JP3201048B2 - Plasma cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma cleaning apparatus used for cleaning the surface of many small articles made of metal or nonmetal such as plastic or glass.

[0002]

2. Description of the Related Art An object to be processed is placed in a vacuum chamber, while plasma is generated in a plasma generator outside the vacuum chamber, and a plasma gas is guided from the plasma generator through an introduction pipe into the vacuum chamber. Is ejected from an ejection port provided on one side of the vacuum chamber, and the other side of the vacuum chamber is evacuated so that the plasma gas flows through the vacuum chamber. There is an apparatus that performs plasma cleaning of an object to be processed by touching the surface (for example, see Japanese Patent Application Laid-Open No. Sho 62-15233). According to such an apparatus, by arranging a large number of small objects to be processed in one layer and keeping them in the vacuum chamber, there is a feature that plasma cleaning of the surface of the objects can be appropriately performed.

[0003]

However, according to this conventional technique, when a large number of the objects to be treated are put in a multilayer shape in order to improve the efficiency of the apparatus, it is difficult for the plasma gas to flow through the intermediate layer. Therefore, there has been a problem that a large number of objects to be processed cannot be cleaned by plasma.

The present invention has been made in order to solve the above-mentioned problems (technical problems) of the prior art. In this state, many objects to be processed are stacked or juxtaposed in a plurality of spaces in a vacuum chamber. It is an object of the present invention to provide a plasma cleaning apparatus that can uniformly perform plasma cleaning even if it is inserted, and can greatly improve efficiency.

[0005]

In order to achieve the above-mentioned object, a plasma cleaning apparatus according to the present invention is provided between a plurality of spaces for holding an object to be processed in a vacuum chamber.
Electrodes are provided to make the space for their existence a plasma atmosphere.

[0006]

When an object to be processed is placed in each of a plurality of spaces in a vacuum chamber and plasma is generated by an electrode between the spaces, each space becomes a plasma atmosphere, and each of the spaces becomes a plasma atmosphere. Plasma cleaning can be performed by contacting any of the processing objects with a plasma atmosphere.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 4, reference numeral 1 denotes a vacuum chamber, which is made of, for example, stainless steel. Reference numeral 2 denotes a doorway of the object to be processed in the chamber, which is provided with a sealable door 3. Reference numeral 4 denotes a plurality of spaces in the chamber for storing an object to be processed. Reference numeral 5 denotes an exhaust port provided in a part of the chamber 1 and an exhaust duct (for example, a metal flexible pipe).
6 is connected to a vacuum exhaust device (not shown). Next, reference numeral 8 denotes an electrode for changing the storage space to a plasma atmosphere.
Each of them is formed in a plate shape, and is arranged between the storage spaces 4 and above the uppermost storage space 4 and below the lowermost storage space 4. These electrodes 8 are supported by a support 9 shown in FIG. In the supporting state, the vacuum chamber 1 is electrically insulated. The electrode 8 is made of a porous material such as stainless steel punching metal so that a process gas can flow therethrough. Numeral 10 denotes a cooling means provided in each of the plasma generating electrodes 8, for example, a pipe for passing cooling water. Numeral 11 is a member for taking over the cooling water to the cooling means 10 of each electrode, for example, a nylon tube is used.
In FIG. 2, reference numeral 12 denotes a current-carrying electrode connected to the plurality of electrodes 8, 13 denotes a member for insulating and sealing between the electrode 12 and the vacuum chamber 1, and 14 denotes a power supply for plasma generation, , For example, a high frequency (also called a radio wave, the frequency of which is 13.56 MHz, for example). 15 is a matching device. Although not shown, a supply pipe for feeding a process gas for a plasma atmosphere is connected to the inside of the vacuum chamber 1.

[0008] Next, reference numeral 17 denotes means for carrying in and out the object to be processed into and out of the storage space 4, and is exemplified by a bogie. Reference numeral 18 denotes a pedestal portion of the carriage, which has wheels 19 on a lower surface.
Reference numeral 20 denotes a support fixed to the pedestal portion 18, and reference numeral 21 denotes a receiving shelf attached to the support 20, which is connected to each other by the support 20 at a portion other than a portion overlapping with the electrode 8 in a plan view to form an integral unit. ing. Reference numeral 22 denotes a member for holding the object to be processed.
1 illustrates a basket fixedly or detachably mounted on a basket. The members indicated by reference numerals 18 to 22 are formed of a conductive material such as stainless steel or another metal material so that the vacuum chamber 1 and the basket 22 are electrically connected.

Next, a description will be given of a process of plasma cleaning of a large number of small objects to be processed by the plasma cleaning apparatus having the above-described configuration.
Examples of the object to be processed include small parts made of synthetic resin such as a polyester cap for a relay and various metal products such as a relay contact. The objects to be processed as described above are denoted by reference numerals in FIG.
As shown at 23, each basket 22 is put in a bulk state, for example. In this state, the door 3 of the vacuum chamber 1 is opened, and the cart 17 on which the object 23 is placed is loaded into the chamber 1 from the entrance 2. In this case, each basket
Each of the large number of objects 23 to be processed placed on the
To enter. Next, the door 3 is closed, and the inside of the chamber 1 is evacuated by the evacuation device. Further, while the evacuation is continued, a process gas such as oxygen is supplied to the chamber 1 at a suitable pressure for plasma generation, for example, 0.3 to 3 mba.
r. Then, a current is supplied to each electrode 8 from the power source 14 for plasma generation through the matching unit 15 to perform a plasma discharge at each electrode 8. Due to this discharge, the process gas is turned into plasma, and the storage space 4 becomes a low-temperature plasma atmosphere. A large number of objects 23 are subjected to plasma cleaning called plasma processing such as degreasing, activating the surface, and reducing oxides (eg, removing rust) by plasma cleaning in the plasma atmosphere. If a predetermined time has elapsed in this state, the introduction of the process gas and the energization to the electrode 8 are stopped, and then the pressure in the vacuum chamber 1 is returned to the atmospheric pressure by, for example, air. Thereafter, the door 3 is opened, and the workpiece 23 which has been processed is carried out by the carriage 17.

In the above-described plasma cleaning apparatus, the plurality of electrodes 8 and the plurality of receiving shelves 21 are configured to be detachable from the support 9 and the columns 20, respectively. A storage space having a size corresponding to the size of the object to be processed may be ensured.

Next, FIG. 5 is a longitudinal sectional view showing a different embodiment of the present invention. In this embodiment, a plurality of spaces 4e for holding objects to be processed are provided in a state of being arranged side by side, and are provided in a state of hanging down from above. The plasma generating electrode 8e is located between these spaces. In addition, portions that are considered to have the same or equivalent configuration as those in the previous figure in terms of function are denoted by the same reference numerals as in the previous figure with the letter e, and redundant description is omitted.

Next, a further example of the positional relationship between a plurality of spaces for storing objects to be processed and plasma generating electrodes provided between the spaces will be described. And a cylindrical electrode may be arranged between these spaces.

[0013]

As described above, according to the present invention, when the surface of a large number of small objects 23 is subjected to plasma cleaning, the surface of the object 23 is exposed to a plasma atmosphere to perform plasma cleaning there. Of course, in the above case, the plurality of small objects to be processed can be properly placed in the plurality of spaces 4, 4,...
Even if the space 23 is inserted, each of the spaces 4 can have an appropriate plasma atmosphere, and the plasma cleaning of a large number of small objects 23 can be uniformly performed in each space. There is an effect that the efficiency of the cleaning device can be significantly improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view.

FIG. 2 is a schematic diagram showing a longitudinal section.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV in FIG. 2;

FIG. 5 is a schematic longitudinal sectional view showing a different embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 4 Space for storage 8 Electrode for plasma generation

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23G 5/00 B29C 71/00 C08J 7/00

Claims (1)

(57) [Claims] 1. A plasma cleaning apparatus comprising: an electrode provided between a plurality of spaces in a vacuum chamber for storing an object to be processed;