JPH0828138B2 - Method for manufacturing ceramic laminate - 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 for manufacturing a ceramic laminate.

[0002]

2. Description of the Related Art As a ceramic laminated body as an electronic component, there are a laminated ceramic capacitor, a laminated ceramic inductor, a laminated ceramic resistor, or a laminated ceramic composite component in which a plurality of these elements are integrated and integrated. As a typical example of such a laminated ceramic composite component, a laminated ceramic capacitor will be described in detail below.

A method of manufacturing a monolithic ceramic capacitor is as follows.
First, a dielectric ceramic raw material powder and an organic binder are mixed to form a slurry, which is formed into a long ceramic green sheet having a thickness of tens of μm by a slit casting method such as a doctor blade method or a reverse coating method.

On the green sheet, a rectangular internal electrode pattern of, for example, 6.0 mm × 0.8 mm is vertically and horizontally arrayed with a spacing of 1.0 mm by a screen printing method or a roll transfer method using a conductive paste such as Pd.

A plurality of sheets on which internal electrode patterns are formed are adjacent to each other, but the internal electrode patterns on the sheets do not substantially or at all deviate from each other in the width direction, but in the longitudinal direction, the pattern length is long. The predetermined number of bisectors in the direction are alternately staggered so that the bisectors of the internal electrode patterns on the adjacent sheet coincide with the bisectors of the intervals between the adjacent electrode patterns, and the patterns are not printed above and below the stack. A laminate obtained by stacking at least one green sheet is placed between two parallel flat plates of a press, and these flat plates are moved from above and below to press and press the green sheets.

When the above-mentioned ceramic sheet laminated body on which internal electrodes are formed and superposed is pressure-bonded by this apparatus, a portion where the internal electrodes of the superposed ceramic sheet groups are stacked and the internal electrode pattern are formed. On both sides of the, where the electrode pattern is not formed,
There is a difference in applied pressure. That is, the pressure applied to the ceramic sheet is high in the portion where the internal electrodes are stacked and is low in the portion where the internal electrodes are not stacked. Therefore, if the pressure is increased so that sufficient pressure is applied to the ceramic sheets to adhere to the portions where only the ceramic sheets are stacked, the pressure at the portion with the internal electrodes becomes too high and the internal electrode patterns are stretched. , Deteriorate the accuracy of the electrode pattern. Therefore, if the pressure is set so that the internal electrode pattern does not stretch, the pressure to the portion where only the ceramic sheets are stacked becomes low, and delamination may occur after firing the ceramic laminated body. In order to make the extension of the electrode pattern small and to prevent the peeling of the portion where only the ceramic sheets are stacked, the pressure force is determined and pressure-bonded in consideration of the balance between the two.
Then, after pressure-bonding the laminated body in this manner, a chip piece is formed by cutting the internal electrodes at equal intervals.
After firing this, a conductive paste was applied to the end face of the chip and baked to form external electrodes, thus manufacturing a monolithic ceramic capacitor.

[0007]

In the above conventional method,
There is a problem that the pressure is taken into consideration in consideration of the elongation of the electrode pattern of the internal electrode and the adhesive strength of the portion where the electrode pattern is not present, and further, the elongation of the electrode pattern cannot be eliminated after the lamination. Therefore,
An object of the present invention is to provide a method for manufacturing a monolithic ceramic capacitor in which uniform pressure is applied and the internal electrode pattern is not stretched.

[0008]

In order to solve the above problems, a conductive paste is applied onto a ceramic green sheet, and then the sheets are repeatedly stacked to stack a large number of sheets, and these sheets are pressure-pressed and laminated. A ceramic green sheet having different hardness is prepared as the ceramic green sheet in the method for producing a ceramic laminated body, which comprises forming a body, cutting the laminated body into chip pieces of a predetermined size, and firing. The conductive paste is applied on the ceramic green sheet of, and the conductive paste is not applied on the ceramic green sheet of lower hardness, and these hard and soft green sheets are alternately laminated and crimped, or One main surface of the sheet is a hard surface with high hardness, and the other main surface is a soft surface with low hardness. The conductive paste is applied only on a hard surface, it has developed a method for producing a ceramic laminate, characterized in that the green sheet and a hard surface and a soft surface for crimping stacked in contact with each other.

[0009]

According to the method of the present invention, the pressure applied at the time of lamination strongly acts on the portion where the internal electrodes are first stacked, but at the corresponding portion, the sheet with low hardness extends beyond the elastic limit. , The sheet is deformed and the portion where the internal electrodes are stacked becomes thin, and the reduced thickness moves to the portion where the internal electrodes are not stacked, that is, the portion where only the ceramic sheets are stacked, It acts to increase the thickness of the part and prevent the formation of voids there. In this way, a laminated body is obtained in which a substantially uniform pressure is applied to the portion where the internal electrodes are stacked and the portion where only the ceramic sheets are stacked to be pressure-bonded.

A detailed description will be given below with reference to embodiments.

[0011]

Example 1 A doctor blade prepared by mixing 100 parts by weight of a dielectric ceramic capacitor raw material powder, 40 parts by weight of an organic solvent, 0.2 parts by weight of a dispersant, 10 parts by weight of an organic binder, and 2.0 parts by weight of a plasticizer. A long sheet having a thickness of 20 μm was formed by the method, and the sheet was cut into a size of 85 mm × 110 mm square to prepare a plurality of ceramic green sheets. Two sheets of this green sheet are piled up, and at the temperature of 55 ℃, 108kg /
After pressure was applied by applying a pressure of cm ² , the edge of the sheet was gripped and the force for peeling at a constant speed was measured with a gauge. As a result, it was peeled with a force of 14 g.

Separately from this, 100 parts by weight of the dielectric ceramic capacitor raw material powder, 40 parts by weight of an organic solvent, 0.2 parts by weight of a dispersant, 10 parts by weight of an organic binder, and 5.0 parts by weight of a plasticizer are mixed as a slurry. Is formed into a long sheet with a thickness of 20 μm by the doctor blade method, and the sheet is 85 mm × 110 mm
A plurality of ceramic green sheets were prepared by cutting into a square size. Similar to the above, the peeling force is calculated to be 71g
Met.

On the sheet having a peeling force of 14 g, the pattern for the internal electrodes of the multilayer capacitor is formed by screen printing using a Pd conductive paste which is usually used, and on the sheet having a peeling force of 71 g, the electrode pattern is formed. I didn't. Next, in the mode shown in FIG. 1 (a), a sheet having a peeling force of 14 g (a ceramic green sheet having high hardness) having the internal electrodes 3 formed thereon and a sheet having a peeling force of 71 g having no internal electrodes formed thereon (Ceramic green sheets with low hardness) 2 layers are alternately laminated, 2 sheets with internal electrodes are not printed and 2 sheets with a peeling force of 14 g are laminated on the upper and lower sides, and pressed by a hydraulic laminator, as shown in FIG. 1 (b). A ceramic sheet laminated body 4 as shown in was constructed. The monolithic ceramic capacitor thus configured was cut, and the positional deviation of the width of the internal electrodes was measured. As a result, it was 22.3 μm.

[0014]

[Comparative Example] In Example 1, a plurality of green sheets each having an internal electrode 3 printed on a sheet (ceramic green sheet having high hardness) 1 having a peeling force of 14 g are stacked in the manner shown in FIG. As a result of performing the same operation as in Example 1 except that the ceramic sheet laminate 4 as shown in FIG. 3 (b) was formed, the positional deviation of the width of the internal electrode was 48.7 μm.

[0015]

[Embodiment 2] In Embodiment 1, a laminated body for a laminated ceramic capacitor is described, but the same effect can be obtained by applying the method of the present invention to a ceramic laminated body for producing a laminated inductor or the like. Further, in the above embodiment, the sheets having different hardness are formed separately,
Although the example in which the sheets are alternately stacked is shown, the effect of the present invention can be obtained by integrally forming sheets having different hardnesses and stacking the sheets as shown in FIG. That is,
A soft sheet (ceramic green sheet having low hardness) 2 is formed on a base film, and a hard sheet (ceramic green sheet having high hardness) 1 is formed on the base sheet to be integrated, and an internal electrode is formed on the surface of the hard sheet 1. Forming 3,
2 (b) is obtained by stacking a plurality of integrated green sheets 1, 2 and 3 in a mode as shown in FIG. 2 (a) and pressing them in the same manner as in Example 1. Such a ceramic sheet laminate 4 can be obtained. The positional deviation of the internal electrode width of this laminated body is improved as in the case of the first embodiment.

After a hard sheet is formed on the base film, one main surface of the sheet is sprayed with a plasticizer, an organic solvent or the like to soften the main surface, and the main surface is peeled to separate the main surface on the opposite side. One of the sheets by forming a hard green sheet by applying a ceramic slurry for a hard green sheet on a method of forming a conductor on the hard sheet surface of the surface or by applying a plasticizer or the like to the surface of the base film in advance. By the method of softening the main surface, a ceramic sheet in which 1, 2, and 3 are integrated, which is substantially the same as in the case of the second embodiment, is made, and the hard surface and the soft surface are contacted using this sheet. Also by stacking them, a laminate substantially the same as that shown in FIG. 2B can be formed. The electrode elongation of the laminate thus obtained is small as in the case of Example 2.

[0017]

EFFECTS OF THE INVENTION According to the present invention, the conductor formed inside the ceramic laminate is prevented from being stretched due to the imbalance of the applied pressure, the pattern accuracy of the inner conductor is improved, and the characteristics and the quality are improved. Can be measured.

[Brief description of drawings]

FIG. 1 (a) is an explanatory view showing a stacking mode of ceramic green sheets in Example 1 which is an example of the method of the present invention in a sectional view of the green sheets, and FIG. It is sectional drawing of the ceramic sheet laminated body produced by.

FIG. 2 (a) is an explanatory view showing a stacking mode of ceramic green sheets in Example 2, which is another example of the present invention, in a sectional view of the green sheets, and FIG. FIG. 3 is a cross-sectional view of a ceramic sheet laminated body produced by

FIG. 3 (a) is an explanatory view showing a mode of stacking ceramic green sheets in a conventional method with a cross-sectional view of a green sheet, and FIG. 3 (b) is a ceramic sheet laminate formed by press-bonding the above-mentioned sheet group. FIG.

[Explanation of symbols]

 1 Highly advanced ceramic green sheet 2 Low hardness ceramic green sheet 3 Internal electrodes 4 Ceramic sheet laminate

Claims (3)

[Claims] 1. A ceramic green sheet is coated with a conductive paste, and then the sheets are repeatedly stacked to stack a large number of sheets, which are pressure-bonded to form a laminated body, and the laminated body has a predetermined size. In the method for manufacturing a ceramic laminate, which comprises cutting into chip pieces and firing, preparing ceramic green sheets having different hardness as the ceramic green sheets, and applying the conductive paste onto the ceramic green sheet having the higher hardness. However, the method for producing a ceramic laminate is characterized in that the conductive paste is not applied onto the lower ceramic green sheet, and these hard and soft green sheets are alternately stacked and crimped. 2. A ceramic green sheet is coated with a conductive paste, and then the sheets are repeatedly stacked to stack a number of sheets, which are pressure-bonded to form a laminated body, and the laminated body has a predetermined size. In a method for manufacturing a ceramic laminate, which comprises shredding into chip pieces and firing, one main surface of each ceramic green sheet is a hard surface having high hardness, and the other main surface is a soft surface having low hardness. A method for manufacturing a ceramic laminate, characterized in that a conductive paste is applied only on the surface, and the green sheets are laminated so that the hard surface and the soft surface are in contact with each other and pressure-bonded. 3. A hard green sheet is formed by applying a ceramic slurry for a hard green sheet on a base film, and then a plasticizer or an organic solvent is sprayed on one main surface of the sheet, or A method of softening one main surface of a green sheet by forming a hard green sheet by applying a ceramic slurry for a hard green sheet on a surface to which a plasticizer or an organic solvent has been previously applied.