JPH0685437A - Cleaning method of electronic part - Google Patents

Abstract

PURPOSE:To facilitate the transfer to an alternative cleaning method without deteriorating the quality of the electronic part by a method wherein the electronic part is immersed in a cleaning solution to be cleaned up at reduced or increased pressure. CONSTITUTION:When the air pressure in an airtight vessel 1 is reduced through a hole in a vessel part 2, the bubbles 9 in a gap part 8 formed between a substrate 6 and a part 7 are made easier to rise up for venting the gap part 8 thereby making a cleaning solution 4 easier to creep in the gap part 8. On the contrary, when the air pressure in the airtight vessel 1 is increased, the volume of the bubbles 9 in the gap part 8 is decreased thereby making the cleaning solution 4 easier to creep in the gap part 8 by the decreased volume. Accordingly, any flux adhering to the gap part 8 under the reduced or increased pressure can be removed easier. Furthermore, the creeping of the cleaning solution in the gap part 8 can be made easier thereby enabling the cleaning performance of the electronic part to be enhanced.

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 electronic parts, and more particularly to a method for cleaning electronic parts that does not use ozone depleting substances such as CFCs and ethane.

[0002]

2. Description of the Related Art In recent years, the destruction of the ozone layer by chlorine-based organic solvents such as CFCs and ethane has become a problem, and the total abolition thereof is urgently required. For example, the chlorine-based organic solvent is used in the cleaning process of electronic parts such as hybrid ICs, and the development of a so-called alternative cleaning method for cleaning without using the chlorine-based organic solvent is urgently needed. .

Currently proposed alternative cleaning methods are described below. Washing with water This is to remove the water-soluble flux with water. Alkali saponification This is a process in which a rosin (pine resin) -based flux is once dissolved in water by an alkali saponifying agent and then rinsed with water. Semi-aqueous cleaning This is a rosin-based flux for hydrocarbons, terpenes,
It is dissolved in a solvent such as higher alcohol or surfactant to remove it, and then rinsed with water. As described above, the conventional alternative cleaning method is mostly performed using water.

[0004]

However, for example, when cleaning the flux that has entered the gap between the substrate of an electronic component such as a hybrid IC and the component on the substrate, the conventional alternative cleaning method described above is used. There is a risk that the flux cannot be cleaned sufficiently and quality problems such as deterioration of the insulation of electronic parts may occur. The reason for this is that it is difficult for the solvent and water used in the conventional alternative cleaning method to enter the gap. There is a Nure index as a physical property value that indicates whether or not it easily enters a gap. This Nure index is, as expressed by equation (1),

Nudity index = (density × 1000) / (viscosity × surface tension)
(1)

This is a combination of density, viscosity and surface tension. If the value is large, it easily enters the gap. Therefore, by comparing the values, the cleanability of the gap can be compared. That is, Freon R-113 which is a chlorine-based organic solvent
Is 120, 1, 1, 1-trichloroethane, while the solvent and water used in the conventional alternative cleaning method are hydrocarbons and terpenes 30 to 40, higher alcohols and surfactants 5 to 20. , Water is 15, and the wetting index of the solvent or water used in the conventional alternative cleaning method is smaller than that of the chlorine-based organic solvent. Therefore, the solvent and water used in the conventional alternative cleaning method are inferior to the chlorine-based organic solvent in the cleaning property of the gap portion and the quality of the electronic component is deteriorated.

An object of the present invention is to provide a method for cleaning electronic parts which can facilitate the transition to the alternative cleaning method without degrading the quality of the electronic parts.

[0008]

In order to achieve the above-mentioned object, a method of cleaning an electronic component according to the present invention comprises immersing the electronic component in a cleaning liquid and cleaning the electronic component under reduced pressure or pressure. Characterize.

[0009]

According to the method of cleaning an electronic component of the present invention, as described above, by cleaning the electronic component under reduced pressure or pressure, it becomes easy for the cleaning liquid to enter the gap of the electronic component. The washability of parts can be improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram for explaining a method of cleaning an electronic component according to an embodiment of the present invention. In this figure, 1 is
A closed container composed of a tank part 2 and a lid part 3, and the closed container 1 is filled with a cleaning liquid 4 such as a cleaning agent or water used in a conventional alternative cleaning method. , An electronic component 5 such as a hybrid IC is immersed. The electronic component 5 is, for example, a component 7 mounted on the surface of a substrate 6 and fixed by soldering. A gap portion 8 is formed between the substrate 6 and the component 7.

Bubbles 9 are often formed in the gap portion 8, and the air pressure inside the closed container 1 is passed through the holes of the tank 2.
For example, if the pressure is reduced to about 10 to 100 mmHg, the bubbles 9 are likely to rise, the bubbles 9 in the gap portion 8 escape, and the cleaning liquid 4 easily enters the gap portion. Therefore, the flux attached to the gap portion 8 can be removed.

On the contrary, the atmospheric pressure in the closed container 1 is, for example,
If the pressure is increased to about 1500 mmHg, the volume of the bubbles 9 in the gap portion 8 becomes smaller, and the cleaning liquid 4 is added to the gap portion 8 by that amount.
Becomes easier to enter. Therefore, the flux attached to the gap portion 8 can be removed.

In the above embodiment, the electronic component 5
The component 7 is mounted on the substrate 6, but the configuration is not limited to this, and any component may be used. Further, in the embodiment, depressurization and pressurization were performed in the closed container 1, but not limited to the closed container, for example, the tank portion 2 in a small chamber.
May be arranged and the atmospheric pressure in the small chamber may be reduced or increased.

[0014]

As described above, the electronic component cleaning method of the present invention can enhance the cleaning performance of the electronic component by cleaning under reduced pressure or pressure. Therefore, the transition to the alternative cleaning method can be facilitated without degrading the quality of the electronic component.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a method of cleaning an electronic component according to the present invention.

[Explanation of symbols]

 1 Airtight container 2 Tank part 3 Lid part 4 Cleaning liquid 5 Electronic parts 6 Board 7 Parts 8 Gap part 9 Bubbles

Claims (1)

[Claims] 1. A method of cleaning an electronic component, which comprises immersing the electronic component in a cleaning liquid and cleaning the electronic component under reduced pressure or pressure.