JP3239718B2 - Manufacturing method of multilayer ceramic electronic component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a multilayer ceramic electronic component such as a multilayer ceramic capacitor.

[0002]

2. Description of the Related Art Hitherto, a monolithic sintered type multilayer ceramic electronic component using Pd or an alloy containing Pd as a main component as an electrode metal layer has been fired in the air. However, firing in the air tends to cause internal structural defects due to oxidative expansion of the internal electrodes. In order to solve this problem, a method in which the binder is treated in an atmosphere in which Pd is not oxidized has been adopted in the binder removal treatment step. Was.

[0003]

However, when the binder is removed in an atmosphere in which Pd is not oxidized, the decomposition of the binder becomes insufficient and the amount of residual carbon increases.
As a result, there is no internal structural defect after sintering, but there is a problem that the performance is degraded in electrical characteristics.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a multilayer ceramic electronic component such as a multilayer ceramic capacitor which suppresses internal structural defects and has high reliability.

[0005]

Means for Solving the Problems The method of the present invention in order to achieve this object, in the course of Atsushi Nobori debinding step was treated in an atmosphere in which the electrode metal layer is not oxidized, the electrode metal in the subsequent cooling process The layer is not oxidized in the atmosphere
After the temperature has dropped to a
Maintain and process to achieve the initial objectives.

[0006]

In the treatment method according to the first aspect of the present invention, the electrode metal layer is treated in an atmosphere in which the electrode metal layer is not oxidized in the temperature rising step of the debinding step, and the electrode metal layer is treated in the atmosphere in the subsequent temperature lowering step. Temperature to a temperature range where it is not oxidized
After that, the binder is burned appropriately by maintaining and processing at that temperature in the atmosphere for a predetermined time . Therefore, it is possible to prevent the electrode metal layer from being oxidized before firing and sufficiently reduce the amount of carbon remaining. As a result, the temperature range in which the electrode metal layer is oxidized in the air during the firing process is to be fired in an inert atmosphere. In such a case, the sintered body has a small amount of residual carbon, so that a decrease in insulation can be suppressed, and the occurrence of internal defects can be prevented.

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described.
Will be described. First, a ceramic green sheet having a thickness of 13 μm made of a dielectric powder containing barium titanate as a main component and an organic binder was prepared, and an electrode paste using Pd powder having an average particle diameter of 0.4 μm as a metal component was applied to the green sheet at a thickness of 3 μm. Printing was carried out with a thickness, whereby ceramic layers and electrode metal layers were alternately laminated to produce a green chip comprising 50 effective layers. In this green chip, an anti-fusing material is adhered to the surface by static electricity, and the surface is coated with zirconia-coated alumina-based sheath to a height of 10 mm. Binder treatment was performed. After the binder removal treatment, the mixture was calcined in nitrogen up to 900 ° C. and further up to 1320 ° C. in the air for the temperature lowering process. The heating rate in this firing step was 200 ° C./hr.

(Binder removal treatment conditions) (1) As shown in FIG.
Hold at 50 ° C. for 2 hours.

(2) As shown in FIG. 1, the temperature is raised from room temperature to the maximum temperature of 450 ° C. in the temperature raising process, held for 2 hours at the maximum temperature of 450 ° C., and the temperature is reduced from 450 ° C. to 300 ° C. in nitrogen in 300 ° C. Keep at ℃ for 2 hours in air and cool down in air.

In each of the binder removal experiments, the heating rate was 100 ° C./hr.

The amount of residual carbon in the chip after the removal of the binder, the rate of occurrence of internal structural defects after firing, and the insulation resistance after applying an external electrode to the sintered body were measured. The amount of residual carbon was measured by an infrared absorption method, and 30 samples were used for the evaluation of internal structural defects and insulation resistance, respectively. The results are shown in (Table 1).

[0012]

[Table 1]

As is clear from Table 1, conditions 1 and 2
In both cases, although no internal structural defect occurs, a decrease in insulation resistance is observed under condition 1, whereas a favorable insulation resistance result is shown under condition 2. This result also indicates that the binder removal is insufficient when the binder removal treatment is performed only in nitrogen.

(Embodiment 2) Using the same green chips as used in Embodiment 1, in the binder removal process, the temperature is raised from room temperature to a maximum temperature of 450 ° C. during the temperature rise process, The temperature is maintained for 2 hours at a temperature of (1) 200 ° C. (2) 250
C. (3) 280.degree. C. (4) 320.degree. C. (5) 330.degree. C., and then debinding treatment was performed in air. Also in this experiment, the heating rate was 100 ° C./hr. Thereafter, chip baking conditions were the same as in the first embodiment. And the amount of residual carbon,
The internal structural defect occurrence rate and insulation resistance were evaluated. The results are shown in (Table 2).

[0015]

[Table 2]

As can be seen from Table 2, the incidence of internal structural defects was 0 in all of the conditions 1 to 4. Further, under the conditions 1 and 2, the insulation resistance is deteriorated. Further, under the conditions 3 and 4, the insulation resistance did not deteriorate. Under condition 5, an internal structural defect occurred. From these results, in order to obtain a product with no internal structural defects and good insulation resistance,
Residual carbon amount after debinding is 0.4 to 0.76w
It is understood that the range of t% is suitable, and that the temperature of 320 ° C. or lower is suitable for opening to the atmosphere.

(Embodiment 3) Using the same green chips as used in Embodiment 1, a binder removal treatment was performed at the following heating rate.

(1) The temperature raising rate is 50 ° C./hr, and both the temperature raising and the temperature lowering are in nitrogen. (2) The temperature raising rate is 25 ° C./hr, and both the temperature raising and the temperature lowering are in nitrogen. Processing was performed under the same conditions as in 1. The results of evaluating the residual carbon content, the internal structural defect occurrence rate, and the insulation resistance in the same manner as in Embodiment 1 are shown in Table 3.

[0019]

[Table 3]

As can be seen from Table 3, no internal defect occurred in any of the conditions 1 and 2, but the method of the condition 1 deteriorated the insulation resistance and the method of the condition 2 deteriorated the insulation resistance. Is slightly improved but not enough. From this result, it can be seen that in the case of performing the binder removal treatment, the binder removal treatment is insufficient only by slowing down the heating rate and taking time.

As described above, a monolithically sintered type multilayer ceramic electronic component comprising an electrode metal layer and a ceramic layer contains a large amount of various organic binders. In order to obtain the effect of removing the binder, it is difficult to efficiently and sufficiently burn off by removing the binder only in an inert atmosphere. In order to solve this, in the debinding treatment step in the above embodiment of the present invention, from room temperature to the maximum temperature at the time of temperature rise, from the maximum temperature at the time of temperature decrease to 320 ° C. in an inert atmosphere, and below that in the atmosphere. Is to be processed. As a result, even in the case of industrial large-scale processing, the occurrence of internal structural defects can be suppressed, and the insulating property can be prevented from lowering, so that an excellent ceramic electronic component can be provided. It is also considered possible to remove the binder for a long time in an inert atmosphere in the binder removal treatment step, but this is not preferable in terms of economy. Further, although Pd is used as the electrode metal in the present embodiment, it goes without saying that the same effect can be obtained when a metal such as Ni is used instead of Pd.

[0022]

As described above, the production method according to the present invention provides:
Although the ceramic layer and the electrode metal layer are alternately laminated,
During heating during the debinding treatment electrode metal layer is treated in an atmosphere not oxidized, the in the subsequent cooling process
Temperature dropped to a temperature range where the electrode metal layer was not oxidized in the atmosphere
After that, by maintaining and treating at the same temperature for a predetermined time in the atmosphere, it is possible to suppress the occurrence of internal structural defects and to provide a multilayer ceramic electronic component having good characteristics without a decrease in insulation resistance. Is possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing processing conditions during binder removal processing according to Embodiment 1 of the present invention.

FIG. 2 is a view showing processing conditions at the time of a conventional binder removal processing.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-299289 (JP, A) JP-A-6-349673 (JP, A) JP-A-5-335177 (JP, A) JP-A-5-335177 90066 (JP, A) JP-A-63-15408 (JP, A) JP-A-7-106187 (JP, A) JP-A-6-151237 (JP, A) JP-A-1-230214 (JP, A) JP-A-6-168841 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 4/00-4/12 H01G 4/14-4/42 H01G 13/00-13 / 06

Claims (1)

(57) [Claims] In a binder removing process for a multilayer ceramic electronic component in which a plurality of ceramic layers and electrode metal layers are alternately stacked, a temperature rise process is performed in an atmosphere in which the electrode metal layer is not oxidized, and then a temperature decrease is performed. In the process, after the temperature of the electrode metal layer is lowered to a temperature range in which the electrode metal layer is not oxidized in the air, the electrode metal layer is maintained at the temperature for a predetermined time in the air and processed .