JPH05275353A - Plasma processor and method of cleaning that device - Google Patents

Abstract

PURPOSE:To provide a plasma processor which can generate plasma concentrically at or around an insulation preventive plate and can efficiently remove the products adhering to the above-mentioned insulation preventive plate. CONSTITUTION:In a plasma processor, wherein a susceptor 16 is arranged in the plasma processing chamber 10, an insulation preventive plate 19 is arranged at or around the inwall 17 of the plasma processing chamber, and an electrode 15 for application of high frequency is interposed between the insulation preventive plate 19 and the inwall 17 of the plasma processing chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a cleaning method for the apparatus, and more particularly, a sample stage is provided in a plasma processing chamber for forming a CVD thin film on the sample by plasma processing. The present invention relates to a plasma processing apparatus and a cleaning method for the apparatus.

[0002]

2. Description of the Related Art In the manufacture of large scale integrated circuits, it is necessary to deposit a thin film on a semiconductor wafer to form a fine pattern. At the time of forming the thin film, the thin film formed product adheres to a place other than the sample, and the thin film formed product peels off to become particles, and the particles may adhere to the sample to cause a short circuit of the wiring. For this reason, the removal of deposits that cause defective samples is emphasized.

FIG. 3 is a sectional view schematically showing an example of a conventional plasma processing apparatus, and 30 in the drawing shows a processing chamber. An upper electrode 35 is provided above the processing chamber 30, and an insulator 34a is provided above the upper electrode 35. The upper electrode 35 is connected to a changeover switch 38a, and is connected to the high frequency power source 32a or the ground 33a via the changeover switch 38a. Further, the processing chamber 3 is opposed to the upper electrode 35.
A lower electrode 36 is disposed below 0. The sample 31 is placed on the upper surface of the lower electrode 36.
An insulator 34b is disposed below the element 6. This lower electrode 36 is connected to a changeover switch 38b,
It is adapted to be connected to the high frequency power source 32b or the earth 33b via the changeover switch 38b. The ground 33c is also connected to the side wall 37 forming the processing chamber 30.

When performing plasma processing using the plasma processing apparatus having such a configuration, first, a high frequency voltage is supplied to the lower electrode 36 side via the changeover switch 38b, and the upper electrode 35 is grounded via the changeover switch 38a. By connecting to 33a and supplying the raw material gas from a gas inlet (not shown), the supplied raw material gas is made into plasma and the sample 31 is subjected to plasma treatment. At this time, the product adheres to a place other than the sample 31, and if the adhered film peels off, it causes particles. Therefore, it becomes necessary to clean the adhered substance. At the time of cleaning this deposit, a high-frequency voltage is supplied to the upper electrode 35 via the changeover switch 38a, while the lower electrode 36 is kept connected to the high-frequency power source 32b on the lower electrode 36 side to discharge between the electrodes 35, 36. The discharge impedance between the upper electrode 35 and the inner wall of the processing chamber 30 is controlled to be lower than the impedance. As a result, the plasma spreads to the inner wall of the processing chamber 30 and the back surface of the upper electrode 35,
It is possible to remove the deposits attached to such places.

[0005]

When the plasma processing apparatus described above is used to clean the apparatus, plasma generated is concentrated near the upper electrode 35 and the lower electrode 36. However, the place where the adhered substance needs to be removed is the side wall 37 or the like of the processing chamber 30, and even if a high frequency voltage is applied to the upper electrode 35, the plasma cannot be concentrated on the side wall 37 and the side wall 37 and the like. There is a problem that it takes a long time to remove the deposits attached to the.

The present invention has been made in view of the above-mentioned problems, and plasma can be concentrated and distributed in a place where it is necessary to remove deposits, and deposits can be efficiently removed by plasma. It is an object of the present invention to provide a possible plasma processing apparatus and a cleaning method for the apparatus.

[0007]

In order to achieve the above-mentioned object, a plasma processing apparatus and a method for cleaning the same according to the present invention are provided with a sample stage in a plasma processing chamber,
In a plasma processing apparatus for processing a sample with plasma, a deposition preventive plate formed of an insulator is disposed near the inner wall of the plasma processing chamber to prevent reaction products from adhering to the inner wall of the plasma processing chamber, A high-frequency applying electrode is interposed between the insulation-preventing plate and the inner wall of the plasma processing chamber, and the plasma processing apparatus cleaning method according to the present invention is provided for etching the plasma processing chamber. It is characterized in that a high-frequency power is supplied to the high-frequency applying electrode as well as the gas is supplied to remove the deposits adhering to the deposition preventive plate by etching.

[0008]

According to the apparatus described above, in the plasma processing apparatus in which the sample stage is arranged in the plasma processing chamber, the deposition preventive plate made of an insulating material is arranged near the inner wall of the plasma processing chamber, Since a high-frequency applying electrode is interposed between the deposition plate and the plasma processing chamber inner wall, by applying a high frequency to the high-frequency applying electrode during cleaning, plasma is concentrated only in the vicinity of the insulation-prevention plate. As a result, the reaction products attached to the insulating and deposition preventing plate can be efficiently removed.

According to the cleaning method of the plasma processing apparatus of the present invention, the above apparatus is used to supply the etching gas to the plasma processing chamber, apply the high frequency to the high frequency applying electrode, and adhere to the insulating / adhesive plate. Since the adhered substances are removed by etching, plasma is generated in the vicinity of the insulating / adhesion-preventing plate by the high-frequency application to the high-frequency applying electrode, and the concentrated plasma adheres to the adhesion-preventing plate. It is possible to efficiently remove the reaction product.

[0010]

EXAMPLES AND COMPARATIVE EXAMPLES Examples of a plasma processing apparatus and a cleaning method for the apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a plasma processing apparatus according to an embodiment, and 13 in the drawing denotes a plasma generation chamber. A microwave introduction port 18 is formed at a substantially central portion of the left end portion of the plasma generation chamber 13, and a gas introduction port 18 a is formed below the microwave introduction port 18. Around the plasma generation chamber 13, the plasma generation chamber 1
An exciting coil 14 is arranged substantially concentrically with No. 3.

On the right side of the plasma generation chamber 13, there is formed a plasma processing chamber 10 which communicates with the plasma generation chamber 13 through a plasma drawing window 13a.

A sample table 16 for holding the sample 11 by an electrostatic chuck or the like is provided at a position facing the plasma extraction window 13a on the right side of the plasma processing chamber 10. Inside the inner wall 17 of the plasma processing chamber 10, an electrode 15 for high frequency application, which is electrically insulated and is formed of Ti as a material, is arranged, and the inside of the electrode 15 has a small thermal expansion coefficient. An insulating / adhesion-preventing plate 19 made of a material such as quartz is provided. A high frequency power source 12 is connected to the electrode 15. The gap between the electrode 15 and the inner wall 17 is set to be sufficiently small so that plasma is not generated between the electrode 15 and the inner wall 17 even if a high frequency is applied to the electrode 15, and the inner wall 17 serves as a high frequency shield for the electrode 15. Is configured to fulfill.

Using the thus-configured plasma processing apparatus, for example, O ₂ gas and SiH ₄ gas were supplied to the sample 11
When depositing SiO ₂ film on, the SiO ₂ film adheres to the inner circumferential surface of the insulating deposition preventing plate 19. When cleaning this SiO ₂ film, the inside of the plasma generation chamber 13 and the plasma processing chamber 10 is set to a required degree of vacuum, and then the etching gas C is introduced into the plasma generation chamber 13 through the gas inlet port 18a.
Supply F ₄ . Then, a direct current is passed through the exciting coil 14 and at the same time, a microwave is guided to the plasma generation chamber 13 to generate plasma in the plasma generation chamber 13. A rightward magnetic field is uniformly formed over almost the entire area of the plasma generation chamber 13 by the flow to the exciting coil 14, and the plasma is guided into the plasma processing chamber 10 by this divergent magnetic field. In addition, the electrode 15 is also 400K by the high frequency power source 12.
A high frequency of H _Z is applied.

When the microwave is introduced into the plasma generation chamber 13 while forming the magnetic field in this way, the gas is resonantly excited by using the plasma generation chamber 13 as a cavity resonator, and the plasma generation chamber 13 is efficiently evacuated in a wide region. Plasma is generated. The 10 by the high frequency power source 12 of the 400KH _Z
When a high frequency power of 0 W is applied to the electrode 15, plasma is concentrated near the insulating / adhesive plate 19, and the SiO ₂ film attached to the insulating / adhesive plate 19 can be efficiently removed. In addition,
The gap between the electrode 15 and the insulation-preventing plate 19 is made as small as possible, and the inner wall 17 plays a role of a high frequency shield against the electrode 15, so that plasma is generated between the inner wall 17 and the electrode 15. There is no.

Table 1 shows the results when the cleaning conditions were changed using the above apparatus.

[0017]

[Table 1]

No. 1 does not apply high frequency to the electrode 15,
The etching rate in the insulating and deposition preventing plate 19 when a microwave is introduced into the plasma generation chamber 13 and a direct current is passed through the exciting coil 14 is shown. No. 2 shows the etching rate in the insulating and deposition preventing plate 19 when a high frequency is applied to the electrode 15 and no microwave is introduced into the plasma generation chamber 13. Reference numeral 3 denotes an etching rate in the insulation-preventing plate 19 when a current is passed through the exciting coil 14, a microwave is introduced into the plasma generation chamber 13, and a high frequency voltage is also applied to the electrode 15.

As is clear from Table 1, when high frequency is not applied to the electrode 15, almost no deposits are removed, and when the high frequency voltage is only applied to the electrode 15, etching of the insulating / adhesive plate 19 is performed. Than rate
At the same time when a high frequency voltage is applied to the electrode 15, a current is passed through the exciting coil 14 and a microwave is introduced into the plasma generation chamber 13, the etching rate with respect to the insulation-prevention plate 19 is remarkably high. As described above, it has been clarified that by applying the microwave power and the high frequency power to the electrode 15, it is possible to very efficiently remove the deposits on the insulating and deposition preventing plate 19.

Further, as described above, the insulating and deposition preventing plate is arranged,
The method of applying a high frequency voltage to the electrodes to remove the deposits is not limited to the above ECR plasma CVD apparatus, and as shown in FIG. 2, it can be similarly performed in a parallel plate type plasma processing apparatus. it can.

FIG. 2 is a sectional view schematically showing an embodiment of a parallel plate type plasma processing apparatus, and 20 in the drawing shows a plasma processing chamber. An upper electrode 25 is provided above the plasma processing chamber 20, and an insulator 24 a is provided above the upper electrode 25. The upper electrode 25 is connected to the earth 23a. Further, a lower electrode 26 is arranged below the plasma processing chamber 20 so as to face the upper electrode 25. The sample 21 is placed on the upper surface of the lower electrode 26, and the insulator 24 b is disposed below the lower electrode 26. The lower electrode 26 is a high frequency power source 22a.
It is connected to the. In addition, the inner wall 27 of the plasma processing chamber 20
An electrode 45 made of Ti is disposed near the
Further, inside the electrode 45, an insulating / adhesive plate 29 made of quartz or the like, which is a material having a small thermal expansion coefficient, is arranged. The electrode 45 is connected to the high frequency power source 22b.

At the time of cleaning the thus-configured plasma processing apparatus, by supplying high-frequency power from the high-frequency power source 22b connected to the electrode 45 to generate high-frequency plasma only in the vicinity of the insulation-prevention plate 29, The reaction product attached to the insulation-preventing plate 29 can be efficiently removed. It should be noted that, as in the case of the above embodiment, the electrode 45
The gap between the inner wall 27 and the inner wall 27 is made as small as possible, and the inner wall 27 plays a role of a high frequency shield with respect to the electrode 45.

In the case of the parallel plate type plasma apparatus shown in FIG. 2, it is possible to obtain the same etching rate as in the case where only the high frequency is applied to the electrode 15 in the embodiment shown in FIG.

[0024]

As is clear from the above description, in the plasma processing apparatus according to the present invention, the reaction table is provided with the sample stage in the plasma processing chamber and the reaction product Is attached to the inner wall of the plasma processing chamber, an adhesion preventive plate made of an insulating material is disposed in the vicinity of the plasma processing chamber inner wall, and the insulating and deposition preventing plate and the plasma processing chamber inner wall are provided between the insulating and deposition preventing plate and the plasma processing chamber inner wall. Since an electrode for high-frequency application is provided, during cleaning, an etching gas is supplied to the plasma processing chamber to generate plasma, and when the plasma removes the deposits adhering to the deposition preventive plate, By applying a high frequency to the application electrode, it is possible to concentrate the plasma in the vicinity of the deposition-inhibitory plate, and this concentration of plasma prevents the reaction products attached to the deposition-inhibitory plate from being removed. It can be efficiently removed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a plasma processing apparatus according to the present invention.

FIG. 2 is a sectional view schematically showing another embodiment of the plasma processing apparatus according to the present invention.

FIG. 3 is a sectional view schematically showing an example of a conventional plasma processing apparatus.

[Explanation of symbols]

 10, 20 Plasma processing chamber 15, 45 Electrode 16 Sample stage 17, 27 Inner wall 19, 29 Insulation-proof plate

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Satoshi Tanihara 1-3-3 Otemachi, Chiyoda-ku, Tokyo Sumitomo Metal Industries, Ltd.

Claims (2)

[Claims] 1. In a plasma processing apparatus in which a sample stage is disposed in a plasma processing chamber and a sample is processed by plasma, the plasma processing chamber inner wall is provided to prevent reaction products from adhering to the inner wall of the plasma processing chamber. A plasma processing apparatus, wherein an adhesion preventing plate formed of an insulator is disposed in the vicinity, and a high frequency applying electrode is interposed between the adhesion preventing plate and the inner wall of the plasma processing chamber. 2. The apparatus according to claim 1, wherein an etching gas is supplied to the plasma processing chamber, and high-frequency power is supplied to the high-frequency applying electrode to etch and remove deposits adhering to the deposition preventive plate. A method for cleaning a plasma processing apparatus, comprising: