JPH0897185A - Production of semiconductor device - Google Patents

Abstract

PURPOSE: To remove carbon films at the corners of a reaction chamber or in the upper part of a shower and in the lower part of a susceptor or in an exhausting part as well as in the side wall part of the reaction chamber by removing the carbon films accumulating in the reaction chamber through film formation by using a gas for oxidizing reaction. CONSTITUTION: In a cleaning step after carbon film formation, a pressure in a reaction chamber 1 is set to normal pressure and the inside of the chamber 1 is heated at about 100 deg.C by a heater 3 prepared on the bottom of a susceptor 2, then an O3 gas is introduced into the chamber 1 to oxidize the carbon films. When the O3 gas spreads sufficiently in the chamber 1, the carbon films are oxidized thereby and are turned into a gas such as SiO2 , etc., then they are exhausted. Therefore, the carbon films at the corners of the reaction chamber or in the upper part of a shower and in the lower part of the susceptor or in the exhausting part as well as in the side wall part of the reaction chamber are removed and almost all of carbon films are removed in the reaction chamber as a result. Thus, any particle is prevented from generation during film formation thereafter, resulting in carbon films having an excellent film quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a MOS including a step of removing a carbon film adhering to a wall surface of a reaction chamber when forming a carbon film for forming an antireflection film. It can be applied to a method for manufacturing a semiconductor device such as a transistor and a bipolar transistor, and in particular, it can almost completely remove a carbon film in a reaction chamber, and can suppress the generation of particles during subsequent film formation, and has a good film quality. The present invention relates to a method for manufacturing a semiconductor device capable of obtaining the above carbon film.

In recent years, ultra-fine processing by i-line or excimer laser lithography has become important in the manufacturing process of 64M DRAM and the like. These lithography techniques require the formation of a carbon film effective as an antireflection film, and the carbon film to be the antireflection film is usually formed by a plasma CVD method or the like. However, when the carbon film is formed by the plasma CVD method as described above, the carbon film is deposited on the wall surface of the reaction chamber and the like, which causes particles at the time of subsequent film formation and deteriorates the quality of the formed film. is there.

Therefore, in order to remove the carbon film which causes the particles deposited on the wall surface of the reaction chamber or the like, a cleaning process by wet or dry may be performed, but in the former wet cleaning process, the wet process is performed. There is a problem that the reaction chamber must be decomposed and that it takes a long time to completely remove the carbon film by immersing it in a solution. For this reason, the dry cleaning process is drawing attention because it can increase the processing speed.

[0004]

2. Description of the Related Art Conventionally, when a plasma CVD carbon film is formed
The wet film is used to remove the carbon film deposited on the reaction chamber wall surface.
It has the advantage that the processing speed can be faster than the
Do O ₂Dry cream by plasma treatment using gas
Is being processed.

[0005]

However, in the conventional method of manufacturing a semiconductor device described above, as shown in FIG.
When the carbon film deposited on the wall surface of the reaction chamber 101 during the plasma CVD carbon film formation is treated with O ₂ gas plasma, the shower 102 and the heater 10 are provided between the upper electrode and the lower electrode.
Since plasma is generated between the susceptor 104 in which the No. 3 is built in, the upper part of the susceptor 104 and the reaction chamber
The carbon film on the first side can be removed efficiently, but since O ₂ plasma is less likely to wrap around between the shower 102 and the susceptor 104, the corner of the reaction chamber 101 and the shower 10
2 It is difficult to remove the carbon film on the upper part, the lower part of the susceptor 104, and the exhaust part. As a result, the plasma CVD after the plasma treatment is performed.
When the carbon film is formed, there is a problem that the residual carbon film is scattered as particles and enters the formed carbon film to deteriorate the film quality. This problem tends to become more prominent as the film formation is continuously repeated. In FIG. 6, 105 is an RF power supply.

Therefore, according to the present invention, not only the side wall of the reaction chamber but also the corners of the reaction chamber, the upper part of the shower, the lower part of the susceptor, and the exhaust part are removed to substantially completely remove the carbon film in the reaction chamber. Therefore, it is an object of the present invention to provide a method for manufacturing a semiconductor device, which can suppress the generation of particles during the subsequent film formation and can obtain a carbon film of good film quality.

[0007]

In order to achieve the above-mentioned object, the method of manufacturing a semiconductor device according to the present invention comprises oxidizing a carbon film deposited in a reaction chamber by a film-forming method with a gas for oxidizing the carbon film. It is characterized by including a step of removing. In the present invention, the carbon film forming method includes a radio frequency plasma CVD method, a microwave plasma CVD method, a sputtering method, a hot filament CVD method, and a direct current discharge plasma C.
A VD method, a plasma jet CVD method and the like can be mentioned.

As the gas for oxidizing the carbon film according to the present invention, at least one of O ₂ gas, O ₃ gas and H ₂ O gas is available, and the carbon film deposited in the reaction chamber is used. It is preferable in that it can be efficiently removed into a gaseous state such as CO ₂ through an oxidation reaction. The removal of the carbon film according to the present invention may be carried out under normal pressure or reduced pressure in the reaction chamber. If the former is carried out under normal pressure, the carbon film in the reaction chamber is subjected to oxidation reaction more than the latter case. Since the concentration of the generated gas can be increased, the rate of the oxidation reaction of the carbon film can be increased and the removal treatment speed can be increased, which is preferable. Further, the reaction chamber may be heat-treated (for example, 100 ° C. or higher). In this case, the oxidation reaction rate can be increased by activating the plasma in the reaction chamber and the surface to be treated of the carbon film, etc., as compared with the case of performing at room temperature. Therefore, it is preferable because the removal rate of the carbon film can be increased.

Next, in order to achieve the above object, the method for manufacturing a semiconductor device according to the present invention removes the carbon film deposited by the film forming method in the reaction chamber by plasma treatment using a gas containing at least oxygen atoms. And then coating the inside of the reaction chamber with a carbon film. In the present invention, the plasma treatment and the coating treatment may be performed in a single wafer. In this case, the plasma treatment and the coating treatment can be performed every time one wafer is formed.
This is preferable because the processing can be performed more efficiently than when the processing is performed after a number of wafers are continuously processed.

Examples of the carbon film forming method according to the present invention include a radio frequency plasma CVD method, a microwave plasma CVD method, a sputtering method, a hot filament CVD method, a direct current discharge plasma CVD method and a plasma jet CVD method. . Examples of the carbon film coating method according to the present invention include a plasma CVD method and a sputtering method. According to the former plasma CVD method, the reaction chamber wall surface is coated with a carbon film with better adhesion than when the sputtering method is used. It is possible and preferable.

The gas containing at least oxygen atoms according to the present invention includes O ₂ gas, O ₃ gas, N ₂ O gas and H ₂ O.
Gas, at least one of H ₂ O ₂ gas and CO ₂ gas
The seeds are preferable in that they can be obtained, handled, and can remove the carbon film deposited in the reaction chamber. In the present invention, the pressure during the plasma treatment is preferably 0.01 Torr or more and 2.0 Torr or less, and more preferably 0.1 to 0.5 Torr.
The carbon film on the susceptor just below the shower and the carbon film on the upper part of the shower can be efficiently removed. Pressure 0.0
When the pressure is less than 1 Torr, the etching rate of the carbon film on the susceptor is particularly lowered, and when the pressure is higher than 2.0 Torr, the etching rate of the carbon film on the shower upper part is lowered, which is not preferable.

In the present invention, the electrode interval between the upper electrode and the lower electrode during the plasma treatment is 10 mm or more and 100 or more.
It is preferable that the thickness is less than or equal to mm, and if it is within this range, the carbon film on the upper part of the susceptor and the carbon film on the lower side of the shower and the exhaust part on the side part of the susceptor can be efficiently removed. If the electrode interval is smaller than 10 mm, the etching rate of the carbon film in the exhaust portion is lowered, which is not preferable.
Further, if the electrode interval is larger than 100 mm, the etching rate of the carbon film on the susceptor lowers, which is not preferable.

In the present invention, it is preferable that the plasma treatment is performed at least twice or more by changing at least one of the pressure, the electrode interval and the frequency. In this case, for example, the electrode interval is 10 mm and the plasma treatment is performed. After that, when the plasma treatment is performed with the electrode interval set to 100 mm, the carbon film on the upper portion of the susceptor and the exhaust portion can be efficiently etched. Also, for example, a frequency of 200
After plasma treatment was performed at a frequency of 13.
When the plasma treatment is performed at 56 kHz, the carbon film on the side of the plasma reaction chamber and the exhaust portion can be efficiently etched. Further, for example, after performing plasma treatment with the pressure set to 0.1 Torr, the pressure is set to 0.5 (2.0) T
When the plasma treatment is performed at orrr, the carbon films on the upper portion of the shower and the upper portion of the susceptor can be efficiently etched. When the plasma treatment is performed by appropriately combining the appropriate values of the electrode spacing, the pressure and the frequency, the carbon film can be efficiently etched.

In the present invention, the coating film thickness of the carbon film is about 3000 angstroms in consideration of the coating ability, and even if the coating film thickness is made thicker than 3000 angstroms, the coating effect is improved so much. do not do. On the other hand, if the thickness is too thin, it becomes difficult to obtain the coating effect, which is not preferable.
The coating effect here is to cover fine particles that cause particles remaining on the wall surface of the reaction chamber after plasma treatment with a carbon film, and to disperse fine particles that become particles from the wall surface of the reaction chamber during film formation after coating. It means a function of preventing the film from adhering to the film formation surface.

[0015]

Conventionally, when the carbon film deposited on the wall surface of the reaction chamber is subjected to O ₂ plasma treatment, it is difficult for the plasma to flow into the details in the reaction chamber, and the carbon film remains in that portion. Therefore, the inventor of the present invention introduces only gas into the reaction chamber surface without forming plasma and causes it to wrap around to the details of the reaction chamber, and at that time, the introduced gas reacts with the carbon film and is blown into a gas state. As a result of diligent study, paying attention to good points, as a result of introducing a gas having a strong oxidizing power such as O ₂ , O ₃ , and H ₂ O into the reaction chamber for treatment, it is possible to circulate the gas into the details of the reaction chamber. It was possible, and at that time, it was possible to cause the carbon film to undergo an oxidation reaction to form a gas such as SiO ₂ and to fly it.

Therefore, not only the side wall of the reaction chamber but also the corners of the reaction chamber, the upper shower, the lower susceptor and the exhaust gas can be removed, and the carbon film in the reaction chamber can be removed almost completely. It was possible to obtain a carbon film of good film quality by suppressing the generation of particles during the film formation. Next, the present inventor first removes the carbon film in the reaction chamber by plasma treatment using O ₂ gas or the like. Since fine particle residual pickles such as carbon remain, it is necessary to coat the residual pickles so that they will not scatter during film formation. As a result of diligent study, plasma treatment with O ₂ gas or the like was performed. After that, when a chemically stable carbon film is coated in the reaction chamber by a film forming method or the like, it is possible to prevent the residual pickling that becomes particles during the subsequent carbon film formation on the wafer, which is good. It was possible to obtain a carbon film of various film quality.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic diagram showing the configuration of a plasma processing apparatus according to Embodiment 1 of the present invention. In this embodiment, R
The cleaning process after forming the F plasma CVD carbon film will be specifically described. In this embodiment, as shown in FIG. 1, the pressure inside the reaction chamber 1 is normal pressure, the inside of the reaction chamber 1 is heated to 100 ° C. or higher by the heater 3 provided below the susceptor 2, and O ₃ gas is supplied to the reaction chamber 1 Introduced into the interior of the reaction chamber 1
₃ gas can be circulated, and at that time, O
It was possible to oxidize the carbon film with ₃ gases to make it into a gaseous state such as SiO ₂ and blow it off and exhaust it.

For this reason, not only the side wall of the reaction chamber but also the corners of the reaction chamber, the upper part of the shower, the lower part of the susceptor and the exhaust part can be removed, and the carbon film in the reaction chamber can be removed almost completely. It was possible to obtain a carbon film of good film quality by suppressing the generation of particles during the film formation. In the above embodiment, the carbon film on the wafer is subjected to RF plasma CV.
The case of forming a film by the D method has been described, but the present invention is not limited to this, and the microwave plasma C
VD method, sputtering method, hot filament CVD method, DC discharge plasma CVD method, plasma jet CVD method or the like may be used.

In the above embodiment, O ₃ gas was used as the cleaning gas, but the present invention is not limited to this. In the present invention, O ₂ gas, O ₃ gas and H ₂ gas are used.
It suffices to use at least one type of O gas. Although the above-mentioned examples describe the preferred embodiment in which the carbon film is removed at atmospheric pressure in the reaction chamber where the gas concentration can be increased and the processing speed can be increased, the present invention is not limited to this and is performed under reduced pressure. May be. In addition, although the above-mentioned embodiment has described a preferable mode in which the inside of the reaction chamber 1 capable of activating the cleaning gas and the surface to be treated of the carbon film and the like is heat-treated, the present invention is not limited to this, and the temperature is not limited to room temperature. You may go in. (Embodiment 2) FIG. 2 is a schematic diagram showing the structure of a plasma processing apparatus according to Embodiment 2 of the present invention. In this embodiment, R
The process after forming the F plasma CVD carbon film will be described. In this embodiment, as shown in FIG. 2, the pressure in the reaction chamber 11 is set to 0.
5 Torr, and the electrode interval between the upper and lower electrodes is 2
0 mm and the frequency of the high frequency power supply 15 is 13.56 kHz
z was set, and O ₃ gas was introduced into the reaction chamber 11 and plasma treatment was performed to remove the carbon film in the reaction chamber 11. At this time, as described above, residual carbon film or fine particles such as carbon that cannot be completely removed remain in the reaction chamber 11 in detail, and then the reaction chamber 11 is coated with a carbon film by plasma CVD or the like. As a result, the residual pickling in the reaction chamber 11 could be coated with a chemically stable carbon film. For this reason, it is possible to prevent residual pickling that becomes particles during the subsequent film formation of the carbon film on the wafer, so that it is possible to obtain a carbon film of good film quality.

In the present invention, the plasma treatment and the coating treatment may be carried out individually. In this case, the plasma treatment and the coating treatment are carried out every time one wafer is formed. Because you can
This is preferable because the processing can be performed more efficiently than when the processing is performed after a number of wafers are continuously processed. In the above example,
The case where the carbon film is formed by the RF plasma CVD method has been described, but the present invention is not limited to this, and a microwave plasma CVD method, a sputtering method,
It may be performed by a hot filament CVD method, a DC discharge plasma CVD method, a plasma jet CVD method, or the like.

In the present embodiment, the case where the carbon film coating method capable of coating the wall surface of the reaction chamber 11 with good adhesion is performed by the plasma CVD method has been described, but the present invention is not limited thereto. Instead of the above method, the sputtering method or the like may be used. The above example
(Although O ₃ gas was used as the cleaning gas) In the present invention, at least one of O ₂ gas, O ₃ gas, N ₂ O gas, H ₂ O gas, H ₂ O ₂ gas and CO ₂ gas is used. You may use what consists of.

In the above embodiments, the case where the plasma treatment is performed once has been described, but in the present invention, the plasma treatment is performed at least twice or more by changing at least one of the pressure, the electrode interval and the frequency. In this case, as shown in FIG. 3, for example, the pressure is 0.05 Torr and the frequency is 13.56 kHz.
And set the electrode spacing to 1 with the pressure and frequency kept constant.
After plasma treatment to 0 mm, the electrode interval is 100 m
When the plasma treatment is performed at m, the carbon film on the upper portion of the susceptor 12 having the heater 13 and the exhaust portion can be efficiently etched. Further, as shown in FIG. 4, the pressure is set to 0.1 Torr and the electrode interval is 20 m.
When the plasma treatment is carried out at a frequency of 13.56 kHz after the plasma treatment is carried out at a frequency of 200 kHz in a state where the pressure is set to m and the electrode spacing is constant,
The carbon film on the side of the plasma reaction chamber 11 and the exhaust portion can be efficiently etched. Further, as shown in FIG. 5, the electrode interval is 20 mm and the frequency is 13.5.
When plasma treatment is performed at a pressure of 0.5 (2.0) Torr, for example, after performing plasma treatment at a pressure of 0.1 Torr in a state where the electrode interval and frequency are constant at 6 kHz, a shower is generated. 14 Upper part and susceptor 1
2 The carbon film on the upper part can be efficiently etched. When the plasma treatment is performed by appropriately combining the appropriate values of the electrode spacing, the pressure and the frequency, the carbon film can be efficiently etched.

[0023]

According to the present invention, not only the side wall of the reaction chamber but also the corners of the reaction chamber, the upper portion of the shower, the lower portion of the susceptor, and the exhaust portion are removed, and the carbon film in the reaction chamber is almost completely removed. It is possible to suppress the generation of particles during the subsequent film formation, and it is possible to obtain a carbon film having a good film quality.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram showing a configuration of a plasma processing apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram showing an etching rate of a carbon film with respect to an electrode interval at each position in a reaction chamber according to Example 2 of the present invention.

FIG. 4 is a diagram showing an etching rate of a carbon film with respect to a frequency at each position in a reaction chamber according to Example 2 of the present invention.

FIG. 5 is a diagram showing an etching rate of a carbon film with respect to pressure at each position in a reaction chamber according to Example 2 of the present invention.

FIG. 6 is a diagram showing a problem of a conventional example.

[Explanation of symbols]

 1, 11 Reaction chamber 2, 12 Susceptor 3, 13 Heater 14 Shower 15 High frequency power supply 101 Reaction chamber 102 Shower 103 Heater 104 Susceptor 105 RF power supply

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoji Okuda 1844-2, Kozoji-cho, Kasugai-shi, Aichi Prefecture, Fujitsu Limited, Vier SII Co., Ltd. Address within Fujitsu Limited (72) Inventor Hideaki Kikuchi 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Within Fujitsu Limited

Claims (10)

[Claims] 1. A method of manufacturing a semiconductor device, which comprises a step of removing a carbon film deposited in a reaction chamber by a film forming method by an oxidizing reaction with a gas for oxidizing the carbon film. 2. The gas for oxidizing the carbon film is O ₂
The method of manufacturing a semiconductor device according to claim 1, wherein the method comprises at least one of gas, O ₃ gas, and H ₂ O gas. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the removal of the carbon film is performed under a normal pressure in the reaction chamber. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the carbon film is removed by heating the reaction chamber. 5. A step of removing a carbon film deposited in the reaction chamber by a film forming method by plasma treatment using a gas containing at least oxygen atoms, and a step of coating the reaction chamber with the carbon film. A method of manufacturing a semiconductor device, comprising: 6. The method of manufacturing a semiconductor device according to claim 5, wherein the plasma treatment and the coating treatment are performed individually. 7. The gas containing at least oxygen atoms is O ₂ gas, O ₃ gas, N ₂ O gas, H ₂ O gas, H _2.
7. The method for manufacturing a semiconductor device according to claim 5, wherein the method comprises at least one of ₂ O ₂ gas and CO ₂ gas. 8. The pressure during the plasma treatment is 0.01T.
8. The method for manufacturing a semiconductor device according to claim 5, wherein it is not less than orr and not more than 2.0 Torr. 9. The method of manufacturing a semiconductor device according to claim 5, wherein an electrode interval between the upper electrode and the lower electrode during the plasma processing is 10 mm or more and 100 mm or less. 10. The plasma treatment is performed by changing at least one of pressure, electrode spacing, and frequency to produce at least 2.
10. The method of manufacturing a semiconductor device according to claim 5, wherein the treatment is performed more than once.