JPH09115879A - Dry cleaning method for dry etching system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove reaction products deposited in large quantities efficiently by setting the interval between opposing cathode electrode and anode electrode shorter as compared with the etching time and bringing ozone gas into contact with reaction products in the limited space between the electrodes thereby removing the reaction products. SOLUTION: At the time of dry cleaning, a cathode electrode 3 is elevated toward an anode electrode 6 using an interval adjusting section 13 thus adjusting the interval. Ozone gas is then generated from an ozone generator 12 and fed through a gas supply port 8 to a gas diffuser 5 thence introduced into a limited space between the cathode electrode 3 and anode electrode 6. The ozone gas is brought into contact with resist based reaction products which are thereby removed and discharged through a vacuum discharge port 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry etching apparatus used in a semiconductor device manufacturing process, and more particularly to a dry cleaning method for an aluminum dry etching apparatus and the apparatus.

[0002]

2. Description of the Related Art In recent years, with the increase in density and fine patterns of semiconductor devices, dust generation in manufacturing equipment, especially in a reaction chamber, has a great influence on the yield of products.
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 a wafer, which is a semiconductor substrate, is processed increases, reaction products are gradually generated and deposited in the reaction chamber, and the amount of deposition tends to increase. In particular, a reaction product is generated around the cathode electrode or the surface of the anode electrode in the reaction chamber, or a large amount of the reaction product is attached and deposited on the inner wall of the reaction chamber. These reaction products are peeled off due to temperature changes in the reaction chamber and scattered into the reaction chamber, which causes dust generation.

Recently, an electrostatic adsorption stage utilizing electrostatic adsorption force has been generally adopted as a method for holding a wafer. However, when a reaction product is deposited around the cathode electrode, particularly on the electrostatic adsorption stage, the wafer is A minute gap is formed between the electrostatic adsorption stage and the electrostatic adsorption stage due to the reaction product, and the temperature control gas inside the reaction chamber leaks through this gap, changing the temperature inside the reaction chamber, and It will affect the product and cause defective products.

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, a dry etching apparatus of this type has a cathode electrode 3 which is arranged to face a reaction chamber 10 of a reaction chamber 1 which is a vacuum container.
13.5 between the anode electrode 6 and the high frequency power source 9
A high frequency power of 6 MHz is applied, and a reaction gas introduced into the reaction chamber 1, for example, a chlorine gas or a boron chloride gas is made into plasma to make the cathode electrode 3 and the anode electrode 6
A gas plasma 11 is formed between
The thin film of a wafer (not shown) mounted on the wafer stage 4 of the cathode electrode 3 is etched with high precision by ions and radicals which are active components therein. In the figure, 5 is a gas blowing plate, 7 is a ground, 8 is a gas supply port, and the reaction gas from the gas supply port 8 is introduced from the gas blowing plate 5 between the cathode electrode 3 and the anode electrode 6. Was there.

In the conventional dry etching apparatus, the cathode electrode 3 and the anode electrode 6 are fixedly installed with an electrode interval of about 150 mm to 200 mm, and chlorine gas or boron chloride as an etching reaction gas is used as the cathode electrode 3. CL2 / BC13 = 1 between the anode electrode 6
A plasma was generated by flowing 00/20 SCCM to remove the resist-based reaction product generated in the reaction chamber, thereby performing cleaning.

[0007]

Conventionally, as a method for cleaning the inside of the reaction chamber 1, in addition to the dry cleaning method using the CL2 / BC13 plasma as described above, the inside of the reaction chamber 1 has a large size. A wet cleaning method using alcohol, pure water, etc., which has been released to atmospheric pressure, has been adopted.

However, in the above-mentioned 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 it to the atmosphere. Therefore, it takes a long time to clean the reaction chamber. there were. In the dry cleaning method, C
Due to the L2 / BC13 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 the reaction product of the resist system is larger than that of the chloride system of aluminum, so that it is required to remove the reaction product of the resist system efficiently.

In the dry etching method, CL2 /
Since the surface of the cathode electrode 3 is etched by the BC13 plasma, it is necessary to perform 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 product deposited on the.

In view of the above-mentioned conventional problems, an object of the present invention is to provide a dry cleaning method and apparatus for a dry etching apparatus capable of efficiently removing a large amount of a product deposited and deposited around the cathode electrode and the anode electrode. To provide.

[0011]

In order to achieve the above object, a dry cleaning method for a dry etching apparatus according to the present invention comprises a plasma generation between a cathode electrode and an anode electrode facing a reaction chamber of a reaction chamber. In a dry etching device that performs etching processing by
By setting the gap between the facing cathode electrode and the anode electrode to be narrower than that during the etching process, and by introducing ozone gas between the cathode electrode and the anode electrode having a narrow gap,
The ozone gas is brought into contact with the reaction product in a narrow space between the electrodes to remove the reaction product.

Further, a large amount of ozone gas is brought into contact with the reaction product to promote ashing of the reaction product.

Further, a large amount of ozone gas is introduced between the cathode electrode and the anode electrode having a narrow interval to increase the gas flow velocity between the electrodes, and the ashed reaction product is swept from the electrode and its periphery. .

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

A dry cleaning apparatus in a dry etching apparatus according to the present invention is a dry cleaning apparatus in a dry etching apparatus having a pair of an anode electrode and a cathode electrode, a gap adjusting section, and an ozone generator. The anode and cathode electrodes are
The reaction chamber is installed in the reaction chamber so that the installation interval can be adjusted, and the gap adjusting unit adjusts the installation interval between the pair of anode electrode and cathode electrode during the dry cleaning operation to be narrower than the installation interval during the etching process. The ozone generator introduces ozone gas into the reaction chamber of the reaction chamber instead of the reaction gas.

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 that during the etching process, and ozone (O ₃ ) gas is introduced into this narrow space to form the cathode electrode. Ozone gas is brought into contact with the reaction product on the anode electrode to ash and remove it. At this time, processing is performed without placing the 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.

Referring to FIG. 1, the dry cleaning apparatus equipped in the dry etching apparatus according to the present invention has, as a basic structure, a cathode electrode 3 and an anode electrode 6 forming a pair.
And a gap adjusting part 13 and an ozone generator 12.

A pair of cathode electrode 3 and anode electrode 6
Is an electrode used in 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 fixed and 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 separate the anode electrode 6 and the cathode electrode 3 from each other. The gap spacing is adjusted to be a wide gap spacing during the etching operation (gap spacing shown in FIG. 2) and a narrow gap spacing during the dry cleaning operation (gap spacing in FIG. 1).

A gas blowing plate 5 is attached to the anode electrode 6 side, and a wafer stage 4 is attached to the cathode electrode 3 side.
Is installed. The gas blowing plate 5 is the cathode electrode 3
A reaction gas or ozone gas is introduced into the space between the anode electrode 6 and the anode electrode 6. A gas supply port 8 is connected to the gas blowing plate 5, and the gas supply port 8 is connected to a reaction gas supply source (not shown). ing.

Further, among the shaft portions 3a of the cathode electrode 3, the shaft portion 3a protruding outside the reaction chamber 1 is the gap adjusting portion 1
3, the gap adjusting portion 13 is connected to the cathode electrode 3
The shaft portion 3a is moved up and down to adjust the gap between the electrodes 3 and 6. The shaft portion 3a of the cathode electrode 3
The sliding portion between the reaction chamber 1 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 to cause reaction chamber 1
It is supposed to be introduced inside. Further ozone generator 1
2 supplies the ozone gas by controlling the introduction amount thereof.

Next, the dry cleaning method of the present invention will be described. A high-frequency power supply 9 is provided between the cathode electrode 3 and the anode electrode 6 facing each other in the reaction chamber 10 of the reaction chamber 1 which is a vacuum container to generate 13.56 MHz.
Of the reaction gas introduced into the reaction chamber 1, for example, chlorine gas or boron chloride gas to form plasma, thereby forming a gas plasma (see FIG. 2) between the cathode electrode 3 and the anode electrode 6, A thin film, notably aluminum, of a wafer (not shown) mounted on the wafer stage 4 of the cathode electrode 3 is dry-etched by ions or radicals which are active components in the gas plasma. In that case, a resist-based reaction product is gradually generated and deposited in the reaction chamber 1. Also, during the etching process, 150
It is set to a wide interval of ~ 200 mm. During the etching process, the electrode distance between the cathode electrode 3 and the anode electrode 6 is set to a wide distance of 150 to 200 mm.

In the present invention, the cathode electrode 3 and the anode electrode 6 are used by using the gap adjusting portion 13 during the dry cleaning process.
The gap between the electrodes is adjusted so as to be narrower than the set value during the etching process, specifically about 2 mm so that the cathode electrode 3 is raised toward the anode electrode 6 side.

Next, ozone (O ₃ ) gas is generated by the ozone generator 12, and this gas is supplied to the gas blowout plate 5 through the gas supply port 8. From the gas blowout plate 5, the cathode electrode 3 and the anode having a narrow interval are provided. By introducing ozone gas into the space between the electrodes 6, the ozone gas is brought into contact with the reaction products of the resist system deposited on the electrodes and the periphery thereof in the narrow space between the electrodes 3 and 6 to remove the reaction products. Vacuum outlet 2
Discharged from

In the space between the cathode electrode 3 and the anode electrode 6 having a narrower space, ozone gas is added at 2000 sccm.
Introduced to the extent of that, a large amount of ozone gas is brought into contact with the reaction product to promote ashing 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 narrow interval to increase the flow rate of the ozone gas between the electrodes 3 and 6, and the ashed reaction product is converted into the electrodes 3 and 6. And sweep around it.

Further, the semiconductor substrate is removed from the electrodes, and the associative electrode, the cathode electrode and their surroundings are subjected to a dry cleaning process.

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

[0030]

As described above, according to the present invention, the distance between the cathode electrode and the anode electrode is made narrower than that in the etching process, and ozone (O ₃ ) gas is introduced into the narrow space between the electrodes. To contact the reaction product,
The reaction products generated around the cathode electrode and on the anode electrode surface can be efficiently removed, and as a result, a cleaning effect can be significantly obtained compared to the conventional dry cleaning method, and the cleaning time can be shortened and the operation rate of the device can be improved. It can be greatly improved.

Further, since CL2 / BC13 plasma is not used and 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. It is possible to reliably remove even the reaction products deposited around the cathode electrode, particularly around the wafer stage that adsorbs the wafer.

Further, since the present dry cleaning method can perform the dry cleaning without placing the wafer on the cathode electrode, the dry cleaning can be performed between the wafer processing processes and the contamination in the reaction chamber can be reduced. The number of wafers to be continuously processed can be greatly improved.

[Brief description of 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.

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

FIG. 3 is a diagram showing a transition of a removal rate of a resist-based reaction product obtained from an experimental result of performing dry cleaning with an electrode interval arbitrarily changed.

[Explanation of symbols]

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

Claims (5)

[Claims] 1. In a dry etching apparatus which faces a reaction chamber of a reaction chamber and generates plasma between a cathode electrode and an anode electrode to perform an etching process, a gap between the facing cathode electrode and the anode electrode is etched. It is characterized in that ozone gas is introduced between the cathode electrode and the anode electrode, which are set to be narrower and the interval is narrower, so that the ozone gas is brought into contact with the reaction product in the narrow space between the electrodes to remove the reaction product. A dry cleaning method for a dry etching apparatus. 2. The dry cleaning method for a dry etching apparatus according to claim 1, wherein a large amount of ozone gas is brought into contact with the reaction product to promote ashing of the reaction product. 3. A large amount of ozone gas is introduced between a cathode electrode and an anode electrode, which are closely spaced, to increase the gas flow velocity between the electrodes, thereby sweeping ashed reaction products from the electrode and its periphery. The dry cleaning method of the dry etching apparatus according to claim 2. 4. The dry cleaning method for a dry etching apparatus according to claim 1, wherein the semiconductor substrate is removed from the electrodes and a dry cleaning process is performed on the associative electrode, the cathode electrode and the periphery thereof. 5. A dry cleaning apparatus in a dry etching apparatus having a pair of an anode electrode and a cathode electrode, a gap adjusting section, and an ozone generator, wherein the pair of the anode electrode and the cathode electrode is a reaction of a reaction chamber. It is installed in the room so that the installation interval can be adjusted, and the gap adjustment unit adjusts the installation interval of the anode electrode and the cathode electrode that make a pair during the dry cleaning operation to be narrower than the installation interval during the etching process. A dry cleaning apparatus in a dry etching apparatus, wherein the ozone generator introduces ozone gas into the reaction chamber of the reaction chamber instead of the reaction gas.