JP2001044065A - Manufacture of laminated ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manufacturing method of a laminated ceramic electronic component which hardly generates shortcircuit defects between inner electrodes and is superior in reliability, even if a ceramic layer between inner electrodes is made thin. SOLUTION: In this manufacturing method of a laminated ceramic electronic component, a ceramic green sheet 2 is formed by applying ceramic slurry to one side of a PET film 1 as a synthetic resin film base, having a surface whose maximum height RMAX defined in JIS B0601 is at most 1.5 μm and drying it, and thereafter printing of an inner electrode pattern, lamination of a ceramic green sheet, baking of a laminate and formation method of an external electrode are carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a multilayer ceramic electronic component such as a multilayer capacitor, and more particularly to a method of manufacturing a multilayer ceramic electronic component having a thin ceramic layer between internal electrodes.

[0002]

2. Description of the Related Art In recent years, in a multilayer capacitor, the thickness of a ceramic layer between internal electrodes has been reduced with the progress of miniaturization and large capacity. Therefore, when manufacturing a multilayer capacitor, a thinner ceramic green sheet is used.

However, a thin ceramic green sheet having a thickness of about 10 μm or less cannot be handled by itself. Therefore, when manufacturing a multilayer capacitor, first, a ceramic slurry is applied on a synthetic resin film substrate, and dried to form a ceramic green sheet. Thereafter, an internal electrode pattern is formed on the upper surface of the ceramic green sheet supported by the synthetic resin film substrate. Next, a plurality of ceramic green sheets on which the internal electrode patterns are printed are laminated while the synthetic resin film substrate is peeled off. In this way, a plurality of ceramic green sheets are laminated to obtain a mother laminate. After cutting the mother laminate into individual laminate capacitor units, the ceramic laminate is fired to obtain a ceramic sintered body. Thereafter, an external electrode is formed on the outer surface of the ceramic sintered body.

As the above synthetic resin film substrate, for example, a polyethylene terephthalate film or the like is used.

[0005]

As described above, the thickness of ceramic green sheets has become extremely thin with the miniaturization and large capacity of multilayer capacitors. On the other hand, a synthetic resin film substrate for obtaining the above-mentioned ceramic green sheet usually has irregularities on the surface. Therefore, when the unevenness is large, as shown in the sectional view of FIG. 7, the unevenness of the upper surface 51a of the synthetic resin film substrate 51 causes local dents in the ceramic green sheet 52, There was a problem that occurs. That is, since the thickness of the ceramic green sheet 52 is extremely small, the ceramic green sheet 52 is easily affected by irregularities on the surface of the synthetic resin film substrate 51, and the above-described dents and pinholes tend to occur. For this reason, in the finally obtained multilayer capacitor, internal electrodes are short-circuited, and the reliability of the multilayer capacitor tends to decrease.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art, and to provide a highly reliable laminate which is less likely to cause a short circuit between internal electrodes even when a thin ceramic green sheet is used. An object of the present invention is to provide a method for manufacturing a ceramic electronic component.

[0007]

According to the present invention, there is provided a method of manufacturing a multilayer ceramic electronic component, comprising the steps of: forming a single-sided synthetic resin film substrate having a surface having a maximum height R _Max defined by JIS B0601 of 1.5 μm or less; Applying a ceramic slurry and drying to form a ceramic green sheet on a synthetic resin film substrate, printing an internal electrode pattern on the ceramic green sheet, and printing the internal electrode pattern. Stacking at least a plurality of ceramic green sheets to obtain a laminate, firing the laminate to obtain a ceramic sintered body, and forming an external electrode on the outer surface of the ceramic sintered body. And characterized in that:

Preferably, when the thickness of the ceramic green sheet is t, the ceramic slurry is applied such that the maximum height R _MAX / t is 0.4 or less.

More preferably, the ceramic green sheet has a thickness of 10 μm or less, more preferably 7 μm or less. Hereinafter, details of the present invention will be described.

In the present invention, a synthetic resin film substrate having a surface having a maximum height R _MAX defined by JIS B0601 of 1.5 μm or less is used. That is, the roughness of the surface, R _MAX is the following smooth synthetic resin film substrate 1.5μm used. Note that the maximum height R _MAX is shown in FIG.
As shown in the figure, the height between the deepest part and the highest part in the uneven surface is referred to.

When R _MAX exceeds 1.5 μm, the surface becomes too rough, and when a ceramic green sheet is formed, dents and pinholes in the ceramic green sheet are likely to occur.

The synthetic resin constituting the synthetic resin film substrate is not particularly limited, but for example, polyethylene terephthalate, polypropylene and the like can be suitably used.

In the present invention, a ceramic green sheet is formed by applying a ceramic slurry to one surface of a synthetic resin film substrate having a smooth surface as described above and drying the slurry. As the ceramic slurry, a ceramic slurry mainly composed of an appropriate ceramic powder such as a dielectric ceramic powder, a magnetic ceramic powder, a semiconductor ceramic powder, or a piezoelectric ceramic powder can be used. That is, the present invention can be applied not only to a multilayer capacitor but also to the manufacture of a multilayer varistor, a multilayer thermistor, or a multilayer piezoelectric resonance component, and a ceramic slurry suitable for these applications is used.

The thickness of the ceramic green sheet is not particularly limited. However, when the thickness of the ceramic green sheet is small, dents and pinholes are likely to occur. If more effective. Preferably, 10μ
m or less, and more preferably 7 μm or less in thickness, so that the thickness of the ceramic layer between the internal electrodes can be made smaller. Can be suppressed.

[0015] Preferably, the thickness of the ceramic green sheet when the t, ceramic slurry as R _{MA X} / t is 0.4 or less is applied, thereby apparent from the experimental examples described later As described above, short-circuit failure and the like can be effectively prevented.

The method of applying the ceramic slurry is not particularly limited, and an appropriate method such as a doctor blade method can be used. Further, in the present invention, the steps after forming the ceramic green sheets on the synthetic resin film substrate as described above can be performed in accordance with a conventionally known method for manufacturing a laminated ceramic electronic component.

That is, in printing the internal electrode pattern on the ceramic green sheet, an appropriate method such as screen printing of a conductive paste can be used. In addition, the step of laminating at least a plurality of ceramic green sheets on which the internal electrode patterns are printed to obtain a laminated body may be performed according to the number of laminated internal electrodes of the intended laminated ceramic electronic component. Further, not only a plurality of ceramic green sheets on which the internal electrode patterns are printed, but also an appropriate number of plain ceramic green sheets may be laminated on the upper and lower sides.

The step of firing the laminate to obtain a ceramic sintered body is performed under appropriate firing conditions depending on the ceramic used. The step of forming an external electrode on the outer surface of the ceramic sintered body can be performed by an appropriate method such as application and baking of a conductive paste, vapor deposition, plating, or sputtering. Further, external electrodes may be formed by further forming one or more plating films on the surface of the electrode film formed by applying and baking a conductive paste.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be clarified by giving specific examples of the present invention. (Example 1) As a synthetic resin film substrate, the following Table 1 was used.
As shown in, the maximum height R _MAX defined in JIS B0601 is 0.5 μm, 1.0 μm, 1.5 μm, 2.
Polyethylene terephthalate (PET) films of Sample Nos. 1 to 5 having 0 μm and 3.0 μm were prepared.

A ceramic slurry mainly composed of barium titanate-based ceramic powder is applied to one surface of each of the above PET films so that the thickness of the obtained ceramic green sheet is 4.0 μm on average, dried, and dried. A sheet was formed. FIG. 1 shows that R _MAX = 0.5
This shows a state in which a ceramic green sheet 2 is laminated on a PET film 1 of μm. The values of R _MAX / t when the PET films of the sample numbers 1 to 5 are used are shown in Table 1 below.

Next, as shown in FIG.
The Ni paste was screen-printed on the ceramic green sheet 2 obtained by using each of the above PET films to form the internal electrode patterns 3. Each ceramic green sheet on which the internal electrode pattern was printed as described above was punched into a rectangular shape, and was conveyed to a lamination station. In the laminating station, laminating 100 ceramic green sheets while peeling off the PET film, and further laminating plain ceramic green sheets up and down,
The mother laminate was obtained by pressing in the thickness direction.

Next, the mother laminate was cut into individual multilayer capacitor units. In the multilayer body of each multilayer capacitor obtained as described above, the internal electrodes 4 and 5 shown in FIG. 4 are alternately stacked. Next, the laminate was fired to obtain a ceramic sintered body shown in FIG.

In the ceramic sintered body 11, as shown schematically, the internal electrodes 12 to 17 are arranged so as to overlap each other via the ceramic layer. Actually, as described above, 100 internal electrodes are stacked. The size of the obtained ceramic sintered body 11 is 3.2 m.
m × 1.6 mm × thickness 1.6 mm.

Thereafter, a conductive paste is applied so as to cover the end faces 11a and 11b of the ceramic sintered body 11,
Baking was performed to form an electrode film. Further, a Ni plating film and a Sn plating film are sequentially formed on this electrode film, and FIG.
As shown in FIG. 7, external electrodes 18 and 19 were formed. In addition,
In FIG. 6, the external electrodes 18 and 19 are shown as a single layer.

With respect to the multilayer capacitor 20 obtained as described above, the short-circuit failure rate was determined in the following manner. Evaluation of short-circuit defect rate: The number of short-circuit defects in the sample was measured with the sample N = 1000. Using a C meter, sorting was performed at 1 kHz and 1V. The results are shown in Table 1 below.

[0026]

[Table 1]

Note that R _MAX in Table 1 is a value measured using a contact type surface roughness meter, but it is also possible to use a surface roughness meter using a laser beam instead of the contact type surface roughness meter. Good. As is clear from Table 1, when R _MAX indicating the surface roughness of the PET film is 0.5 to 1.5 μm, or when R _MAX / the thickness of the ceramic green sheet is 0.4 or less, short-circuit failure occurs. While not occurring, PET
It can be seen that the greater the irregularities on the film surface, the higher the short-circuit failure occurrence rate.

Therefore, according to the present invention, a synthetic resin film substrate having a surface roughness R _MAX of 1.5 μm or less is used as the surface roughness of the synthetic resin film substrate.
_It can be seen that by applying the ceramic slurry so that _MAX / t is 0.4 or less, short circuit failure can be reliably prevented.

(Example 2) Sample No. 1 used in Example 1
5 to 7, except that the thickness of the ceramic green sheet was 3 μm, 5 μm, 7 μm, 10 μm, and 15 μm, and the others were the same as in Example 1 to obtain multilayer capacitors. The short circuit failure rate was evaluated. The results are shown in Table 2 below.

[0030]

[Table 2]

As is evident from Table 2, even when the thickness of the ceramic green sheet is varied between 3 and 15 μm, the surface roughness of the PET film is not changed when R _MAX is 1.5 μm or less, or when R _MAX is 1.5 μm or less. _It can be seen that short circuit failure can be effectively prevented by forming the ceramic green sheet so that _MAX / t is 0.4 or less.

In Examples 1 and 2, a ceramic green sheet was formed on a PET film, an internal electrode pattern was printed, punched into a rectangular shape, and the ceramic green sheet supported by the PET film was sucked by a suction chuck. Holding, transporting, P
Although a laminate was obtained by repeating the process of laminating the ceramic green sheets peeled from the ET film, the ceramic green sheets were pressed and crimped onto the ceramic green sheets already laminated together with the synthetic resin film base material. Thereafter, a pressure lamination method in which the step of peeling the synthetic resin film substrate is repeated may be used.

[0033]

As described above, in the method for manufacturing a multilayer ceramic electronic component according to the present invention, the maximum height R _MAX is 1.5.
Using a synthetic resin film substrate having a surface of μm or less,
A ceramic green sheet is formed by applying a ceramic slurry to one surface of the synthetic resin film substrate and drying it. Therefore, even when the thickness of the ceramic green sheet is small, dents and pinholes are less likely to occur in the ceramic green sheet because the surface of the synthetic resin film substrate is smooth. Therefore, in the finally obtained multilayer ceramic electronic component, a short circuit failure between the internal electrodes hardly occurs, and a multilayer ceramic electronic component having excellent reliability can be provided.

Further, in the present invention, R _MAX / t is set to 0.
When the ceramic slurry is applied so as to be 4 or less, it is possible to provide a highly reliable multilayer ceramic electronic component in which short-circuit failure is unlikely to occur, as is clear from the above-described embodiment.

Further, when the thickness of the ceramic green sheet is 10 μm or less, more preferably 7 μm or less, the thickness of the ceramic green sheet becomes extremely small. Thus, for example, a small-sized and large-capacity multilayer capacitor can be easily provided. Even in such a case, short-circuit failure is unlikely to occur, so that a highly reliable multilayer ceramic electronic component can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing a state in which a ceramic green sheet is formed on a PET film as a synthetic resin film substrate in one embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining R _MAX .

FIG. 3 is a perspective view showing a state in which an internal electrode pattern is printed on a mother ceramic green sheet.

FIG. 4 is a schematic perspective view for explaining the internal electrode lamination state in the multilayer capacitor.

FIG. 5 is a sectional view showing a ceramic sintered body obtained in an example.

FIG. 6 is a longitudinal sectional view showing the multilayer capacitor obtained in the example.

FIG. 7 is a partially cutaway sectional view showing a state in which a ceramic green sheet is formed on a synthetic resin film substrate in a conventional method for manufacturing a multilayer ceramic electronic component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... PET film as a synthetic resin film base material 2 ... Ceramic green sheet 3 ... Internal electrode pattern 4,5 ... Internal electrode 11 ... Ceramic sintered body 12-17 ... Internal electrode 18, 19 ... External electrode 20 ... Multilayer capacitor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takao Hosokawa 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (Reference) 5E001 AB03 AC04 AC09 AD00 AE02 AE03 AF00 AF06 AH01 AH05 AH06 AH09 AJ01 AJ02

Claims (4)

[Claims] A ceramic slurry is applied to one surface of a synthetic resin film substrate having a surface having a maximum height R _Max of 1.5 μm or less as defined in JIS B0601, and dried to obtain a synthetic resin film substrate. Forming a ceramic green sheet thereon; printing an internal electrode pattern on the ceramic green sheet; and laminating at least a plurality of ceramic green sheets on which the internal electrode pattern is printed to obtain a laminate. And baking the laminate to obtain a ceramic sintered body; and forming an external electrode on the outer surface of the ceramic sintered body. 2. The ceramic slurry is applied such that the maximum height R _MAX / t is 0.4 or less, where t is the thickness of the ceramic green sheet. 2. The method for manufacturing a multilayer ceramic electronic component according to item 1. 3. The method according to claim 1, wherein the thickness of the ceramic green sheet is 10 μm or less. 4. The method according to claim 3, wherein the thickness of the ceramic green sheet is 7 μm or less.