JPH07130704A - Apparatus and method of plasma treatment - Google Patents

Abstract

PURPOSE:To provide an apparatus and a method of plasma treatment, which suppresses an increase in contamination or removes it in a short time in a treatment chamber without opening the chamber to the atmosphere. CONSTITUTION:A cleaning gas is supplied from an inlet opening 7. In a plasma treatment system 6, the pressure is held at a given level by adjusting a vacuum apparatus 9, and a high-frequency power supply 12 at a power of 300W is used to generate plasma. Then, a switch 4 is turned to the side of a high-frequency AC power supply 2 to supply a high-frequency alternating current to a conductor 1 put along an inside wall of the plasma treatment system 6 so that a contamination 5 attached to the inside wall can be removed in the plasma treatment system 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and method for cleaning the inner wall of a plasma processing apparatus such as dry etching and plasma CVD.

[0002]

2. Description of the Related Art In recent years, as an example of a method for cleaning an inner wall of a plasma processing apparatus, (1) a method of repeatedly supplying and exhausting air in a processing chamber, (2) a method of using plasma irradiation, and (3) disassembling the plasma processing apparatus. Cleaning methods are often used.

Of the above-mentioned conventional methods for cleaning the inner wall of the plasma processing apparatus, referring to the drawings, (1)
A method of repeating air supply and exhaust in the processing chamber and (2) a method of using plasma irradiation will be described.

FIG. 2 is a schematic view of a conventional plasma processing apparatus. In FIG. 2, 5 is a foreign substance, 6 is a plasma processing device, 7 is an air supply port, 8 is an exhaust port, 9 is a vacuum device,
Reference numeral 10 is an anode, 11 is a cathode, and 12 is a high frequency power source for plasma generation.

The operation of the cleaning method of the inner wall of the plasma processing apparatus constructed as above will be described below.

First, (1) Regarding the method of repeating air supply and exhaust in the processing chamber, gas is supplied from the air supply port 7 and the exhaust port 8 together with the foreign matter 5 retained in the plasma processing apparatus 6 is exhausted.
Cleaning is advanced by exhausting air from.

Next, regarding the method (2) using plasma irradiation, the cleaning gas introduced from the air supply port 7 is activated by the influence of plasma to become radicals, and adheres to the inner wall of the plasma processing apparatus 6. The cleaning proceeds by reacting with the foreign matter 5 present and exhausting the reaction product from the exhaust port 8.

[0008]

However, the above-mentioned structure has a problem that the yield in manufacturing is reduced due to the influence of foreign matter for the following reason.

(1) In the method of repeating the supply and exhaust of the air in the processing chamber, the influence of the gas flow path is great, and it is impossible to remove the foreign matter existing in the so-called gas reservoir which is not in the gas flow path. Therefore, the amount of foreign matter increases in the processing chamber.

(2) In the method using plasma irradiation, the material inside the processing chamber is damaged due to excessive plasma irradiation, and foreign matter is completely removed in a short time due to insufficient cleaning in the area where plasma does not go around. Is impossible.

(3) The method of disassembling and cleaning the plasma processing apparatus cannot be applied to a plasma processing apparatus in which it is difficult to open the processing chamber to the atmosphere due to the use of dangerous gas, and is complicated. In the case of a plasma processing apparatus having such a structure or in which it is difficult to attach and detach the components, the inner wall of the processing chamber cannot be sufficiently cleaned, and the number of foreign matters immediately after cleaning increases sharply.

In view of the above problems, the present invention is directed to a plasma processing apparatus for suppressing the increase of foreign substances in the processing chamber or completely removing the foreign substances in a short time without exposing the processing chamber to the atmosphere. It provides a method.

[0013]

In order to solve the above problems, in the plasma processing apparatus of the present invention, in the plasma processing apparatus, an insulating material is provided along the inner wall of the processing chamber excluding the sample stage and the electrode, the outer wall or the inside of the wall. And a high frequency AC power supply and a DC power supply connected in parallel to both ends of the coil, and a means for supplying power by arbitrarily switching the high frequency AC power supply and the DC power supply.

Next, in the plasma processing apparatus of the present invention, a coil covered with an insulating material along the inner wall of the processing chamber, the outer wall, or the inside of the wall excluding the sample stage and the electrodes is connected in parallel to both ends of the coil. In a plasma processing apparatus equipped with a high-frequency AC power supply and a DC power supply, and means for supplying power by arbitrarily switching the high-frequency AC power supply and the DC power supply, a DC current is passed through the coil during plasma processing, and a high-frequency power is supplied to the coil during cleaning. It is designed to pass an alternating current.

[0015]

The present invention has the above-described structure. First, during plasma processing, a direct current is passed through a coil provided on the inner wall of the processing chamber to generate heat due to the electric resistance generated in the conductor. Prevents foreign substances from adhering to the inner wall of the processing chamber. Next, during cleaning, energy is released in a direction perpendicular to the conductor by passing a high-frequency alternating current through a coil provided on the inner wall of the processing chamber, and a reaction between foreign matter adhering to the inner wall of the processing chamber and the cleaning gas is promoted. Therefore, the foreign matter attached to the inner wall of the processing chamber can be completely removed in a short time.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A plasma processing apparatus and method according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a plasma processing apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a coil, 2 is a high frequency alternating current power source, 3 is a direct current power source, 4 is a power source switching switch, 5 is a foreign substance, 6 is a plasma processing apparatus, 7
Is an air supply port, 8 is an exhaust port, 9 is a vacuum device, 10 is an anode, 1
Reference numeral 1 is a cathode, and 12 is a high frequency power source for plasma generation.

The operation of the plasma processing apparatus and method configured as above will be described below with reference to FIG.

First, in the operation during the plasma processing, the process gas is introduced from the air supply port 7, the pressure in the plasma processing apparatus 6 is adjusted by the vacuum apparatus 9, and the high frequency power source 12 for plasma generation is operated. Generate plasma. At this time, the power source switching switch 4 is switched to the DC power source 3 side, and the coil 1 provided along the inner wall of the plasma processing apparatus 6
A DC current is passed through to prevent the volatile foreign matter 5 from adhering during the plasma processing.

Next, the operation during cleaning is
O ₂ gas is supplied from the air supply port 7 as a cleaning gas to 10
0 sccm is introduced, and the pressure in the plasma processing apparatus 6 is 10
The vacuum device 9 is adjusted so as to keep it at 0 mTorr, and the high frequency power source 12 for plasma generation is set to 300 W (13.56 MH).
z) to generate plasma. At this time, the power source switching switch 4 is switched to the high frequency AC power source 2 side, and the high frequency AC current (50 W, 13.56 MHz) is passed through the coil 1 provided along the inner wall of the plasma processing apparatus 6 to cause the inner wall of the plasma processing apparatus 6 to pass. The foreign matter 5 adhering to is removed by reaction.

As described above, according to the present embodiment, during the plasma processing, a direct current is passed through the coil provided on the inner wall of the processing chamber to generate heat due to the electric resistance generated in the conductor, so that the volatile gas is generated. It is possible to prevent high substances from adhering to the inner wall of the processing chamber as foreign matter. Next, during cleaning, energy is released in a direction perpendicular to the conductor by passing a high-frequency alternating current through a coil provided on the inner wall of the processing chamber, and a reaction between foreign matter adhering to the inner wall of the processing chamber and the cleaning gas is promoted. Therefore, the foreign matter adhering to the inner wall of the processing chamber can be completely removed in a short time.

In the present embodiment, the parallel plate RIE apparatus is used as the plasma processing apparatus, but the same effect can be obtained with any specifications as long as the apparatus uses plasma, such as magnetron RIE and ECR apparatus. Is obtained.

Next, a high-frequency AC power supply with a drive frequency of 13.56 MHz was used. This has a frequency (about 100 kHz to about 50 MHz) that can be guided by a coaxial cable.
Needless to say, it is good if it is Hz).

Next, by making the coil removable from the inner wall of the processing chamber, the effect of facilitating the replacement and maintenance of parts of the coil itself can be obtained.

Further, a material having a high electric resistance (Cu alloy or Ni—Cr alloy) may be used as the material of the conductor forming the coil, and a material having high plasma resistance may be used as the insulating material covering the conductor forming the coil. The wiring method such as the winding method of the conductor forming the coil, the number of turns, the shape, and the number of cores is not particularly limited.

Further, O ₂ gas was used as a gas used during the cleaning, but this is at least O ₂ , S.
It goes without saying that any mixed gas containing any one of F ₆ , NF ₃ and ClF ₃ may be used.

[0027]

As described above, according to the present invention, during plasma processing, direct current is passed through the coil provided on the inner wall of the processing chamber to generate heat due to the electric resistance generated in the conductor, which is highly volatile. It is possible to prevent the substance from adhering to the inner wall of the processing chamber as a foreign substance. Next, during cleaning, energy is released in a direction perpendicular to the conductor by passing a high-frequency alternating current through a coil provided on the inner wall of the processing chamber, and a reaction between foreign matter adhering to the inner wall of the processing chamber and the cleaning gas is promoted. Therefore, the foreign matter adhering to the inner wall of the processing chamber can be completely removed in a short time.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a plasma processing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a conventional plasma processing apparatus.

[Explanation of symbols]

 1 coil 2 high frequency alternating current power supply 3 direct current power supply 4 power supply changeover switch 5 foreign matter 6 plasma processing device 7 air supply port 8 exhaust port 9 vacuum device 10 anode 11 cathode 12 high frequency power supply for plasma generation

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H01L 21/304 341 D 21/31 H01L 21/31 C

Claims (8)

[Claims] 1. In a plasma processing apparatus, a coil covered with an insulating material along a processing chamber inner wall, outer wall or inside the wall excluding a sample stage and an electrode, and a high frequency AC power source connected in parallel to both ends of the coil. A plasma processing apparatus comprising: a DC power supply; and a means for supplying power by arbitrarily switching the high frequency AC power supply and the DC power supply. 2. A coil provided along the inner wall of the processing chamber,
The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is removable from the inner wall of the processing chamber. 3. The driving frequency of the high frequency AC power source is about 100.
The plasma processing apparatus of claim 1, wherein the frequency is between kHz and about 50 MHz. 4. A material of a conductor forming a coil, Cu
The plasma processing apparatus according to claim 1, wherein an alloy or a Ni-Cr alloy is used. 5. A plasma processing apparatus according to claim 1, wherein ceramic or alumina is used as an insulating material for covering the conductor forming the coil. 6. A coil covered with an insulating material along the inner wall, outer wall or inside of the processing chamber excluding the sample stage and the electrodes, and a high frequency AC power supply and a DC power supply connected in parallel to both ends of the coil. A plasma processing apparatus comprising means for supplying electric power by arbitrarily switching between the high frequency alternating current power supply and the direct current power supply, wherein a direct current is passed through the coil during plasma processing, and a high frequency alternating current is passed through the coil during cleaning. Plasma processing method. 7. The plasma processing method according to claim 6, wherein the plasma processing and the cleaning are alternately performed. 8. The plasma processing method according to claim 6, wherein a mixed gas containing at least one of O ₂ , SF ₆ , NF ₃ , and ClF ₃ is used as a gas used during cleaning.