JP3207638B2 - Semiconductor manufacturing apparatus cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus for forming a fine pattern of a semiconductor device, for example.
In particular, it relates to a cleaning method for dry-cleaning the semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Microwave processing, reactive ion etching and the like are known as fine processing techniques for semiconductor devices. The reactive ion etching includes a method using a parallel plate electrode, a method using ECR (cyclotron resonance), and the like.

FIG. 2 shows a conventional reactive ion etching apparatus using parallel plate electrodes. The reaction processing chamber 10 is made of, for example, aluminum or an aluminum alloy. A part of the reaction processing chamber 10 may be made of aluminum or an aluminum alloy.
An upper electrode 11 constituting a parallel plate electrode made of an aluminum alloy is provided at an upper portion of the reaction processing chamber 10, and a lower electrode 12 is provided inside the reaction processing chamber 10. The inner wall 21 of the reaction chamber 10 is usually treated with aluminum alumite or coated with a ceramic made of Al ₂ O _{3 in} order to prevent contamination from the aluminum base material. The upper electrode 11 is grounded, and the inside is hollow. An introduction pipe 13 for introducing a reaction gas is provided on the upper surface of the upper electrode 11, and a plurality of through holes 14 for introducing the reaction gas into the reaction processing chamber 10 are provided on the lower surface. On the lower electrode 12, an object 15 such as a silicon wafer is placed.
The lower electrode 12 is connected to a high frequency power supply 17 via a blocking capacitor 16. Reaction processing chamber 1
Inside the lower electrode 12, a baffle plate 18 is provided around the lower electrode 12, and the baffle plate 18 is provided with a plurality of through holes 19. Further, an exhaust pipe 20 is provided on a side surface of the reaction processing chamber 10.

In the above structure, when the object to be processed 15 is etched, a reaction gas is introduced into the inside of the reaction processing chamber 19 through the plurality of through holes 14 of the upper electrode 11 and exhausted from the exhaust pipe 20. The pressure in the reaction processing chamber 10 is controlled. At the same time, high-frequency power is supplied from the high-frequency power supply 17 to the lower electrode 12 to generate plasma between the upper electrode 11 and the lower electrode 12,
The film to be etched of the object to be processed 15 is etched. At this time, aluminum, alumite, and the like on the inner wall 21 of the reaction processing chamber 10 exposed to the plasma are simultaneously etched.

[0005]

In the conventional semiconductor processing apparatus, the upper electrode 11 and the lower electrode 1
2, a fluorine-based gas such as CHF ₃ , CF ₄ ,
The SF _{6 and the} like are turned into plasma, and the object 15 is subjected to plasma processing. Therefore, not only the object 15 but also the reaction chamber 1
Even the inner wall material of 0 is etched. The reaction product of AlF ₃ generated at this time has a very low vapor pressure, so that it is difficult to be exhausted, and a phenomenon that the reaction product is deposited 21 on the inner wall of the reaction processing chamber 10 occurs. These reaction products become thicker with time for each treatment and become a source of particles.

Conventionally, in order to remove the above reaction products, a method has been adopted in which the reaction processing chamber 10 is opened to the atmosphere and physically wiped. However, since the film quality of the reaction product is very strong, it has been difficult to completely remove it.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to remove a reaction product deposited on an inner wall of a reaction processing chamber while maintaining the reaction processing chamber in a vacuum state. An object of the present invention is to provide a method of cleaning a semiconductor manufacturing apparatus, which can be removed and dust generated due to a reaction product can be prevented.

[0008]

In order to solve the above-mentioned problems, the present invention introduces a gas containing at least one kind of fluorine into a reaction processing chamber at least partially composed of aluminum or an aluminum alloy. A semiconductor manufacturing apparatus for processing a target object by converting a gas into plasma, wherein at least one kind of chlorine-based or bromine-based gas is introduced into the reaction processing chamber, and the gas is converted into a plasma to process the target object. Accordingly, the reaction product having a low vapor pressure generated in the reaction processing chamber is replaced with a substance having a high vapor pressure and exhausted.

[0009]

According to the present invention, a chlorine-based or bromine-based gas is introduced into a reaction processing chamber using aluminum as a base material, the gas is turned into plasma, and a dust source generated when processing an object to be processed is provided. The reaction product having a low vapor pressure is replaced with a substance having a high vapor pressure and exhausted. For this reason, the reaction product deposited on the inner wall of the reaction processing chamber can be removed without opening the reaction processing chamber to the atmosphere, and dust generation due to the reaction product can be prevented.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as those in FIG. 2 are denoted by the same reference numerals. In FIG. 1, when the object to be processed is an insulating film formed on a silicon wafer, CHF ₃ , C
Plasma etching is performed using a fluorine-based gas such as F ₄ or C ₂ F ₆ alone, or a mixed gas with another additive gas. These reaction gases are introduced into the reaction processing chamber 10 through the introduction pipe 13. The introduced gas is converted into plasma by high frequency power, and the plasma etches the insulating film on the silicon wafer. At this time,
Aluminum or alumite on the inner wall 21 of the reaction processing chamber 10 is also etched together with the object 15 to produce a low vapor pressure reaction product such as AlF ₃ shown in FIG. This reaction product is deposited on the inner wall of the reaction processing chamber 10. These films deposited over time are peeled off from the inner wall 21 of the reaction processing chamber 10 by being exposed to the stress of the film itself or the plasma, thereby causing particles.

In this embodiment, before the reaction product is peeled off from the inner wall of the reaction processing chamber 10, the reaction processing chamber 10 is subjected to plasma processing for cleaning different from the original plasma processing (hereinafter referred to as cleaning processing). Call). The interval between the cleaning processes is performed, for example, at a frequency of 2 hours with respect to the original plasma processing of 10 hours. In the cleaning process, the cleaning gas 23 is used.
Is introduced from the introduction pipe 13 into the reaction processing chamber 10. As the cleaning gas 23, a chlorine (Cl) gas, for example, a Cl ₂ gas is used.

The cleaning Cl ₂ gas introduced into the reaction processing chamber 10 through the introduction pipe 13 is turned into plasma by high frequency power supplied to the lower electrode 12. For this reason, the reaction product of AlF ₃ deposited on the inner wall of the reaction processing chamber 10 in the original plasma processing is changed to a substance of AlCl ₃ by the plasma processing using Cl ₂ gas. As is well known, this AlCl ₃ is a gas having a high vapor pressure and is a substance that is easily vaporized and exhausted. Therefore, exhaust can be easily performed from the exhaust pipe 20.

According to the above-described embodiment, the plasma processing is performed in the reaction processing chamber 10 with the Cl-based gas at a predetermined interval from the original plasma processing, so that the reaction product having a low vapor pressure is converted into a substance having a high vapor pressure. Has been replaced and discharged. Therefore, the atmosphere in the reaction processing chamber 10 can always be kept clean and dust generation can be prevented.

Further, according to the method of this embodiment, it is not necessary to open the reaction processing chamber to the atmosphere at the time of cleaning the reaction processing chamber. The room can be cleaned. Therefore, the cleaning operation is easier than before.

FIG. 3 shows the number of processed objects and the dust generation in the reaction chamber 10 before and after performing the original plasma processing. One wafer is processed every time 25 wafers are processed. The amount of dust per unit was measured. When the original plasma processing is continuously performed without performing the cleaning processing using the Cl-based gas, the dust generation shows a very unstable transition. In contrast, when the original plasma processing is performed for, for example, 10 hours, that is, when the cleaning processing is performed for 2 hours every time 100 wafers are processed, the amount of generated dust is stable at a very low level.

In the above embodiment, the case where the present invention is applied to a dry etching apparatus of a balanced flat plate has been described. However, the present invention is not limited to this. It is needless to say that the present invention is effective for all apparatuses for performing the reaction treatment.

The gas used for the plasma treatment for cleaning is not limited to Cl ₂ gas, but may be a compound gas with Cl typified by BCl ₃ or the like. Further, AlF ₃ can be converted to a gas having a high vapor pressure by using a halogen gas other than Cl-based gas, for example, a bromine-based (Br-based) gas.
Since the substance changes to lBr ₃ , the same effect as in the above embodiment can be obtained. Of course, various modifications can be made without departing from the scope of the present invention.

[0018]

As described above in detail, according to the present invention, it is possible to remove the reaction products deposited on the inner wall of the reaction processing chamber while keeping the reaction processing chamber in a vacuum state. And a method for cleaning a semiconductor manufacturing apparatus capable of preventing dust generation due to the above.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a method of the present invention.

FIG. 2 is a configuration diagram showing a conventional reactive ion etching apparatus.

FIG. 3 is a diagram showing a change in the amount of dust generation depending on the presence or absence of cleaning in a reaction processing chamber.

[Explanation of symbols]

10: reaction processing chamber, 11: upper electrode, 12: lower electrode,
13: introduction pipe, 15: object to be processed, 17: high-frequency power source, 20: exhaust pipe, 23: cleaning gas.

Claims (3)

(57) [Claims] 1. A semiconductor manufacturing apparatus for introducing a gas containing at least one kind of fluorine into a reaction processing chamber at least partly made of aluminum or an aluminum alloy, turning the gas into plasma, and processing an object to be processed. And introducing at least one kind of chlorine-based or bromine-based gas into the reaction processing chamber and converting the gas into plasma, and accumulating the low-vapor-pressure reaction product in the reaction processing chamber along with the processing of the object to be processed. A method for cleaning a semiconductor manufacturing apparatus, wherein a gas having a high vapor pressure is replaced and exhausted. 2. The method for cleaning a semiconductor manufacturing apparatus according to claim 1, wherein said aluminum or aluminum alloy is subjected to aluminum alumite treatment. 3. The method according to claim 1, wherein at least part of the aluminum or aluminum
In a reaction chamber made of aluminum alloy,
At least one type of gas containing fluorine is introduced, and this gas
Semiconductor manufacturing equipment that processes the object by converting it into plasma
And at least one chlorine-based or odor
Introduce elemental gas and turn this gas into plasma
Generated in the reaction chamber due to the processing of the object to be processed.
Exhaust by replacing low vapor pressure reaction products with high vapor pressure substances
Is allowed, the cleaning of the reaction chamber by the chlorine or bromine-based gas, the cleaning method of the semi-conductor manufacturing apparatus you and performing 2 hours original processing every 10 hours with a fluorine gas.