JP2885150B2 - Dry cleaning method for dry etching equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dry etching method used in a manufacturing process of a semiconductor device, in particular those about the dry cleaning how aluminum dry etching device.

[0002]

2. Description of the Related Art In recent years, with the increase in the density and fine pattern of semiconductor devices, dust generation in a manufacturing apparatus, particularly in a reaction chamber, greatly affects product yield.
Therefore, it is required to establish a dry cleaning technique which is a measure for preventing dust generation in the reaction chamber.

In a dry etching apparatus, as the number of times of processing a wafer as a semiconductor substrate increases, a reaction product is gradually generated and deposited in a reaction chamber, and the deposition amount tends to increase. In particular, a reaction product is generated around the cathode electrode and the anode electrode surface in the reaction chamber, and a large amount of the reaction product adheres and deposits on the inner wall of the reaction chamber. These reaction products are peeled off and scattered in the reaction chamber due to a change in temperature in the reaction chamber, which causes dust.

Recently, an electrostatic attraction stage utilizing an electrostatic attraction force has been generally adopted as a method for holding a wafer. However, when a reaction product is deposited around a cathode electrode, particularly at the electrostatic attraction stage, the wafer is held. A small gap is formed by the reaction product between the reaction chamber and the electrostatic adsorption stage, and the temperature control gas in the reaction chamber is leaked through this gap to change the temperature inside the reaction chamber, and the wafer is processed. This has the effect of causing product failure.

FIG. 2 is a schematic sectional view showing the structure of the dry etching apparatus. 2. Description of the Related Art Conventionally, as shown in FIG. 2, this type of dry etching apparatus has a cathode electrode 3 disposed facing a reaction chamber 10 of a reaction chamber 1 which is a vacuum vessel.
13.5 between high-frequency power supply 9 and
A high-frequency power of 6 MHz is applied, and a reaction gas, for example, a chlorine gas or a boron chloride gas introduced into the reaction chamber 1 is turned into a plasma to form a cathode electrode 3 and an anode electrode 6.
And a gas plasma 11 is formed between
The thin film of the wafer (not shown) mounted on the wafer stage 4 of the cathode electrode 3 is etched with high precision by ions and radicals as active components therein. In the drawing, reference numeral 5 denotes a gas blowing plate, 7 denotes a ground, and 8 denotes a gas supply port. A reaction gas from the gas supply port 8 is introduced between the cathode electrode 3 and the anode electrode 6 from the gas blowing plate 5. I was

In a conventional dry etching apparatus, the electrode spacing between the cathode electrode 3 and the anode electrode 6 is fixedly set within a range of about 150 mm to 200 mm, and chlorine gas or boron chloride, which is an etching reaction gas, is supplied to the cathode electrode 3. Cl ₂ / BCl ₃ = 10 between anode electrode 6
Plasma was generated by flowing 0/20 SCCM, thereby removing a resist-based reaction product generated in the reaction chamber to perform cleaning.

[0007]

BRIEF Problem to be Solved] Conventionally, as a method for cleaning the reaction chamber 1, in addition to dry cleaning method using C1 ₂ / BCl ₃ plasma such as noted above, the reaction chamber 1 Was released to the atmospheric pressure state, and a wet cleaning method using alcohol, pure water, or the like was employed.

However, in the above-described wet cleaning method, it is necessary to return the internal pressure of the reaction chamber 1 to the atmospheric pressure, and it takes a long time to open the atmosphere to the atmosphere, so that it takes a long time to clean the reaction chamber. there were. In the dry cleaning method, C
Because of the l ₂ / BCl ₃ plasma, aluminum chloride-based reaction products can be removed, but resist-based reaction products are difficult to remove. In the etching of aluminum, the amount of reaction-based reaction products generated is larger than that of aluminum chloride.
For this reason, it is required to efficiently remove resist-based reaction products.

In the dry etching method, Cl ₂ /
Since the surface of the cathode electrode 3 is etched by the BCl ₃ plasma, it is necessary to perform the processing while the wafer is placed on the wafer stage 4 for the purpose of protecting the cathode electrode 3. There is a problem that it is difficult to remove the reaction products deposited around.

An object of the present invention, provides in view of the above conventional problems, the peripheral cathode electrode, dry cleaning how the dry etching apparatus products adhering deposited in a large amount to the anode electrode can be efficiently removed Is to do.

[0011]

In order to achieve the above object, a dry cleaning method for a dry etching apparatus according to the present invention comprises generating plasma between a cathode electrode and an anode electrode facing a reaction chamber of a reaction chamber. A dry cleaning method for a dry etching apparatus for performing an etching process by setting a facing gap between a cathode electrode and an anode electrode facing each other.
The cathode electrode and the anode electrode during the etching process.
When removing the reaction product deposited on the pole,
The distance between the cathode electrode and the anode electrode corresponding to the distance
The distance between the cathode and anode electrodes is set to be small.
The reaction product is introduced by introducing ozone gas into
It is to be removed.

[0012]

[0013]

[0014]

[0015]

In the dry cleaning method of the dry etching apparatus according to the present invention, the interval between the cathode electrode and the anode electrode is made narrower than the interval at the time of the etching process, and ozone (O ₃ ) gas is introduced into this narrow space. Ozone gas is brought into contact with the reaction product on the anode electrode or the like to incinerate and remove. At this time, the process is performed without placing a wafer on the cathode electrode.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a dry etching apparatus having a dry cleaning function according to an embodiment of the present invention.

In FIG. 1, a dry cleaning apparatus provided in a dry etching apparatus according to the present invention basically has a pair of a cathode electrode 3 and an anode electrode 6 forming a pair.
And a gap adjusting unit 13 and the ozone generator 12.

A pair of cathode electrode 3 and anode electrode 6
Is an electrode used for the dry etching process, and the cathode electrode 3 and the anode electrode 6 are installed facing each other in the reaction chamber 10 of the reaction chamber 1. Specifically, the anode electrode 6 is fixedly installed downward on the ceiling side of the reaction chamber 10, and the cathode electrode 3 is arranged below the anode electrode 6 and upward. Further, the cathode electrode 3 has a shaft portion 3a extending downward. The shaft portion 3a is drawn out of the reaction chamber 1, and the cathode electrode 3 moves up and down to form an anode electrode 6, a cathode electrode 3 Is adjusted by switching between a wide gap interval during the etching operation (gap interval shown in FIG. 2) and a narrow gap interval during the dry cleaning operation (gap interval in FIG. 1).

A gas blowout plate 5 is mounted on the anode electrode 6 side, and a wafer stage 4 is mounted on the cathode electrode 3 side.
Is installed. The gas blowout plate 5 is connected to the cathode electrode 3
A gas supply port 8 is connected to the gas blow-out plate 5, and the gas supply port 8 is connected to a reaction gas supply source (not shown). ing.

Further, of the shaft portions 3a of the cathode electrode 3, the shaft portions 3a protruding outside the reaction chamber 1
3, the gap adjusting unit 13 is connected to the cathode 3
Is moved up and down to adjust the gap between the electrodes 3 and 6. The shaft 3a of the cathode electrode 3
The sliding portion between the chamber and the reaction chamber 1 is hermetically sealed.

An ozone generator 12 is connected to the gas supply port 8 of the gas blowing plate 5. Ozone generator 12
Generates ozone (O ₃ ) gas and reacts
Is to be introduced within. Ozone generator 1
No. 2 controls and supplies the ozone gas introduction amount.

Next, the dry cleaning method of the present invention will be described. 13.56 MHz from a high-frequency power supply 9 between a cathode electrode 3 and an anode electrode 6 disposed facing each other in a reaction chamber 10 of a reaction chamber 1 which is a vacuum vessel.
Is applied, and a reaction gas, for example, a chlorine gas or a boron chloride gas introduced into the reaction chamber 1 is turned into plasma to form a gas plasma between the cathode electrode 3 and the anode electrode 6 (see FIG. 2). The thin film of a wafer (not shown) mounted on the wafer stage 4 of the cathode electrode 3, particularly aluminum, is dry-etched by ions, radicals and the like, which are active components in the gas plasma. In this case, a resist-based reaction product is gradually generated and deposited in the reaction chamber 1. During the etching process, 150
It is set to a wide interval of up to 200 mm. During the etching process, the electrode interval between the cathode electrode 3 and the anode electrode 6 is set to a wide interval of 150 to 200 mm.

In the present invention, the cathode electrode 3 and the anode electrode 6 are used during the dry cleaning process by using the gap adjusting unit 13.
The gap between the electrodes is adjusted by raising the cathode electrode 3 toward the anode electrode 6 so that the electrode interval is narrower than the set value at the time of the etching process, specifically, about 2 mm.

Next, an ozone (O ₃ ) gas is generated by an ozone generator 12 and supplied to a gas blow-out plate 5 through a gas supply port 8. By introducing ozone gas into the space between the electrodes 6, the ozone gas is brought into contact with a resist-based reaction product deposited on the electrode and its surroundings in a narrow space between the electrodes 3 and 6, thereby removing the reaction product. And vacuum outlet 2
Discharged from

Ozone gas of 2000 sccm is introduced into the space between the cathode electrode 3 and the anode electrode 6 at a further smaller interval.
And the large amount of ozone gas is brought into contact with the reaction product to promote the incineration of the reaction product.

Further, a large amount of ozone gas is introduced between the cathode electrode 3 and the anode electrode 6 having a small interval to increase the flow rate of the ozone gas between the electrodes 3 and 6, and the ashed reaction product is removed from the electrodes 3 and 6. And from the surrounding area.

Further, the semiconductor substrate is removed from the electrodes, and the asode electrode, the cathode electrode and the periphery thereof are subjected to dry cleaning.

FIG. 3 shows the transition of the gap between the cathode electrode and the anode electrode and the rate of removal of the reaction product. In FIG. 3, based on the case where the electrode interval between the cathode electrode 3 and the anode electrode 6 during the etching process is set to a wide interval of 150 to 200 mm, the interval was gradually narrowed, and the state of removal of the reaction product was observed. As a result,
It was found that the gap between the cathode electrode 3 and the anode electrode 6, which is effective for removing the reaction product, may be set to 2 mm. In this example, the electrode interval between the cathode electrode 3 and the anode electrode 6 during the etching process is set to 150 to 200 mm. If the electrode interval between the cathode electrode 3 and the anode electrode 6 during the etching process is changed, The gap between the cathode electrode 3 and the anode electrode 6, which is effective for removing the reaction products, is also changed.
The gap between the anode electrodes 6 is not limited to 2 mm.

[0030]

As described above, according to the present invention, the interval between the cathode electrode and the anode electrode is made narrower than that at the time of the etching process, and ozone (O ₃ ) gas is introduced into a narrow space between the electrodes. To contact the reaction product
Reaction products generated around the cathode electrode and on the anode electrode surface can be efficiently removed, so that a significant cleaning effect can be obtained as compared with the conventional dry cleaning method, thereby shortening the cleaning time and consequently reducing the operation rate of the apparatus. It can be greatly improved.

Further, since a Cl ₂ / BCl ₃ plasma is not used and an ozone (O ₃ ) gas is used, the wafer is placed on the electrode for the purpose of protecting the cathode electrode without etching the surface of the cathode electrode. Te process there is no need to perform around the cathode electrode can be particularly reliably removed until the reaction products deposited around the wafer stage to adsorb the wafer.

Further, according to the present dry cleaning method, dry cleaning can be performed in a state where a wafer is not placed on the cathode electrode. Therefore, the dry cleaning method can be performed during a wafer processing process, and contamination in the reaction chamber can be reduced. In addition, the number of continuously processed wafers can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a dry etching apparatus having a dry cleaning function according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional dry etching apparatus.

FIG. 3 is a diagram showing a change in a removal rate of a resist-based reaction product obtained from an experimental result obtained by performing dry cleaning by changing an electrode interval arbitrarily.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Vacuum exhaust port 3 Cathode electrode 4 Wafer stage 5 Gas blowout plate 6 Anode electrode 7 Ground 8 Gas supply port 9 High frequency power supply 10 Reaction chamber 11 Plasma 12 Ozone generator 13 Gap adjusting part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/3065 H01L 21/205

Claims (1)

(57) [Claims] 1. A dry cleaning method for a dry etching apparatus for performing an etching process by generating plasma between a cathode electrode and an anode electrode facing a reaction chamber of a reaction chamber, wherein the facing cathode electrode and the anode electrode are separated by a predetermined amount. In the gap
Perform the etching process by setting, the cathode electrode and the anode electrode during the etching process
When removing the reaction products deposited on the
Corresponding to the distance between the cathode electrode and the anode electrode
Narrowly set, guiding the ozone gas between the cathode electrode and the anode electrode
A dry cleaning method for a dry etching apparatus , wherein the reaction product is removed.