JP3089927B2 - How to clean electronic components - 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 cleaning an electronic component, and more particularly to a method for cleaning an electronic component having an external electrode formed by applying and baking a conductive paste.

[0002]

2. Description of the Related Art External electrodes of electronic components such as chip-type multilayer ceramic capacitors and chip-type LC composite components are usually formed by applying and baking a conductive paste such as a silver paste.

[0003] In the past, electronic parts having external electrodes formed thereon have been cleaned using a Freon-based cleaning agent or the like.

[0004]

The freon-based cleaning agent used in the cleaning step has problems such as destruction of the ozone layer, and therefore its use is expected to be prohibited. The need is growing.

[0005] Even when the powder is washed with the above-mentioned freon-based detergent, the powder used at the time of baking may adhere to the external electrode and remain after the cleaning. There are problems such as poor contact of the terminals, which hinders sorting, and poor soldering.

In addition, the above electronic component has a problem that a good external electrode having excellent surface smoothness cannot be obtained due to irregularities generated on the surface of the external electrode during baking or the like.

Further, in the above electronic component, after a conductive paste such as a silver paste is applied and baked to form a baked electrode (external electrode) such as a silver electrode, solder cracking is prevented and solderability is improved. For the purpose, Ni plating or Cu plating may be applied on a baked electrode such as a silver electrode, and Sn plating may be applied thereon.
For example, in a Sn plating process, there is a problem that a plating solution intrudes into the inside from the electrode surface to cause deterioration of electric characteristics.

The present invention has been made to solve the above problems, and it is possible to reliably clean an electronic component after forming an external electrode without using a cleaning agent such as a freon-based cleaning agent that causes environmental destruction. An object of the present invention is to provide a method for cleaning an electronic component, which is possible and can flatten unevenness generated on the surface of an external electrode during baking of a conductive paste or the like.

[0009]

In order to achieve the above object, a method for cleaning an electronic component according to the present invention (claim 1) is to clean an electronic component on which external electrodes are formed by applying and baking a conductive paste. The electronic component on which the external electrodes have been baked is made of an inorganic powder having a particle size of 1 mm or less.
And 0.5-10% by volume, and wherein the stirring was charged into a container with washing medium containing water 90 to 99.5 volume%.

Further, the method for cleaning an electronic component according to claim 2 is
The average particle size of the inorganic powder is 0.1 mm or less.
Sign.

[0013] In a third aspect of the present invention, there is provided a method for cleaning electronic parts.
The ratio of the electronic component to the cleaning medium (electronic component: cleaning medium)
Body) in a volume ratio of 1:20 to 1: 1.
Features.

Further, the method for cleaning an electronic component according to claim 4 is as follows.
The inorganic powder is made of alumina, zirconia, or silica.
At least one member selected from the group consisting of
You.

[0013]

The electronic component on which the external electrodes have been baked is put into a container together with a cleaning medium containing an inorganic powder having a particle size of 1 mm or less and water and stirred, whereby the electronic component constitutes the cleaning medium. Efficient contact with inorganic powder ensures that powder and dirt adhering to external electrodes and element surfaces are reliably removed, and that irregularities on the surface of external electrodes during baking etc. By contacting the component, the surface becomes flat, and the surface of the external electrode is smoothed.

As the inorganic powder constituting the cleaning medium used in the present invention, the powder or dirt attached to the external electrode or element surface is removed by contacting the external electrode or element surface of the electronic component. Alternatively, it is possible to use various inorganic powders that can make the unevenness flat by contacting the unevenness on the surface. In addition, examples of preferable inorganic powders include inorganic oxides such as alumina, zirconia, and silica, but are not limited thereto.

[0015] The particle diameter of the inorganic powder constituting the cleaning medium is preferably 1 mm or less. It has a particle size of 1mm
When the value exceeds, the dimensions become too large in relation to the electronic component to be cleaned, making it difficult to make uniform and efficient contact with the electronic component, and the cleaning efficiency is reduced. In particular, the particle size of the inorganic powder is preferably 0.1 mm or less. If the particle size is 0.1 mm or less, the contact state between the inorganic powder and the electronic component in the cleaning step becomes more uniform, and a better cleaning effect can be obtained.

Since the preferable particle size of the inorganic powder is also related to the size and shape of the electronic component, it is preferable to appropriately determine the size in consideration of the size and shape of the electronic component to be cleaned.

In the method of cleaning an electronic component according to the present invention, there is no particular restriction on the content of the inorganic powder and water in the cleaning medium.
It is preferable that the content of water is in the range of 90 to 99.5% by volume.

In the method of cleaning an electronic component according to the present invention, the ratio of the electronic component to the cleaning medium in the cleaning step is not particularly limited, but usually, the ratio of the electronic component to the cleaning medium is 1: 1: It is preferred to be in the range of 20 to 1: 1.

Further, in the method of cleaning an electronic component according to the present invention, there is no particular limitation on a method of stirring the electronic component together with the cleaning medium, and a method of stirring using a stirrer and a method of vibrating (oscillating) the container. Alternatively, it is possible to use various methods such as a method of rotating a rotating container such as a rotating barrel as a container, but in order to stably and uniformly agitate the rotating container such as a rotating barrel. It is preferred to use and stir.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a method for cleaning an electronic component according to one embodiment of the present invention, and FIG. 2 is a view showing a rotary barrel used in this embodiment.

In this embodiment, a multilayer ceramic capacitor (electronic component) 1 having an external electrode formed by applying and baking a conductive paste (for example, a silver paste) is mixed with an inorganic powder having an average particle diameter of 0.1 mm or less (such as an inorganic powder). In the embodiment, a hexagonal cylindrical rotary barrel 3 is used together with a cleaning medium 2 containing 1.0% by volume of zirconia powder) and 99% by volume of water.
(FIG. 2), the rotating barrel 3 was rotated at a rotation speed of 90 times / minute at normal temperature, and washing was performed for 0.2 hours.

In this embodiment, the multilayer ceramic capacitor 1 and the cleaning medium 2 were charged into the rotating barrel 3 at a ratio of 1:10 by volume.

After completion of washing, a measuring terminal is connected to the external electrode of the obtained multilayer ceramic capacitor, and electric characteristics such as capacitance, insulation resistance, and quality of contact are checked.
The solderability was examined. Table 1 shows the results.

[0024]

[Table 1]

For comparison, the same measurement was performed for an electronic component (multilayer ceramic capacitor) cleaned using a conventional Freon-based cleaning agent. The results are shown in Table 1.

From Table 1, it can be seen that the multilayer ceramic capacitor cleaned with the conventional Freon cleaning agent has a capacity failure of 0.14%, insulation resistance failure of 2.18%, and contact failure of 1%.
In contrast to the occurrence at a rate of 1.27%, the multilayer ceramic capacitor cleaned by the method of the embodiment has a capacity failure of 0.02%, insulation resistance failure of 0.91%, and contact failure of 0.29%. It can be seen that in the multilayer ceramic capacitor cleaned by the method of the embodiment, the failure occurrence rate is significantly reduced in all items such as capacitance, insulation resistance, and quality of contact.

Regarding the solderability, the defect rate was 1.0% in the conventional cleaning method, whereas no defect was recognized in the cleaning method of the embodiment.

In the above-described embodiment, the case of a so-called non-plated product in which the external electrode is not subjected to Ni plating or Sn plating after cleaning is described. However, a so-called plated product in which Ni plating or Sn plating is applied after cleaning. It has been confirmed that the same effect as in the above embodiment can be obtained also in the case of (1).

In the case of an electronic component (plated product) that has been cleaned with a conventional Freon-based cleaning agent, a plating solution enters the element through an external electrode in the Sn plating step,
In some cases, the electrical characteristics were deteriorated, but almost no penetration of the plating solution into the inside of the element was observed in the electronic component cleaned by the cleaning method of the present invention.

Further, in the above-described embodiment, a multilayer ceramic capacitor has been described as an example. However, there are no particular restrictions on the types of electronic components to which the present invention can be applied. Positive thermistor devices, semiconductor components, piezoelectric components The present invention can be applied to various electronic components having external electrodes, such as LC composite components.

The present invention is not limited to the above-described embodiment, but includes the specific shape of the electronic component, the shape and constituent material of the external electrode, and the specific shape of the external electrode by applying and baking a conductive paste. With respect to the forming method, the cleaning temperature, the cleaning time, and the shape and the rotation speed of the rotary barrel when the rotary barrel is used, various applications and modifications can be made within the scope of the invention.

[0032]

As described above, the method for cleaning an electronic component according to the present invention is characterized in that the electronic component having the external electrode baked is treated with 0.5 to 10% by volume of an inorganic powder having a particle size of 1 mm or less, ~
Since it is put into a container together with a cleaning medium containing 99.5% by volume and agitated, without using a cleaning agent such as a freon-based cleaning agent that causes environmental destruction,
The electronic component after the formation of the external electrode can be reliably cleaned.

Therefore, according to the method of cleaning an electronic component of the present invention, it is possible to reduce the rate of occurrence of contact failure in the electrical property selection step and to improve the solderability.

Further, according to the method for cleaning an electronic component of the present invention, it is possible to flatten the unevenness of the surface of the external electrode generated at the time of baking or the like, and to provide a good external electrode having excellent surface smoothness. An electronic component having the same can be obtained.

Further, when Sn plating is performed on the external electrode, it is possible to prevent Sn from entering the inside from the uneven electrode surface, thereby preventing deterioration of the electric characteristics.

Further, the method for cleaning an electronic component according to the second aspect is provided.
As described above, inorganic powders having an average particle size of 0.1 mm or less
And cleaning of the electronic component according to claim 3.
As in the method, the ratio of the electronic component to the cleaning medium is
1:20 to 1: 1 range, or
An inorganic powder is used as in the method for cleaning an electronic component according to claim 4.
Selected from the group consisting of alumina, zirconia, and silica
External electrode formation by using at least one of
After-parts can be more reliably cleaned
become.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the present invention, and is a cross-sectional view showing a state where an electronic component is put into a rotary barrel together with a cleaning medium.

FIG. 2 is a perspective view showing a rotary barrel used in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component 2 Cleaning medium 3 Rotating barrel

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kazuhide Moriyoshi 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Inventor Kenichi Ito 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto In Murata Manufacturing Co., Ltd. (56) References JP-A-60-143620 (JP, A) JP-A-5-309556 (JP, A) JP-A-6-112085 (JP, A) JP-A-7-22271 (JP, A) JP 62-37525 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B24B 31/14 B08B 3/10 B24B 31/00

Claims (4)

(57) [Claims] 1. A coating a conductive paste, a method of cleaning electronic components forming the external electrodes by baking, an electronic component baking of the external electrodes is performed, the inorganic powder 0.5 particle size 1mm or less 10% by volume and, water 90 to 99.5 volumes
A method for cleaning an electronic component, comprising charging a container together with a cleaning medium containing an amount of 0.1% and stirring the mixture. 2. An inorganic powder having an average particle size of 0.1 mm or less.
2. The method for cleaning electronic parts according to claim 1, wherein
Law. 3. The ratio of the electronic component to the cleaning medium (electronic
Parts: cleaning medium) in a volume ratio of 1:20 to 1: 1
The electronic component according to claim 1, wherein
Cleaning method. 4. The method according to claim 1, wherein the inorganic powder is alumina, zirconia,
At least one selected from the group consisting of silica
The electronic part according to any one of claims 1 to 3, wherein
How to wash items.