JPH0423823B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plasma processing apparatus capable of gasifying and exhausting reaction products adhering to the inner wall of a plasma processing chamber when plasma processing is performed on an object to be processed. It is something.

First, the configuration of a conventional plasma processing apparatus having parallel plate electrodes will be explained, and then problems with its cleaning method will be explained.

FIG. 1 is a block diagram of a conventional plasma processing apparatus having parallel plate electrodes. In the processing chamber 1, there are provided a mounting electrode 2 on which an object to be processed is placed and a counter electrode 4 facing the mounting electrode 2. The mounting electrode 2 is insulated from the processing chamber 1 by an insulating material 3, and connected to a high frequency power source. The counter electrode 4 and the processing chamber are grounded. The inside of the processing chamber 1 is exhausted from an exhaust port 6, and processing gas is supplied from a gas supply port 7.

When performing plasma treatment using this device, a high frequency voltage is applied to the mounting electrode 6 from the high frequency power source 5,
Since plasma is generated between the electrodes as shown in the plasma region 8, reaction products adhere to the inner wall of the processing chamber 1 and the back side of the counter electrode 4, which are not exposed to the plasma. Conventionally, these reaction products have been removed by lowering the pressure inside the processing chamber, expanding the plasma region, and bringing the plasma into contact with the inner wall of the processing chamber. However, in such a method,
The main part of the plasma generated is between the parallel plates of both electrodes, which is the same as the plasma region 8 shown above, and the part where the plasma contacts the processing chamber wall is also limited as shown in the enlarged plasma generation region 9, so that the reaction does not occur. It was not possible to remove the product sufficiently.

Therefore, in the end, the processing chamber was opened to the atmosphere,
Cleaning must be done manually, which takes a lot of time, and since the processing chamber is opened to the atmosphere, moisture in the atmosphere is adsorbed on the walls of the processing chamber.
It took a long time, about 12 hours, to evacuate the processing chamber after cleaning. Furthermore, during plasma processing, moisture etc. are released from the wall surface, making the plasma processing itself unstable, and for example, it takes a day to reach a stable operating state.Therefore, conventional cleaning methods are difficult to maintain the stable operation and operation of the equipment. This was a major problem in trying to improve the rate.

An object of the present invention is to clean and remove reaction products that adhere to the side walls of a plasma processing chamber when plasma processing is performed on an object, without opening the plasma processing chamber to the atmosphere. Another object of the present invention is to provide a plasma processing apparatus that can automatically perform stable and high-quality plasma processing over almost the entire side wall of a plasma processing chamber.

That is, in order to achieve the above object, the present invention has the following features:
In a plasma processing apparatus that performs plasma processing on a workpiece placed on a mounting electrode installed in a plasma processing chamber, when plasma processing is performed on the workpiece, the inner wall of the plasma processing chamber A cleaning gas supply means for supplying a cleaning gas that reacts with the attached reaction products; and a cleaning gas supply means installed in the plasma processing chamber and applied by switching from ground to high frequency voltage by an electrical connection state switching means, and further plasma processing. A cleaning electrode having a side face facing a side wall of the chamber and having a length such that high-density plasma is generated in a gap with the side wall, and configured to move along the side wall,
A high-density plasma is generated by high-frequency discharge in the gap between the cleaning electrode and the grounded side wall of the plasma processing chamber, and the attached reaction products are generated over almost the entire side wall of the plasma processing chamber. This plasma processing apparatus is characterized by comprising a cleaning means for gasifying the object by reaction with the supplied cleaning gas and exhausting the gas.

An embodiment of the plasma processing apparatus of the present invention will be described below with reference to FIG. 2 of the drawings.

The processing chamber 1A has a body 10, a bottom lid 11, and an upper lid 1.
2, it has a sealed structure. An exhaust port 6 and a gas supply port 7 are attached to the body 10. The inside of the processing chamber 1A is evacuated from the exhaust port 6 by a vacuum pump (not shown), and processing gas and cleaning gas can be supplied from the gas supply port 7 from a supply device and a switching device (not shown). A mounting electrode 2 is fixed to the bottom lid 11 via an insulating material 3. A hole is made in the center of the upper lid 12, a bellows 13 is fixed around the hole, a circular ring 14 is fixed to the upper end of the bellows 13, and a screw with a cylindrical lower end is attached to the upper surface of the circular ring 14. A shaft 15 is attached. The threaded shaft 15 is attached to the upper lid 12
It is inserted into a hole in a support rod 16 fixed to the support rod 16, and above it is screwed into a female threaded hole in an upper and lower handle 17 to be supported.

A support rod for a counter electrode (cleaning electrode) 4A is fixed to the inside of the circular ring 14 above the bellows 13 via an insulating material 3. Therefore, the hole in the upper lid 12 has a bellows 13 and a circular ring 1.
4. It is sealed by the insulating material 3 and the supporting rod of the counter electrode 4A, and the counter electrode 4A is moved in a direction perpendicular to the mounting electrode 2 by turning the upper and lower handles 17.

The counter electrode 4A is placed on the mounting electrode 2 like a conventional electrode.
It has a surface 4a that faces and is parallel to and also faces the inner wall of the processing chamber 1A, that is, the body 10.

The mounting electrode 2 and the counter electrode 4A are connected to the changeover switch 1.
It is connected to the high frequency power source 5 and ground via 8. Further, the entire processing chamber 1A is also connected to ground potential.

Next, a method for cleaning a plasma processing apparatus according to the present invention will be explained based on an embodiment of the method for cleaning a plasma processing apparatus shown in FIG.

While the inside of the processing chamber 1A is evacuated from the exhaust port 6 by a vacuum pump (not shown), a cleaning gas, such as oxygen, is supplied from the gas supply pipe 7. By operating the changeover switch 18, the mounting electrode 2 is connected to the ground, and the counter electrode 4A is connected to the high frequency power source 5.

After setting the above conditions, when you turn on the high frequency power supply, not only between the counter electrode 4A and the mounting electrode 2,
High-density plasma is generated between the inner walls of the body 10 and over almost the entire surface between the back surface of the counter electrode 4A and the upper lid 12, and the plasma causes reaction products attached to the entire inner wall of the processing chamber. reacts with the supplied cleaning gas such as oxygen, gasifies it, and exhausts it from the exhaust port 6, cleaning the entire processing chamber. In particular, by forming the portion 4a parallel to the grounded body 10 on the counter electrode 4A to which a high-frequency voltage is applied, a considerable amount of area facing the body 10 is obtained, and the area 4a of the counter electrode 4A is It is possible to generate a strong high-density plasma in the gap between the part and the body 10, and further, by rotating the upper and lower handles 17, the counter electrode 4A, that is, 4a of the counter electrode 4A can be generated.
By moving the part up and down, it is possible to generate high-density plasma over the entire inner wall of the body 10, and the reaction products adhering to the entire inner wall of the body 10 are replaced by the supplied oxygen. It can be cleaned by reacting with a cleaning gas such as gas and gasifying it.

As explained above, according to the present invention, it is possible to generate high-density plasma over almost the entire side wall of the plasma processing chamber in the plasma processing apparatus, and as a result, more plasma adheres to the side wall of the plasma processing chamber. The generated reaction products can be cleaned almost automatically without exposing the plasma processing chamber to the atmosphere, which improves the availability rate and stable operation of the plasma processing equipment, and also ensures stable high quality. This has the advantage that plasma processing can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional plasma processing apparatus, and FIG. 2 is a sectional view of an embodiment of the plasma processing apparatus of the present invention. 1,1A...processing chamber, 2...mounting electrode, 3...
Insulating material, 4,4A... counter electrode, 5... high frequency power supply, 6... exhaust port, 7... gas supply port, 13...
Bellows, 15... threaded shaft, 17... upper and lower handles, 18... selector switch.

Claims (1)

[Claims] 1 In a plasma processing apparatus that performs plasma processing on a workpiece placed on a mounting electrode installed in a plasma processing chamber, when plasma processing is performed on the workpiece, the inner wall of the plasma processing chamber a cleaning gas supply means for supplying a cleaning gas that reacts with the reaction product attached to the cleaning gas;
A length that is installed in the plasma processing chamber, is applied by switching from ground to high frequency voltage by the electrical coupling state switching means, and is further opposed to the side wall of the plasma processing chamber to generate high-density plasma in the gap between the side wall and the side wall. and a cleaning electrode configured to move along the side wall, and a gap between the cleaning electrode and the grounded side wall of the plasma processing chamber over almost the entire surface, and a high-frequency discharge. A cleaning means for generating high-density plasma to gasify and exhaust reaction products adhering to almost the entire side wall of the plasma processing chamber by reaction with the supplied cleaning gas. Characteristic plasma processing equipment.