JP3055888B2 - Plasma processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma processing method in a plasma processing apparatus.

[0002]

2. Description of the Related Art A plasma processing apparatus which performs processing by plasma generated in a plasma processing chamber by microwaves radiated into a plasma processing chamber from a slot formed in a cavity resonance chamber is disclosed in Japanese Patent Application Laid-Open No. HEI 10-163556. 63-
A plasma processing apparatus disclosed in JP 103088 and JP-A-63-263725 has been proposed.

In general, when a microwave travels through a waveguide or a cavity resonator considered to be a kind of waveguide, a current corresponding to an electric field and a magnetic field flows on the surface of the waveguide.
When a slit-shaped hole is provided in a part of the waveguide so as to cross this current, electric charge accumulates at both ends of this hole, and this changes as the microwave advances, so the electric field between both ends of the hole changes Then, the microwave is radiated outside the waveguide. This is the principle of a slot antenna used for a microwave element, and the slit-shaped hole is called a slot.

A plasma processing apparatus using such a principle has, for example, a configuration as shown in FIG. The microwave oscillated by the magnetron 3 is introduced into the cavity 1 through the waveguide 2, passes through the microwave window provided on the lower surface of the cavity 1, and passes through the slot 4 to be processed. Is radiated to the plasma processing chamber 7 to which the processing gas is supplied, and excites the processing gas to generate plasma.

At this time, if the etching gas is supplied to the plasma processing chamber, the etching process can be performed on the substrate 6, and if the CVD gas is supplied, the substrate 6 can be etched.
Can be subjected to a thin film forming process.

For example, when a thin film is formed, SiH ₄ , N
CV of ₂ O, Si (OC ₂ H ₅ ) ₄ O ₂ , NH ₃ , N _2, etc.
D gas is introduced, microwaves oscillated by the magnetron 3 are radiated into the plasma processing chamber 7 through the microwave window 5 and the slit 4, and the CVD gas is excited to generate plasma to form a thin film on the substrate 6. I do.

In such a thin film forming step, when a thin film is formed on the substrate 6, the same thin film as the thin film formed on the substrate 6 is also formed on the inner wall of the plasma processing chamber 7. Therefore, when a thin film is continuously formed on many substrates 6, the thin film is deposited on the inner wall of the plasma processing chamber 7. Then, when the thin film deposited on the inner wall of the plasma processing chamber 7 becomes thick to some extent, a part of the thin film peels off from the inner wall. At this time, if the substrate 6 is being processed, the thin film peeled off from the inner wall may adhere to the substrate 6 as dust.

Therefore, when a thin film is formed on a substrate by a plasma processing apparatus, it is necessary to periodically clean the plasma processing chamber to remove the thin film deposited on the inner wall of the plasma processing chamber. This cleaning operation is usually performed by plasma etching. That is, while supplying an etching gas such as CF ₄ and NF ₃ into the plasma processing chamber, a microwave is introduced to generate a plasma of the etching gas, and a thin film deposited in the plasma processing chamber is removed by etching.

[0009]

In a plasma processing apparatus in which a microwave is introduced to generate plasma, as shown in FIG. 3, although there is a difference depending on the pressure in the plasma processing chamber, a cavity resonator is used. The density of the generated plasma differs depending on the distance X from the microwave window (quartz plate) that partitions the plasma processing chamber from the plasma processing chamber. Since the etching rate is proportional to the density of the plasma, the etching rate varies depending on the location in the plasma processing chamber. In particular, a large amount of time is required for cleaning on the substrate mounting table and its peripheral portion, and the workability and the plasma processing apparatus are increased. Cause the operating rate to decrease.

In view of the above circumstances, an object of the present invention is to provide a plasma processing method capable of rapidly cleaning the inside of a plasma processing chamber and improving workability and an operation rate of a plasma processing apparatus. is there.

[0011]

In order to achieve the above object, according to a first aspect of the present invention, there is provided a container for forming a plasma processing chamber, means for evacuating the container to a vacuum, Means for supplying a processing gas to the container, first plasma generating means for generating plasma in the container, and an inner wall of the plasma processing chamber, which is electrically insulated and covers the inner surface of the container. And a second plasma generating means for applying high-frequency power from the power source to the electrode to generate plasma on the surface of the electrode. A plasma processing method for performing plasma processing on a substrate to be processed disposed inside the container using a processing apparatus, wherein the inside of the container is evacuated to a vacuum, and a processing gas is supplied to the inside of the container. The plasma generating means, plasma is generated on the surface of the electrode to clean the surface of the electrode, the surface of the electrodes is generated by the first plasma generator inside the cleaning plasma processing chamber plasma The plasma processing is performed on the substrate to be processed.

Further, in the second invention, a container forming a plasma processing chamber, a unit for evacuating the container to a vacuum, a unit for supplying a processing gas into the container, First plasma generating means for generating;
The container is provided with an electrode that is electrically insulated and covers the inner surface of the container and forms an inner wall of the plasma processing chamber, and a power supply that supplies high-frequency power to the electrode. A plasma processing method for performing plasma processing on a substrate to be processed disposed inside the container by using a plasma processing apparatus provided with second plasma generating means for generating plasma on a surface of the electrode by applying power. Evacuating the inside of the container to a vacuum, supplying a processing gas into the container, generating plasma in the plasma processing chamber by the first plasma generating means, and generating the plasma by the second plasma generating means. A plasma is generated on the surface of the electrode to clean the surface of the electrode.
The substrate to be processed is subjected to plasma processing by the plasma generated by the first plasma generating means inside the plasma processing chamber whose surface has been cleaned.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front sectional view of a plasma processing apparatus embodying the present invention.

In FIG. 1, reference numeral 1 denotes an E ₀₁ mode cavity resonator through which microwaves are introduced from a magnetron 3 through a waveguide 2. Reference numeral 4 denotes a slot formed on the bottom surface of the cavity resonator 1. The cavity resonator 1 and the magnetron 3 constitute a first plasma generating means.

Reference numeral 7a denotes a container which forms a plasma processing chamber 7. Reference numeral 8 denotes a substrate mounting table, which is disposed in the plasma processing chamber 7 via an insulator 20b and is connected to a high-frequency power supply 12b. Reference numeral 6 denotes a substrate, which is mounted on a substrate mounting table 8 during processing such as thin film formation and etching.

Reference numeral 20a denotes an insulator, which is formed of an insulator such as alumina ceramics and is fixed to the inner surface of the container 7a. Reference numeral 11 denotes an electrode, which is fixed to the inner surface of the container 7a via an insulator 20a, forms an inner wall of the plasma processing chamber 7, and is connected to a high frequency power supply 12a. The electrode 11 and the high frequency power supply 12a constitute a second plasma generator.

Reference numeral 10 denotes a processing gas inlet formed in the container 7a and connected to the outlet 10b via a flow path 10a formed in the container 7a, the insulator 20a and the electrode 11. Reference numeral 9 denotes an exhaust port formed in the container 7a and connected to a vacuum exhaust means (not shown). 5 is a microwave window,
It is arranged between the cavity resonator 1 and the electrode 11.

In such a configuration, when cleaning the inside of the plasma processing apparatus, after the substrate 6 is taken out, the inside of the plasma processing chamber 7 is evacuated via the exhaust port 9 and sent from the introduction port 10. An etching gas is blown into the plasma processing chamber 7 from the blowout port 10b, and high-frequency power is applied to the electrode 11 from the high-frequency power supply 12a.

Then, the etching gas supplied into the plasma processing chamber 7 is excited by the high frequency power, and
A plasma is generated near 1. Then, the surface of the electrode 11 (that is, the plasma processing chamber 7) is generated by this plasma.
Cleaning that etches and removes the thin film deposited on the inner wall).

Further, the plasma processing chamber 7 is
The inside of the plasma processing chamber 7 is evacuated and the etching gas sent from the inlet 10 is blown out from the outlet 10b.
The microwaves emitted from the magnetron 3 are radiated into the plasma processing chamber 7, and high-frequency power is applied to the electrodes 11 from the high-frequency power supply 12a, so that the dispersion of the density is simultaneously small over the entire surface of the cleaning target area. If the plasma is generated, the etching can proceed simultaneously at high speed over the entire area to be cleaned, so that the cleaning time can be reduced.

[0021]

As described above, according to the present invention, the plasma processing chamber can be quickly cleaned, and the workability and the operation rate of the plasma processing apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a plasma processing apparatus embodying the present invention.

FIG. 2 is a partially cutaway perspective view of a conventional plasma processing apparatus.

FIG. 3 is a characteristic diagram showing a density distribution of plasma.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... cavity resonator, 2 ... waveguide, 3 ... magnetron, 4 ...
Slot: 5: Microwave window, 6: Substrate, 7: Plasma processing chamber, 8: Substrate mounting table, 11: Electrode, 12a: High frequency power supply, 20a: Insulator.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 C23F 4/00-4/04 H01L 21/205 H01L 21/3065 H01L 21/31

Claims (2)

(57) [Claims] A container for forming a plasma processing chamber; a unit for evacuating the container to a vacuum; a unit for supplying a processing gas into the container; and a first unit for generating plasma in the container.
A plasma generating means, the vessel is electrically insulated and arranged to cover the inner surface of the vessel, comprising an electrode forming an inner wall of the plasma processing chamber, and a power supply for supplying high-frequency power to the electrode, Plasma processing is performed on a substrate to be processed disposed inside the container using a plasma processing apparatus provided with second plasma generating means for generating high-frequency power from the power source to the electrode to generate plasma on the surface of the electrode. A plasma processing method, wherein the inside of the container is evacuated to a vacuum, a processing gas is supplied to the inside of the container, and plasma is generated on the surface of the electrode by the second plasma generating means. Clean the surface, the surface of the electrode
The first but in the interior of the cleaning plasma processing chamber
A plasma processing method for the substrate to be processed using plasma generated by the plasma generating means. 2. A container forming a plasma processing chamber, means for evacuating the container to a vacuum, means for supplying a processing gas into the container, and a first means for generating plasma in the container.
A plasma generating means, the vessel is electrically insulated and arranged to cover the inner surface of the vessel, comprising an electrode forming an inner wall of the plasma processing chamber, and a power supply for supplying high-frequency power to the electrode, Plasma processing is performed on a substrate to be processed disposed inside the container using a plasma processing apparatus provided with second plasma generating means for generating high-frequency power from the power source to the electrode to generate plasma on the surface of the electrode. A plasma processing method, wherein the inside of the container is evacuated to a vacuum, a processing gas is supplied into the container, plasma is generated in a plasma processing chamber by the first plasma generating means, and the second by generating plasma on the surface of the electrode by plasma generation means to clean the surface of the electrode, of the plasma processing chamber in which the surface of the electrode is cleaned In plasma processing method, which comprises plasma treating the substrate to be processed by said generated in the first plasma generating means plasma.