JPH01140724A - Plasma treatment apparatus - Google Patents

Abstract

PURPOSE:To clean and remove a substance adhered to a wall face in a whole region inside a treatment chamber including a gap part sandwiched between an earth shielding body and an inner wall of the treatment chamber by a method wherein a plasma is generated in the gap part. CONSTITUTION:A changeover switch 9 is connected to a side a; a gas which is effective for a cleaning operation is introduced into a treatment chamber 1 from a gas source 1b, and is adjusted to a prescribed pressure. When high-frequency electric power is impressed not only on a cathode electrode 8 but also on an earth shielding body 5 and an anode electrode 3 from a high-frequency power supply 8, a plasma is generated at a gap part between them and an inner wall of the grounded treatment chamber 1. Accordingly, the plasma is generated in a whole region inside the treatment chamber 1 ; in addition, because both the earth shielding body 5 and the anode electrode 3 become substantially at the same potential as the cathode electrode, it is possible to obtain ion energy which is necessary and sufficient for the cleaning operation. By this setup, it is possible to easily clean and remove a substance which has adhered to a wall face in a part sandwiched between the earth shielding body 5 and the treatment chamber 1 by the use of the plasma.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to dry etching equipment, plasma CVD equipment, etc. that process samples using plasma, and in particular to cleaning and removing substances attached to the inside of a processing chamber using plasma. The present invention relates to a plasma processing method and apparatus suitable for this purpose.

[Conventional technology]

Conventionally, when cleaning and removing substances adhering to the inner wall of the processing chamber using plasma L, the polarity of the upper and lower electrodes was changed.

The cleaning effect is further improved. In other words, it is the energy of the ions in the plasma that are incident on the grounded anode electrode.

Since the energy is extremely small compared to the energy of ions incident on the cathode electrode to which high-frequency power is applied, reaction products tend to accumulate. For this reason, the polarity is sometimes switched and the deposited substances are cleaned and removed by plasma. (!
! #Kai No. 57-42151.

reference).

[Problem that the invention seeks to solve]

In the case of the above-mentioned conventional technology, the back and outer surfaces of the electrode connected to the high-frequency power source are usually surrounded by a grounded earth shield, so that there is no space between the electrode connected to the high-frequency power source and the processing chamber wall. The structure is designed to prevent the generation of sheet electricity. Therefore, regardless of whether the polarity of the upper and lower electrodes is switched, plasma is not generated in the gap between the earth shield body and the processing chamber wall. Therefore, there is a problem in that the substances deposited on the surface of this area cannot be cleaned and removed by plasma.

An object of the present invention is to generate plasma also in the gap between the earth shield body and the processing chamber wall only during cleaning and removal, and to clean and remove the deposits attached to this area.

[Means for solving problems]

The above purpose is the earth shield body and processing room! The device is configured to be electrically insulated and connected to a high frequency power source and the ground via a changeover switch.When installing, the earth shield body is connected to the high frequency power source using a changeover switch, and high frequency power is applied to the earth shield body. This is achieved by applying Note that during normal plasma processing, the earth shield body may be grounded using a changeover switch.

[Effect]

By applying high frequency power to the earth shield body using the changeover switch, plasma is generated between the earth shield body and the grounded processing chamber, since the earth shield body in principle forms a part of the cathode electrode.

This makes it possible to efficiently (clean and remove) substances attached to the back surface of the earth shield body.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows the case of a cathode-coupled dry etching device. A cathode electrode 2 is provided at the bottom of the grounded processing chamber 1. At the top is an anode.

Provide pole 5. The cathode electrode 2 is surrounded by an insulator 4 and a conductive earth shield 5. The earth shield body 5 and the processing chamber 1 are made of an insulator 6.

electrically isolated. Anode electrode 5 and treatment.

The display 1 is also insulated with an insulator 7. cathode electrode.

A high frequency power source 8 is connected to 2. Further, the cathode electrode 2 and the anode electrode 5 are connected by a cable.

One is connected to the other via the selector switch 9.

High frequency power supply 8. The other end is connected to ground 10.

A pipe connected to an etching gas source 11a outside the processing chamber 1 is guided into the processing chamber 1 via a mass flow controller 12α.

On the other hand, the piping connected to the gas source 11b is guided to the back cavity of the cathode electrode 2 and the anode electrode 5 via the mass flow controller 12A. In the above configuration, its operation will be explained.

Etching gas is introduced into the processing chamber 1 and the cathode '1 pole 2
between the electrodes by applying VC high frequency power.

Plasma is generated to etch the wafer 15. Note that the changeover switch 9 is brought into contact with the b side. A part of the reaction products generated during etching are deposited on the inner wall of the processing chamber 1 and on the anode electrode 5. It adheres and accumulates on the back surface of the earth shield body 5. This substance is fast.

This not only becomes a source of foreign matter, but also causes deterioration of etching characteristics due to the desorption of the storage gas. Therefore, it is necessary to periodically carry out cleaning inside the processing chamber 1. In this case, the changeover switch 9 is connected to the α side, a gas effective for cleaning such as q or CF4 is introduced into the processing chamber 1 from the gas source 11A, and a predetermined power ICv4 is applied. High frequency power supply 8
When high frequency power is applied not only to the cathode electrode 8 but also to the earth shield body 5 and the anode electrode 5, plasma is generated in the gap between these and the grounded inner wall of the processing chamber 1. Therefore, plasma is generated throughout the interior of the processing chamber 1, and moreover, the earth shield body 5. Since both the anode electrode 5 and the cathode electrode have substantially the same potential, sufficient ion energy necessary for cleaning can be obtained. As a result, substances deposited on the wall surface of the narrow portion of the earth shield body 5 and the processing chamber 1Vc can be easily cleaned and removed by plasma. As described above, according to this embodiment, processing chamber 1
The entire area inside the processing chamber 1, especially the area narrowed between the earth shield body 5 and the inner wall of the processing chamber 1, can be easily and effectively cleaned and removed by plasma.

Note that by directly introducing the cleaning gas into the gap between the earth shield body 5 and the anode electrode 5 and the processing chamber 1, the cleaning effect can be further improved.

FIG. 2 shows another embodiment. This example shows the case of an anode-coupled dry etching apparatus. The configuration 0 effect is approximately equivalent to the example of FIG.

However, a case is shown in which the processing chamber 1b is made of an insulating material such as quartz.

FIG. 5 shows a microwave dry etching device as an embodiment of WJ5. In this example, microwaves generated by a magnetron 21 are guided to a plasma chamber 25 through a waveguide 22, and the plasma density within the plasma chamber 25 is greatly increased by the magnetic field of a coil 24, thereby realizing high performance. However, in this case as well, no plasma is generated in the gap between the process chamber 1 and the earth shield body 5 attached to the outside of the electrode 25 on which the wafer is placed. This example also uses the same method as the example shown in FIG.

Apply force and clean to this area.

By introducing the gas, there is an effect that the entire area of the processing chamber 1 can be cleaned by plasma.

〔Effect of the invention〕

According to the invention, the earth shield body and the processing chamber.

Since plasma can be generated even in the voids narrowed by the walls, there is an effect that substances adhering to the walls in the entire range of values in the processing chamber including these regions can be cleaned and removed.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a longitudinal sectional view of another embodiment, and FIG. 5 is a longitudinal sectional view of still another embodiment. DESCRIPTION OF SYMBOLS 1... Processing chamber, 2... Cathode electrode, 3... Anode electrode, 4, 6.7... Insulator, 5... Earth shield body, 8... High frequency power supply, 9... - Selector switch, 25...electrode. 1st flash 5z A is alone - I Redo and Tol Figure '5

Claims (1)

[Claims] 1. In a device that introduces gas into a processing chamber, supplies high-frequency power to generate plasma, and processes a sample with this plasma, the back and side surfaces of the electrode to which the high-frequency power source is connected are surrounded. The earth shield body is electrically insulated from the earth and the grounded processing chamber, and the earth shield body is configured to be selectively connected to either the high frequency power source or the earth via a changeover switch. Plasma processing equipment.