec.

Next, after cutting the laminate green block into a predetermined green chip shape, following de-buying at 350 ° C. in the air, firing at 1300 ° C. in a non-oxidizing atmosphere in which nickel of the internal electrode 4 is not oxidized. Was done.

The green chip has a structure in which internal electrodes 4 are disposed on both end faces in the longitudinal direction with the ceramic green sheet 2 interposed therebetween and are exposed alternately at different end faces.

Next, external electrodes (not shown) were formed on both end surfaces of the sintered body where the internal electrodes 4 were exposed, thereby completing a multilayer ceramic capacitor.

The multiple effective layer green sheet 7 and the internal electrode 4 and the ceramic layer 8 of the composite multiple effective layer according to the first embodiment
And the time required to produce the multiple effective layer green sheet 7, the composite multiple effective layer and the laminated green block, and the delamination occurrence rate of the sintered body. The results are shown in Table 1).

It should be noted that the time required for the production was expressed as a ratio when the production time of the effective layer green sheet 5 and the multiple effective layer green sheet 7 produced by the conventional production method was set to 100.

The misalignment of the internal electrode 4 is determined by cutting the multiple effective layer green sheet 7 and the laminated green block in the longitudinal direction of the internal electrode 4 and overlapping the pair of internal electrodes 4 with the ceramic green sheet 2 interposed therebetween. The situation was observed with a stereoscopic microscope, and the delamination of the sintered body was polished in a direction perpendicular to the internal electrodes 4 and the peeling state between the internal electrodes 4 was observed with a stereoscopic microscope.

[0041]

[Table 1]

As shown in (Table 1), the multilayer ceramic capacitor manufactured by the manufacturing method of the present invention has a lower misregistration rate of the multiple effective layer green sheet 7 as compared with the conventional product, and the multiple effective layer green sheet It can be seen that the production time of the sheet 7 and the laminate green block is reduced.

This is because the conventional method forms the internal electrode 4 on the surface of the ceramic green sheet 2 and then forms the ceramic layer 8 through a drying process. This is because, due to the extension, the misalignment of the upper internal electrode 4 paired with the lower internal electrode 4 occurs, and it takes time to adjust the positioning of the ceramic layer 8.

However, in the composite multiple effective layer in which a plurality of multiple effective layer green sheets 7 are laminated, the misregistration of the internal electrode 4 tends to increase as the number of laminated layers increases. It seems that No. 7 expanded in the plane direction due to repeated heating and pressing.
Therefore, it is desirable that the composite multi-effective layer be limited to a stack of up to eight multi-effective layer green sheets 7.

In any case, no difference was observed in the incidence rate of delamination failure of the sintered body.

In the present embodiment, the internal electrodes 4 and the ceramic layers 8 are made of the drums 3 and 9 provided with intaglio and letterpress, respectively, on the surface, but this is not restrictive.

In the laminated green block, the internal electrodes 4 are made up of 96 layers.

Furthermore, in the present embodiment, the method of manufacturing a multilayer ceramic capacitor has been described, but it goes without saying that the present invention is also effective for other multilayer ceramic electronic components.

[0049]

As described above, according to the present invention, in a process of alternately laminating a plurality of ceramic green sheets and internal electrodes by heat and pressure to produce a laminated green block of a laminated ceramic capacitor, a continuous green sheet is formed on the surface of the ceramic green sheets. After forming the internal electrodes with the intaglio plate, a ceramic layer that eliminates the thickness difference from the internal electrode forming part is formed on the non-formed portions of the internal electrodes by using a relief pattern with the reverse pattern of the internal electrode pattern. A step of preparing a green sheet, a step of forming a laminate green block by heat-pressing a plurality of layers of the effective layer green sheet, and a step of cutting the laminate green block into a predetermined green chip shape and then firing. By using the method for manufacturing a multilayer ceramic capacitor having a It is possible to manufacture in time.

A multiple effective layer green sheet, which is produced by repeatedly laminating and pressing a plurality of the effective layer green sheets,
The laminated green block suppresses the occurrence of misalignment of the internal electrodes and shortens the time required for manufacturing the entire multilayer ceramic capacitor, thereby improving the productivity of the multilayer ceramic capacitor and improving the yield. This is an industrially effective means.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a method for producing a multiple effective layer green sheet of the present invention.

FIG. 2 is a schematic cross-sectional view of a method of manufacturing a multilayer green block of the multilayer ceramic capacitor.

FIG. 3 is a schematic cross-sectional view of a method for producing a multiple effective layer green sheet according to a conventional method.

[Description of Signs] 1 Carrier film 2 Ceramic green sheet 3 Intaglio drum 4 Internal electrode 5 Effective layer green sheet 6 Crimping roller 7 Multi-effective layer green sheet 8 Ceramic layer 9 Letterpress drum 10 Rubber roller 11 Invalid layer green sheet

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazumasa Konishi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5E001 AB03 AC03 AC09 AD03 AE02 AE03 AH01 AH05 AH06 AH09 AJ01 AJ02 5E082 AB03 BC33 BC38 EE04 EE23 EE35 EE41 FG06 FG26 FG27 FG51 HH43 LL01 LL02 LL03 LL35 MM21 MM22 MM24 PP05 PP06 PP07

Claims (6)

[Claims] 1. A step of manufacturing a multilayer green block of a multilayer ceramic capacitor by alternately laminating a plurality of ceramic green sheets and internal electrodes by heat and pressure.
After forming an internal electrode with an intaglio on the surface of the continuous ceramic green sheet, a ceramic layer that eliminates the thickness difference between the internal electrode forming part and the internal electrode pattern is formed in the part where the internal electrode is not formed by using a relief of the internal electrode pattern and the reverse pattern Then, a step of producing an effective layer green sheet having a flat surface, a step of heating and pressing the effective layer green sheet by a plurality of layers to produce a laminated green block, and forming the laminated green block into a predetermined green chip shape. Cutting and firing the laminate. 2. An internal electrode formed of an intaglio on the surface of a ceramic green sheet is formed without drying, and a ceramic layer is formed on a portion where no internal electrode is formed by using a relief of an internal electrode pattern and a reverse pattern. 2. The method for manufacturing a multilayer ceramic capacitor according to claim 1, wherein the green sheet is dried to produce an effective layer green sheet having a flat surface. 3. An intaglio plate having an internal electrode provided on the surface of the drum and a relief plate having a ceramic layer provided on the surface of the drum.
3. The method according to claim 1, wherein the internal electrode and the ceramic layer are continuously formed on the surface of the ceramic green sheet. 4. An effective layer green sheet having a flat surface on which an internal electrode and a ceramic layer are formed is alternately arranged by a predetermined size in the length direction of the internal electrode so that the surface on which the internal electrode is formed and the ceramic green sheet surface are in contact with each other. The multi-layered green sheet is repeatedly produced by repeating the multiple-layer heating / compression bonding by shifting to a multi-layered green sheet, and then the multi-layer heating and laminating is repeated to produce a laminated green block according to any one of claims 1 to 3. A manufacturing method of the multilayer ceramic capacitor according to the above. 5. The laminated thermocompression bonding of the multiple effective layer green sheets is performed by lowering the pressing force by at least 20 kgf / cm ² or lower by 20 ° C. or more than the lamination thermocompression bonding conditions of the laminated green block. A manufacturing method of the multilayer ceramic capacitor according to the above. 6. The method for producing a multilayer ceramic capacitor according to claim 1, wherein the lamination thermocompression bonding of the multi-effective layer green sheet and the laminated green block is performed in less than 2 seconds.