KR100891754B1 - Method for cleaning substrate processing chamber, storage medium and substrate processing chamber - Google Patents

Abstract

The present invention provides a method for cleaning a substrate processing chamber that can prevent formation of an oxide film on the surface of a component in the processing chamber.

In the present invention, in the plasma processing apparatus 10 having the reaction product attached to the surface of the upper electrode plate 38, after the wafer W is carried out from the substrate processing chamber 11, oxygen gas is introduced into the processing space S, The pressure of the processing space S is set to 26.7 kPa to 80.0 kPa, the electrode plate surface-space potential difference is set to 0 eV, the size of the high frequency power of 40 MHz is set to 500 W or less, and the plasma is generated by the 40 MHz high frequency power. Dry cleaning processing is carried out, and tetrafluorocarbon gas is introduced into the processing space S, and plasma is generated by high frequency power of 40 MHz and 2 MHz to perform an oxide removal process.

Description

METHODE FOR CLEANING SUBSTRATE PROCESSING CHAMBER, STORAGE MEDIUM AND SUBSTRATE PROCESSING CHAMBER}

1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus to which a cleaning method of a substrate processing chamber according to each embodiment of the present invention is applied;

2 is a graph showing a change in the ratio of oxygen radicals to argon radicals in the plasma when the pressure in the processing space is changed;

3 is a graph showing the number of oxygen ions per unit time reaching the side wall member when the pressure in the processing space is changed;

4 is a diagram showing a change in sputtering rate by argon radicals when the potential difference is changed;

5 is a view showing a collision between oxygen ions and the upper electrode plate,

5 (a) is a diagram showing a case where an electrode plate surface-space potential difference is zero;

5B is a view showing a case where the electrode plate surface-space potential difference is about 100 eV;

5 (c) is a diagram showing a case where the electrode plate surface-space potential difference is 150 eV or more,

6 is a flowchart of the cleaning method of the substrate processing chamber according to the first embodiment of the present invention;

7 is a flowchart of the cleaning method of the substrate processing chamber according to the second embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

S: processing space W: wafer

10 plasma processing apparatus 11 substrate processing chamber

12: susceptor 20: high frequency power

34 gas introduction shower head 38 upper electrode plate

46: other high frequency power 49: DC power

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a substrate processing chamber, a storage medium and a substrate processing chamber, and more particularly, to a method for cleaning a substrate processing chamber including an electrode made of silicon.

BACKGROUND OF THE INVENTION A plasma processing apparatus is known that includes a substrate processing chamber having a processing space into which a semiconductor wafer as a substrate is loaded, and a lower electrode disposed in the processing space and connected to a high frequency power source. In this plasma processing apparatus, a processing gas is introduced into the processing space, and the lower electrode applies high frequency power to the processing space. In addition, when the semiconductor wafer is loaded into the processing space and mounted on the lower electrode, ions and the like are generated using the introduced processing gas as plasma by high frequency power, and plasma processing, for example, etching processing is performed on the semiconductor wafer. Conduct.

In the above-described plasma processing apparatus, a storage gas is used as a processing gas, for example, C ₄ F _8. When a mixed gas such as gas and argon (Ar) gas is used, the reaction product generated from the reaction gas adheres to the inner surface of the substrate processing chamber, for example, the side inner wall (hereinafter simply referred to as "side wall"). The attached reaction product is peeled off from the sidewalls into particles. Particles adhere to semiconductor wafers and cause defects in semiconductor devices manufactured from the semiconductor wafers. Therefore, it is necessary to remove the reaction product adhering to the inner surface of the substrate processing chamber.

Conventionally, as a method for removing a reaction product adhered to the inner surface, oxygen (O ₂ ) gas is introduced into a processing space, and oxygen ions or oxygen radicals are generated from oxygen gas by high frequency electric power, and the reaction product is oxygen ions. And a method of reacting and removing with an oxygen radical are known (see Patent Document 1, for example).

(Patent Document 1) Japanese Unexamined Patent Publication No. 62-40728

By the way, in recent years, for the purpose of improving plasma processing performance, an upper electrode serving as a component in a processing chamber, which is disposed to face the lower electrode in a processing space, is made of silicon, and a plasma processing in which a direct current power source is connected to the upper electrode. The device is developed. In this plasma processing apparatus, when the above-described reaction product removal method is executed, the reaction product adhered to the inner surface of the substrate processing chamber is certainly removed, but oxygen ions, oxygen radicals, and silicon of the upper electrode react to form silicon oxide (SiO). Oxides such as ₂ ) are generated. The oxide may adhere to the surface of the electrode to form an oxide film. The oxide film is also peeled off to form particles. In addition, since the direct current cannot penetrate the oxide film, it becomes difficult to apply the direct current voltage to the processing space. In addition, since the oxide film may be dielectrically broken by the direct current, it is difficult to stabilize the state of the plasma in the processing space.

An object of the present invention is to provide a method for cleaning a substrate processing chamber, a storage medium and a substrate processing chamber which can prevent the formation of an oxide film on the surface of a component in the processing chamber.

In order to achieve the above object, the cleaning method of the substrate processing chamber according to the first aspect is a substrate processing chamber having a space into which a substrate is loaded, and performing plasma processing on the substrate in the space, wherein at least a portion of the substrate processing chamber is exposed to the space. And a method of cleaning a substrate processing chamber including at least a component in a processing chamber containing silicon, the method comprising: a first plasma treatment for performing a deposit removal treatment on a component in the processing chamber by a first plasma generated from oxygen gas introduced into the space; And a second plasma treatment step of performing an oxide removal treatment on the components in the processing chamber by a second plasma generated from the tetrafluorocarbon gas introduced into the space.

The cleaning method of the substrate processing chamber according to the second aspect is the cleaning method of the substrate processing chamber according to the first aspect, wherein the component in the processing chamber is an electrode disposed opposite to the substrate loaded into the space and connected to a DC power source. It features.

The cleaning method of the substrate processing chamber according to the third aspect is the cleaning method of the substrate processing chamber according to the first aspect, wherein the pressure in the space in the first plasma processing step is set to 26.7 kPa to 80.0 kPa. .

The cleaning method of the substrate processing chamber according to the fourth aspect is the cleaning method of the substrate processing chamber according to the first aspect, wherein the frequency in which the ions in the first plasma are applied to the space in the first plasma processing step can be followed. The difference between the potential generated on the surface of the component in the processing chamber and the potential in the space due to the high frequency power of is set to 150 eV or more.

The cleaning method of the substrate processing chamber according to the fifth aspect is the cleaning method of the substrate processing chamber according to the first aspect, wherein the frequency in which the ions in the first plasma are applied to the space in the first plasma processing step can be followed. The high frequency power of is characterized in that it is set to 0W.

In the cleaning method of the substrate processing chamber according to the sixth aspect, in the cleaning method of the substrate processing chamber according to the first aspect, the frequency in which the ions in the first plasma are applied to the space in the first plasma processing step cannot be followed. The high frequency power of is characterized in that it is set to 500W or less.

In order to achieve the above object, the storage medium according to the seventh aspect has a space into which a substrate is loaded, and is a substrate processing chamber in which a plasma processing is performed on the substrate in the space, at least part of which is exposed to the space, A computer-readable storage medium for storing a program for causing a computer to execute a method for cleaning a substrate processing chamber having components in a processing chamber including at least silicon, the program being stored in a first plasma generated from oxygen gas introduced into the space. By means of a first plasma processing module for performing deposit removal treatment on the components in the processing chamber and a second plasma for performing oxide removal treatment on the components in the processing chamber by a second plasma generated from the tetrafluorocarbon gas introduced into the space. It is characterized by having a processing module.

In order to achieve the above object, the substrate processing chamber according to the eighth aspect has a space into which a substrate is loaded, and is a substrate processing chamber which performs plasma processing on the substrate in the space, at least part of which is exposed to the space, and at least A substrate processing chamber having components in a processing chamber containing silicon, comprising: a gas introduction device for introducing a predetermined gas into the space; an electrode for applying a high frequency power to the space into which the gas is introduced to generate plasma; When oxygen gas is introduced into the space, the electrode applies a high frequency power to the space to generate a first plasma, when the first plasma is removed from the space and tetrafluorocarbon gas is introduced into the space, The electrode is characterized by generating a second plasma by applying a high frequency power to the space.

Best Mode for Carrying Out the Invention Embodiments of the present invention will be described below with reference to the drawings.

First, the plasma processing apparatus to which the cleaning method of the substrate processing chamber which concerns on each Example of this invention mentioned later is applied is demonstrated.

1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus to which a cleaning method of a substrate processing chamber according to an embodiment of the present invention is applied. This plasma processing apparatus is configured to perform a reactive ion etching (RIE) process or an ashing process on a semiconductor wafer W serving as a substrate.

In FIG. 1, the plasma processing apparatus 10 has a cylindrical substrate processing chamber 11, and the substrate processing chamber 11 has a processing space S therein. In the substrate processing chamber 11, for example, a cylindrical susceptor 12 serving as a mounting table on which a semiconductor wafer W having a diameter of 300 mm (hereinafter referred to simply as "wafer W") is placed is disposed. The inner wall surface of the substrate processing chamber 11 is covered with the side wall member 45. The side wall member 45 is made of aluminum, and the surface facing the processing space S is coated with yttria (Y ₂ O ₃ ). The wall of the substrate processing chamber 11 is electrically grounded, and the susceptor 12 is provided at the bottom of the substrate processing chamber 11 via the insulating member 29. The side of the susceptor 12 is covered with a susceptor side covering member 60.

In the plasma processing apparatus 10, the inner wall of the substrate processing chamber 11 and the side surface of the susceptor 12 function as a flow path for discharging gas molecules above the susceptor 12 out of the substrate processing chamber 11. An exhaust path 13 is formed. An annular baffle plate 14 is disposed in the middle of the exhaust passage 13 to prevent plasma leakage. In addition, the space downstream from the baffle plate 14 in the exhaust path 13 returns to the lower side of the susceptor 12, and is an automatic pressure control valve (hereinafter, referred to as a variable butterfly valve). Communication with the " APC valve " The APC valve 15 is connected to a turbo molecular pump (hereinafter referred to as "TMP") 17 which is an exhaust pump for vacuum suction through an isolator 16, and the TMP 17 is It is connected to the dry pump (henceforth "DP") 18 which is an exhaust pump via valve V1. The exhaust flow path constituted by the APC valve 15, the isolator 16, the TMP 17, the valve V1, and the DP 18 is more specifically provided in the substrate processing chamber 11 by the APC valve 15. The pressure control of the processing space S is performed, and the pressure is reduced until the inside of the substrate processing chamber 11 is almost vacuumed by the TMP 17 and the DP 18.

In addition, a pipe 19 is connected to the DP 18 via the valve V2 between the isolator 16 and the APC valve 15. The piping 19 and the valve V2 bypass the TMP 17 and roughly pump the inside of the substrate processing chamber 11 by the DP 18.

A high frequency power source 20 is connected to the susceptor 12 via a feed rod 21 and a matcher 22, and the high frequency power source 20 is a high frequency power of a relatively high frequency, for example, 40 MHz. To the susceptor 12. Accordingly, the susceptor 12 functions as a lower electrode. In addition, the matcher 22 reduces the reflection of the high frequency power from the susceptor 12 to maximize the supply efficiency of the high frequency power to the susceptor 12. The susceptor 12 applies 40 MHz high frequency power supplied from the high frequency power supply 20 to the processing space S. FIG.

In addition, another high frequency power source 46 is connected to the susceptor 12 via a feed rod 35 and a matching unit 36, and the other high frequency power source 46 has a relatively low frequency, for example, 2 MHz. High frequency power is supplied to the susceptor 12. The matcher 36 has the same function as the matcher 22. The susceptor 12 applies the high frequency power of 2 MHz supplied from the other high frequency power supply 46 to the processing space S. FIG. At this time, the surface of the side wall member 45 facing the processing space S, the susceptor side covering member 60 and the upper electrode plate 38 described later is caused by the high frequency power of 2 MHz applied to the processing space S. Potential potential occurs. The frequency of the potential potential is 2 MHz. Accordingly, the difference between the potential potential generated on the surface of the upper electrode plate 38 and the like and the potential of the processing space S (hereinafter, simply referred to as the "electrode plate surface-space potential difference") also fluctuates to 2 MHz. It is known that cations such as argon ions (Ar +) having an electron density (Ne) of 10 ¹⁰ cm ^-3 can follow variations in potential differences up to about 3.3 MHz. That is, since the cations can follow the variation of the electrode plate surface-space potential difference, a number of cations in accordance with the electrode plate surface-space potential difference collide with the surface of the upper electrode plate 38 or the like. Specifically, when the electrode plate surface-space potential difference is large, many cations collide with the surface of the upper electrode plate 38 or the like, and when the electrode plate surface-space potential difference is 0eV, the cation is the upper electrode plate 38 or the like. Hardly hits its surface. Moreover, since the high frequency electric power supplied from the high frequency power supply 20 to the susceptor 12 is 40 MHz, when a potential electric potential generate | occur | produces on the surface of the upper electrode plate 38 due to the high frequency electric power, this potential electric potential and a process will be processed. The difference with the potential of the space S varies at 40 MHz. However, since the cations cannot follow the potential difference which fluctuates at 40 MHz, the cations substantially follow the direct current component of the high frequency power which fluctuates at 40 MHz, and the electrodes act on the cations due to the high frequency power fluctuating at 40 MHz. The plate surface-space potential difference is about half of the electrode plate surface-space potential difference acting on the cation due to the high frequency power fluctuating at 2 MHz. Therefore, it is not effective to control the number of cations that collide with the surface of the upper electrode plate 38 or the like by the high frequency power fluctuating at 40 MHz.

Above the inside of the susceptor 12, a disk shaped ESC electrode plate 23 made of a conductive film is disposed. The ESC DC power supply 24 is electrically connected to the ESC electrode plate 23. The wafer W is adsorbed and held on the upper surface of the susceptor 12 by the Coulomb force or Johnsen-Rahbek force generated by the DC voltage applied from the ESC DC power supply 24 to the ESC electrode plate 23. . In addition, above the susceptor 12, a round ring-shaped focus ring 25 is disposed to surround the wafer W adsorbed and held on the upper surface of the susceptor 12. The focus ring 25 is exposed to the processing space S, and the plasma is converged toward the surface of the wafer W in the processing space S to improve the efficiency of the RIE process or the ashing process.

In the susceptor 12, an annular refrigerant chamber 26 extending in the circumferential direction is provided, for example. The refrigerant chamber 26 is circulated and supplied from a chiller unit (not shown) to the refrigerant at a predetermined temperature such as cooling water or Galden (registered trademark) liquid through a refrigerant pipe 27. The processing temperature of the wafer W adsorbed and held on the susceptor 12 upper surface is controlled by the temperature of the refrigerant.

In addition, a plurality of heat transfer gas supply holes 28 are opened in a portion where the wafer W on the upper surface of the susceptor 12 is adsorbed and held (hereinafter, referred to as a "adsorption surface"). These peripheral heat transfer gas supply holes 28 are connected to the heat transfer gas supply part 32 via the heat transfer gas supply line 30 arrange | positioned inside the susceptor 12, The heat transfer gas supply part 32 is a heat transfer gas. Helium gas is supplied to the gap between the suction surface and the wafer W surface via the electrothermal gas supply hole 28.

In addition, on the suction surface of the susceptor 12, a plurality of pusher pins 33 are provided as lift pins protruding from the upper surface of the susceptor 12. These pusher pins 33 are connected via a motor (not shown) and a ball screw (not shown), and freely protrude from the suction surface due to the rotational motion of the motor converted into linear motion by the ball screw. When the wafer W is adsorbed and held on the adsorption surface in order to perform the RIE process or the ashing process on the wafer W, the pusher pin 33 is accommodated in the susceptor 12 and the wafer W subjected to the RIE process or the ashing process is subjected to the substrate processing chamber. When carrying out from (11), the pusher pin 33 protrudes from the upper surface of the susceptor 12, separates the wafer W from the susceptor 12, and lifts it upwards.

In the ceiling of the substrate processing chamber 11, a gas introduction shower head 34 (gas introduction device) is disposed to face the susceptor 12. The gas introduction shower head 34 includes an electrode plate support 39 made of an insulating material having a buffer chamber 40 formed therein, and an upper electrode plate 38 (part in the processing chamber) supported by the electrode plate support 39. ). The upper electrode plate 38 is exposed to the processing space S at its lower surface (surface). In addition, the upper electrode plate 38 is a conductive material, for example. It is a disk-shaped member made of silicon. The periphery of the upper electrode plate 38 is covered by an annular insulating member 47 made of an insulating material. That is, the upper electrode plate 38 is electrically insulated from the wall portion of the substrate processing chamber 11 at the ground potential by the electrode plate support 39 and the insulating member 47.

The process gas introduction pipe 41 from a process gas supply part (not shown) is connected to the buffer chamber 40 of the electrode plate support body 39. A pipe insulator 42 is disposed in the middle of the process gas introduction pipe 41. In addition, the gas introduction shower head 34 has a plurality of gas holes 37 for conducting the buffer chamber 40 to the processing space S. FIG. The gas introduction shower head 34 supplies the processing gas supplied from the processing gas introduction pipe 41 to the buffer chamber 40 to the processing space S via the gas hole 37.

The upper electrode plate 38 is electrically connected to the DC power supply 49, and a negative DC voltage is applied to the upper electrode plate 38. In this case, since there is no need to arrange a matching device between the upper electrode plate 38 and the DC power supply 49, the plasma processing apparatus 10 of the plasma processing apparatus 10 can be compared with the case where a high frequency power supply is connected to the upper electrode plate through the matching device. The structure can be simplified. In addition, since the upper electrode plate 38 does not fluctuate as it is in the negative potential, it can be maintained in the state where only cation is drawn in, and electrons are not lost from the processing space S. Therefore, electrons do not decrease in the processing space S, and as a result, the efficiency of plasma processing such as RIE processing and ashing processing can be improved.

In addition, the sidewalls of the substrate processing chamber 11 are provided with a wafer W carrying in / out 43 at a position corresponding to the height of the wafer W lifted upward from the susceptor 12 by the pusher pins 33. A gate valve 44 that opens and closes the carrying in and out 43 is attached to the carrying in and out 43.

In the substrate processing chamber 11 of the plasma processing apparatus 10, as described above, the susceptor 12 applies high frequency power to the processing space S which is a space between the susceptor 12 and the upper electrode plate 38. In this process space, the processing gas supplied from the gas introduction shower head 34 is a high density plasma to generate cations and radicals in the processing space S, and the RIE treatment and ashing treatment are performed on the wafer W by the cations and radicals. Conduct.

In addition, the operation of each component of the plasma processing apparatus 10 described above is controlled by a CPU of a controller (not shown) included in the plasma processing apparatus 10 in accordance with a program corresponding to an RIE process or an ashing process.

In the plasma processing apparatus 10 described above, the RIE process is performed on the wafer W. At this time, when a storage gas, for example, a mixed gas of C ₄ F ₈ gas and argon gas is used, the reaction generated from the reaction gas is performed. The product is attached to the surface of the upper electrode plate 38, the surface of the side wall member 45, and the surface of the susceptor side covering member 60. In order to remove the reaction product adhering to the surface of each part, a dry cleaning process described in detail below is performed.

In the dry cleaning process, oxygen gas is introduced into the processing space S from the gas introduction shower head 34, and high frequency powers of 40 MHz and 2 MHz are applied to the processing space S into which the oxygen gas is introduced by the susceptor 12. do. In the processing space S, oxygen ions and oxygen radicals are mainly generated from oxygen gas by high frequency power of 40 MHz. This oxygen ion or oxygen radical reacts with the reaction product to remove the reaction product.

By the way, when the dry cleaning process is performed in the plasma processing apparatus 10, an oxide film made of silicon oxide is formed on the surface of the upper electrode plate 38 made of silicon as described above. The surface of the upper electrode plate 38 on which the oxide film is formed is whitishly blurred. Prior to the present invention, the inventors have carried out the conditions for performing dry cleaning processing, for example, the pressure in the processing space S, the 40 MHz applied to the processing space S, in order to examine the conditions capable of suppressing the formation of the oxide film in the dry cleaning processing. Formation state of the oxide film on the surface of the upper electrode plate 38 when the magnitude (power) of the high frequency electric power and the electrode plate surface-space potential difference (indicated by "potential difference between the processing space and the upper electrode plate" in Table 3) are changed. Was observed, and the observation results shown in the following Tables 1 to 3 were obtained.

That is, when the pressure in the processing space S is high, the oxide film is less likely to be formed, and the smaller the size of the high frequency power of 40 MHz applied to the processing space S, the more difficult the oxide film is to be formed. Knowledge was found to be difficult to form. Specifically, if the pressure in the processing space S is 26.7 Pa (200 mTorr) or more, no oxide film is formed on the surface of the upper electrode plate 38, and if the size of the 40 MHz high frequency power applied to the processing space S is 500 W or less, It was found that no oxide film was formed on the copper surface, and that no oxide film was formed on the copper surface when the electrode plate surface-space potential difference was 0 eV.

Next, the inventors examined the generation mechanism of the oxide film formed on the surface of the upper electrode plate 38. Specifically, it was examined whether the main factors for oxide film formation were oxygen radicals or oxygen ions.

First, in the plasma processing apparatus 10, a predetermined amount of oxygen gas and a small amount of argon gas were introduced into the processing space S, and high frequency power of 40 MHz and 2 MHz was applied to the processing space S to generate plasma. At this time, the ratio of the oxygen radical to the argon radical in the plasma was measured while changing the pressure in the processing space S. As a result, as shown in the graph of FIG. 2, it was found that the ratio of oxygen radicals to argon radicals increases as the pressure of the processing space S increases. That is, it turned out that oxygen radicals increase when the pressure of process space S is high.

On the other hand, in the plasma processing apparatus 10, a predetermined amount of oxygen gas and a small amount of argon gas were introduced into the processing space S, and high frequency power of 40 MHz and 2 MHz was applied to the processing space S to generate plasma. At this time, while changing the pressure in the processing space S (three pressures of 6.7 Pa (50 mTorr), 13.3 Pa (100 mTorr) and 26.7 Pa (200 mTorr)), the number of oxygen ions per unit time reaching the side wall member 45 is determined. Measured. At this time, the energy distribution of oxygen ion was also measured. As a result, as shown in the graph of FIG. 3, it was found that the number of oxygen ions per unit time reaching the side wall member 45 decreases as the pressure in the processing space S increases. In other words, it was found that when the pressure in the processing space S is high, the number of oxygen ions decreases.

The mechanism for explaining that the number of oxygen ions reaching the sidewall member 45 decreases as the pressure of the processing space S increases is difficult to explain clearly, but it is difficult to explain clearly in the technical common sense in the technical field to which the present invention belongs. Based on this, the inventors have inferred the two hypotheses described below.

(1) It is known that when the pressure in the processing space in which the plasma is generated is increased, the plasma is localized in the vicinity of the electrode applying high frequency power to the processing space. Also in the processing space S, the plasma generated from the oxygen gas is ubiquitous in the vicinity of the susceptor 12, and as a result, the plasma in the vicinity of the side wall member 45 is reduced, so that the vicinity of the side wall member 45 is reduced. The number of oxygen ions decreases. As a result, the number of oxygen ions reaching the side wall member 45 is reduced.

(2) The flow rate (ion flux) γ _i of the ions flowing into the side of the processing chamber can be expressed by the following equation (1).

N _i represents an ion density in a sheath occurring near the side wall member 45, Te represents an electron temperature, and M represents an ion mass.

Here, it is known that an electron temperature will become low when the pressure of a process space becomes high. Therefore, when the pressure of the processing space is increased from the above equation (1), the flow rate of ions flowing into the side of the processing chamber is reduced. That is, as the pressure in the processing space S increases, the number of oxygen ions reaching the side wall member 45 decreases.

As described above, when the pressure in the processing space S is lowered, the oxide film is more easily formed (see Table 1), and the number of oxygen ions increases, so that the formation of the oxide film and the number of oxygen ions have a close relationship, that is, It has been found that oxygen ions are the main cause of oxide film formation.

In addition, from the above knowledge, in order to suppress the formation of an oxide film on the surface of the upper electrode plate 38, reducing the number of oxygen ions reaching the surface of the upper electrode plate 38, and furthermore, in the processing space S It turned out that it is good to reduce the density of oxygen ions.

As a method of reducing the number of oxygen ions reaching the surface of the upper electrode plate 38, in addition to the method of increasing the pressure in the processing space S described above, a method of making the electrode plate surface-space potential difference to zero and a high frequency power of 40 MHz A method of reducing the size of may be considered. These methods are described below.

(1) Method of making electrode surface-space potential difference at 0 eV

When the electrode plate surface-space potential difference is 0 eV, since oxygen ions present in the processing space S do not enter the upper electrode plate 38, hardly reach the surface of the upper electrode plate 38, and as a result, the upper portion The number of oxygen ions reaching the surface of the electrode plate 38 can be reduced. Furthermore, as shown in Table 3 above, when the electrode plate surface-space potential difference is 0 eV, since no oxide film is formed on the surface of the upper electrode plate 38, the present method is applied to the surface of the upper electrode plate 38. It was confirmed that it is effective for the prevention of the formation of an oxide film.

(2) A method of reducing the size of 40 MHz high frequency power

When the magnitude of the high frequency power of 40 MHz is reduced, the amount of plasma generated in the processing space S, and further, the amount of oxygen ions is reduced. As a result, the number of oxygen ions reaching the surface of the upper electrode plate 38 from the processing space S can be reduced. Furthermore, as shown in Table 2 above, when the size of the high frequency power of 40 MHz is 500 W or less, since no oxide film is formed on the surface of the upper electrode plate 38, the present method also uses the upper electrode plate 38. It was confirmed that it is effective for preventing the formation of an oxide film on the surface of.

On the other hand, as shown in the said Table 3, even if the electrode plate surface-space potential difference is 150 eV or more, the knowledge that an oxide film was not formed in the surface of the upper electrode plate 38 was acquired. Since this finding is inconsistent with the above-described method of setting the electrode surface plate-space potential difference to 0 eV, the present inventors pay attention to the sputtering of the upper electrode plate 38 surface by oxygen ions, and argon molecules similar in molecular weight to oxygen molecules. The change in the sputtering yield when the potential difference was changed was calculated using a calculation model of argon radicals generated from. As a result, as shown in the graph of FIG. 4, sputtering did not generate | occur | produce from 0eV to a predetermined electric potential difference, and when it exceeds the predetermined electric potential difference, it turned out that sputtering rate becomes large as electric potential difference becomes large.

As mentioned above, this inventor came to infer the following hypotheses. That is, in the case where the electrode plate surface-space potential difference is 0 eV, since the oxygen ions hardly reach the surface of the upper electrode plate 38 as described above, no oxide film is formed (Fig. 5 (a)).

When the electrode plate surface-space potential difference is about 100 eV, only low energy oxygen ions are introduced to the surface of the upper electrode plate 38. At this time, since the collision energy between the oxygen ions and the upper electrode plate 38 surface is small, the oxygen ions adhere to the upper electrode plate 38 surface and react with silicon of the upper electrode plate 38 to form an oxide. As a result, an oxide film is formed on the surface of the upper electrode plate 38 (Fig. 5 (b)).

When the electrode plate surface-space potential difference is 150 eV or more, not only oxygen ions of low energy but also oxygen ions of high energy are introduced into the surface of the upper electrode plate 38. The low energy oxygen ions that reach the surface of the upper electrode plate 38 are attached to the surface of the upper electrode plate 38 to react with the silicon of the upper electrode plate 38 to form an oxide, but the high energy oxygen ions and the upper electrode Since the collision energy of the surface of the plate 38 is large, the oxide is removed by sputtering with high energy oxygen ions. As a result, no oxide film is formed on the surface of the upper electrode plate 38 (Fig. 5 (c)).

This invention is based on the some knowledge obtained from the above.

Hereinafter, the cleaning method of the substrate processing chamber which concerns on Example 1 of this invention is demonstrated.

6 is a flowchart of the cleaning method of the substrate processing chamber according to the present embodiment.

In FIG. 6, first, in the plasma processing apparatus 10 in which the reaction product adheres to the surface of the upper electrode plate 38, the wafer W subjected to the RIE treatment is carried out from the substrate processing chamber 11 (step S61). . Subsequently, oxygen gas is introduced from the gas introduction shower head 34 into the processing space S (step S62), and a high frequency power of 40 MHz is applied to the processing space S to generate a plasma, thereby removing the dry cleaning process. Processing) (step S63) (first plasma processing step).

In step S63, the pressure of the processing space S is set to 26.7 kPa to 80.0 kPa by the APC valve 15. When the upper limit of the pressure is set to 80.0 kPa, the density of oxygen radicals generated from the oxygen gas becomes too high when it exceeds 80.0 kPa, which is used for sealing the chamber (chamber lid) of the substrate processing chamber 11 and piping. This is because damage caused by sealing members such as O-rings becomes too large. In addition, the magnitude of the high frequency power of 2 MHz supplied from the other high frequency power supply 46 to the susceptor 12 is set to 0W. In other words, the high frequency power of 2 MHz is not supplied to the susceptor 12. At this time, since no potential potential occurs due to the high frequency power of 2 MHz on the surface of the upper electrode plate 38, the electrode plate surface-space potential difference becomes 0 eV. In addition, the size of the 40 MHz high frequency power supplied from the high frequency power supply 20 to the susceptor 12 is set to 500 W or less.

In step S63, oxygen ions and oxygen radicals are generated from the oxygen gas by the high frequency power of 40 MHz in the processing space S. FIG. Among these, oxygen radicals (first plasma) react with the reaction products attached to the surface of the upper electrode plate 38 to decompose and remove the reaction products. On the other hand, since the pressure in the processing space S is set to 26.7 kPa to 80.0 kPa, the electrode plate surface-space potential difference is 0 eV, and the size of the 40-MHz high-frequency power is set to 500 W or less, the surface of the upper electrode plate 38 The number of oxygen ions which reach | attains to becomes small, and formation of an oxide film on the surface of the upper electrode plate 38 is suppressed. However, in step S63, a small amount of high energy oxygen ions reach the surface of the upper electrode plate 38, and as a result, a small amount of oxide is generated by the reaction of oxygen ions and silicon in the upper electrode plate 38. It is also possible to adhere to the surface of the upper electrode plate 38.

Next, oxygen ions, oxygen radicals and gases generated by decomposition of the reaction product in the processing space S are discharged through the exhaust flow path of the plasma processing apparatus 10 (step S64), and the process is performed from the gas introduction shower head 34. The tetrafluorocarbon (CF ₄ ) gas is introduced into the space S (step S65), and the oxide removal process described later is executed by applying a high frequency power of 40 MHz and 2 MHz to the processing space S to generate a plasma. (Step S66) (second plasma processing step).

In step S66, fluorine ions or fluorine radicals are generated from the tetrafluorocarbon gas by the high frequency power of 40 MHz and 2 MHz in the processing space S. Fluorine ions and fluorine radicals (second plasma) react with oxides attached to the surface of the upper electrode plate 38 to decompose and remove the oxides.

Next, gas generated by decomposition of fluorine ions, fluorine radicals and oxides in the processing space S is discharged through the exhaust flow path of the plasma processing apparatus 10 (step S67), and the present process is finished.

According to the above-described process of FIG. 6, the dry cleaning process is performed on the upper electrode plate 38 by oxygen radicals generated from oxygen gas introduced into the processing space S where the surface of the upper electrode plate 38 made of silicon is exposed. Next, an oxide removal treatment is performed on the upper electrode plate 38 by fluorine ions or fluorine radicals generated from the tetrafluorocarbon gas introduced into the processing space S. In the dry cleaning process, oxides generated from oxygen radicals and silicon and adhered to the surface of the upper electrode plate 38 are decomposed and removed by fluorine ions or fluorine radicals. Thereby, formation of the oxide film on the surface of the upper electrode plate 38 can be prevented. As a result, generation | occurrence | production of a particle can be prevented, and also generation | occurrence | production of the dielectric breakdown of an oxide film can be prevented, and the state of the plasma in RIE process etc. in process space S can be stabilized.

In the above-described process of FIG. 6, in the dry cleaning process (step S63), the pressure in the processing space S is set to 26.7 kPa to 80.0 kPa, and the magnitude of the high-frequency power of 2 MHz is set to 0 W so that the electrode plate surface-space Since the potential difference is 0 eV and the magnitude of the high frequency power of 40 MHz is set to 500 W or less, the number of oxygen ions reaching the surface of the upper electrode plate 38 decreases. Therefore, reaction of silicon and oxygen ions can be suppressed, and formation of the oxide film on the surface of the upper electrode plate 38 can be prevented reliably.

In the above-described process of Figure 6, in the oxide removal process (step S65), but the introduction of the 4 carbon fluoride gas in the processing space S from a gas introducing showerhead 34, the gas to be introduced is not limited to, C _X Fluorocarbon straight-chain saturated gas represented by _{F2X + 2} , for example, C ₂ F ₆ or C ₃ F ₈ may be used.

Next, the cleaning method of the substrate processing chamber according to the second embodiment of the present invention will be described.

This embodiment is basically the same in structure and operation as in the above-described first embodiment, the pressure of the processing space S in the dry cleaning process, the value of the electrode plate surface-space potential difference, and the high frequency power of 40 MHz and 2 MHz. The size of is only different from the first embodiment described above. Therefore, description of the same structure is abbreviate | omitted and only the operation different from Example 1 is demonstrated below.

7 is a flowchart of the cleaning method of the substrate processing chamber according to the present embodiment.

In Fig. 7, first, steps S61 and S62 described above are executed, and then dry cleaning processing (attachment removal processing) is performed by applying high frequency power of 40 MHz and 2 MHz to the processing space S to generate plasma. (Step S71) (First plasma processing step).

In step S71, the pressure in the processing space S is set to less than 26.7 kPa by the APC valve 15. Further, the magnitude of the 2 MHz high frequency power supplied from the other high frequency power supply 46 to the susceptor 12 is adjusted to set the electrode plate surface-space potential difference to 150 eV or more. Further, the size of the 40 MHz high frequency power supplied from the high frequency power supply 20 to the susceptor 12 is set larger than 500W.

In step S71, oxygen ions and oxygen radicals are generated from the oxygen gas by high frequency power of 40 MHz and 2 MHz in the processing space S. FIG. At this time, since the pressure of the processing space S is set smaller than 26.7 kPa, the electrode plate surface-space potential difference is set to 150 eV or more, and the magnitude of the high frequency power of 40 MHz is set larger than 500 W, the upper electrode plate 38 The number of oxygen ions that reach the surface of the silicon oxide does not decrease, and not only the low energy oxygen ions but also the high energy oxygen ions are introduced to the surface of the upper electrode plate 38. Among the oxygen ions introduced into the surface of the upper electrode plate 38, the low energy oxygen ions react with the silicon of the upper electrode plate 38 to form an oxide, but the high energy oxygen ions collide with the surface of the upper electrode plate 38. To remove oxides produced from low-energy oxygen ions by sputtering. However, in step S71, the oxide is not completely removed, and there is a possibility that some amount of oxide remains on the surface of the upper electrode plate 38.

Next, the above-described steps S64 to S67 are executed. In step S66, some oxide remaining on the surface of the upper electrode plate 38 is decomposed by fluorine ions or fluorine radicals and removed. And this process is complete | finished.

According to the above-described process of FIG. 7, in the dry cleaning process (step S71), since the electrode plate surface-space potential difference is set to 150 eV or more, the high energy of oxygen ions introduced into the surface of the upper electrode plate 38 is increased. Oxygen ions collide with the surface of the upper electrode plate 38 to remove oxides attached to the surface of the upper electrode plate 38 by sputtering. Therefore, formation of the oxide film on the surface of the upper electrode plate 38 can be prevented reliably.

In the cleaning method of the substrate processing chamber according to each of the above-described embodiments, the wafer W is not contained in the substrate processing chamber 11, but may be executed while the wafer W is accommodated in the substrate processing chamber 11.

For example, in the plasma processing apparatus 10, a wafer W having an antireflection film (BARC film) and an insulating layer formed on a surface thereof is accommodated in the substrate processing chamber 11, a tetrafluorocarbon gas is introduced into the processing space S, and the tetrafluoride. Fluorine ions or fluorine radicals are generated from the carbon gas, the antireflection film is removed by the fluorine ions or fluorine radicals, and the antireflection film is removed to perform RIE treatment on the exposed insulating layer. At this time, since a reaction product adheres to the surface of the upper electrode plate 38, oxygen gas is introduced into the processing space S, oxygen ions and oxygen radicals are generated from the oxygen gas, and reacted with oxygen ions or oxygen radicals. Remove the product. Upon removal of the reaction product, an oxide film is formed on the surface of the upper electrode plate 38 due to oxygen ions. This oxide film is removed by fluorine ions or fluorine radicals generated at the time of removal of the antireflection film, which is executed after the new wafer W having the antireflection film and the insulating layer formed on the surface is accommodated in the substrate processing chamber 11. Thereby, manufacture of the semiconductor device from the wafer W and washing of the substrate processing chamber 11 can be performed simultaneously, and productivity can be improved.

In the plasma processing apparatus 10 described above, the upper electrode plate 38 is purely made of silicon, but the upper electrode plate 38 may be made of a material containing silicon.

In addition, in the method of cleaning the substrate processing chamber according to the above-described embodiments, the formation of the oxide film on the surface of the upper electrode plate 38 is prevented, but the method of cleaning the substrate processing chamber according to the embodiments described above The component to which formation is prevented is not limited to this, For example, the side wall member 45 and the susceptor side covering member 60 may be sufficient.

In addition, in the cleaning method of the substrate processing chamber which concerns on each Example mentioned above, although the film | membrane removed was an oxide film, the film | membrane removed is not limited to this, A nitride film may be sufficient.

In the above-described plasma processing apparatus 10, the substrate subjected to RIE processing or the like is not limited to a semiconductor wafer for semiconductor devices, and various substrates used for liquid crystal display (LCD) or flat panel display (FPD), A photomask, CD board | substrate, a printed board, etc. may be sufficient.

In addition, an object of the present invention is to supply a storage medium storing program codes of software for realizing the functions of the above-described embodiments to a system or an apparatus, and the computer (or CPU or MPU, etc.) of the system or apparatus is stored. It is also achieved by reading and executing the program code stored in the medium.

In this case, the program code itself read out from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD Optical discs, such as -RW and DVD + RW, a magnetic tape, a nonvolatile memory card, ROM, etc. can be used. Alternatively, the program code may be downloaded via a network.

In addition, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the operating system (OS) or the like operating on the computer is part of the actual processing based on the instruction of the program code. It also includes a case where all of them are performed, and the processing realizes the functions of the above-described embodiments.

Furthermore, after the program code read out from the storage medium is written into the memory provided in the function expansion port inserted into the computer or the function expansion unit connected to the computer, the expansion function is extended based on the instruction of the program code. A CPU or the like provided in the board or the expansion unit performs part or all of the actual processing, and the processing includes the case where the functions of the above-described embodiments are realized.

According to the cleaning method of the substrate processing chamber according to the first aspect and the storage medium according to the seventh aspect, the processing chamber is formed by a first plasma generated from an oxygen gas introduced into a space where at least a part of a component in the processing chamber containing at least silicon is exposed. The deposit removal treatment is performed on the internal parts, and then the oxide removal processing is performed on the parts in the processing chamber by the second plasma generated from the tetrafluorocarbon gas introduced into the space. In the deposit removal treatment, oxides generated from the first plasma and silicon and adhered to the surface of the component in the processing chamber are removed by the second plasma. Thereby, formation of the oxide film in the surface of the component in a process chamber can be prevented. As a result, the generation of particles can be prevented.

According to the cleaning method of the substrate processing chamber according to the second aspect, since the components in the processing chamber are disposed opposite to the substrate loaded into the space and are connected to a DC power source, the formation of an oxide film on the surface of the electrode is prevented. The occurrence of dielectric breakdown of the oxide film can be prevented and the state of the plasma can be stabilized in the space.

According to the cleaning method of the substrate processing chamber according to the third aspect, the pressure in the space in the first plasma processing step is set to 26.7 kPa to 80.0 kPa. The main cause of oxide generation attached to the surface of the components in the process chamber is the reaction of silicon and oxygen ions, but increasing the pressure in the space reduces the number of oxygen ions reaching the surface of the components in the process chamber. Therefore, reaction of silicon and oxygen ions can be suppressed, and formation of the oxide film on the surface of the component in a process chamber can be prevented reliably.

According to the cleaning method of the substrate processing chamber according to the fourth aspect, the ions in the first plasma, which are applied to the space in the first plasma processing step, are generated on the surface of the component in the processing chamber due to the high frequency power of the trackable frequency. The difference between the potential and the space potential is set to 150 eV or more. As the difference between the potential generated on the surface of the component in the processing chamber and the potential in the space increases, the sputtering rate on the surface of the component in the processing chamber due to oxygen ions increases. Therefore, the oxide adhering to the surface of the component in a process chamber can be removed by sputtering by oxygen ion, and formation of the oxide film in the surface of the component in a process chamber can be prevented more reliably.

According to the cleaning method of the substrate processing chamber according to the fifth aspect, since the magnitude of the high frequency power of the frequency that can be followed by the ions in the first plasma applied to the space in the first plasma processing step is set to 0W, The difference between the potential generated on the surface of the component and the potential of the space can be reduced, and the number of oxygen ions reaching the surface of the component in the processing chamber can be further reduced. Therefore, formation of the oxide film on the surface of the component in a process chamber can be prevented more reliably.

According to the cleaning method of the substrate processing chamber according to the sixth aspect, in the first plasma processing step, since the magnitude of the high frequency power of the frequency at which the ions in the first plasma cannot be applied to the space is not set to 500 W or less, The density of oxygen ions generated in the space can be lowered, the number of oxygen ions reaching the surface of the component in the processing chamber can be further reduced, and the formation of an oxide film on the surface of the component in the processing chamber can be more reliably prevented. have.

According to the substrate processing chamber according to the eighth aspect, oxygen gas is introduced into a space where at least a part of a component in a processing chamber including silicon is exposed, a first plasma is generated from the introduced oxygen gas, and the first plasma is removed. When the tetrafluorocarbon gas is introduced into the space and the tetrafluorocarbon gas is introduced into the space, high frequency power is applied to the space to generate a second plasma. The first plasma removes deposits attached to the surface of the component in the process chamber, and the second plasma is generated from the first plasma and silicon to remove oxides attached to the surface of the component in the process chamber. Thereby, formation of the oxide film in the surface of the component in a process chamber can be prevented. As a result, the generation of particles can be prevented.

Claims (8)

delete delete delete A substrate processing chamber having a space into which a substrate is loaded and performing plasma processing on the substrate in the space, wherein at least a portion of the substrate is exposed, and the substrate processing chamber is provided with components in the processing chamber containing at least silicon. As a method, A first plasma treatment step of performing a deposit removal treatment on the components in the processing chamber by the first plasma generated from the oxygen gas introduced into the space; A second plasma treatment step of removing the oxide film formed during the first plasma treatment step on the surface of the component in the processing chamber by the second plasma generated from the tetrafluorocarbon gas introduced into the space; Including but not limited to: The difference between the potential generated on the surface of the component in the processing chamber and the potential in the space due to the high frequency power of the frequency that the ions in the first plasma applied to the space in the first plasma processing step can follow. Set to 150 eV or higher The cleaning method of the substrate processing chamber characterized by the above-mentioned. A substrate processing chamber having a space into which a substrate is loaded and performing plasma processing on the substrate in the space, wherein at least a portion of the substrate is exposed, and the substrate processing chamber is provided with components in the processing chamber containing at least silicon. As a method, A first plasma treatment step of performing a deposit removal treatment on the components in the processing chamber by the first plasma generated from the oxygen gas introduced into the space; A second plasma treatment step of removing the oxide film formed during the first plasma treatment step on the surface of the component in the processing chamber by the second plasma generated from the tetrafluorocarbon gas introduced into the space; Including but not limited to: The magnitude of the high frequency power at a frequency to which the ions in the first plasma can be applied to the space in the first plasma processing step is set to 0W The cleaning method of the substrate processing chamber characterized by the above-mentioned. A substrate processing chamber having a space into which a substrate is loaded and performing plasma processing on the substrate in the space, wherein at least a portion of the substrate is exposed, and the substrate processing chamber is provided with components in the processing chamber containing at least silicon. As a method, A first plasma treatment step of performing a deposit removal treatment on the components in the processing chamber by the first plasma generated from the oxygen gas introduced into the space; A second plasma treatment step of removing the oxide film formed during the first plasma treatment step on the surface of the component in the processing chamber by the second plasma generated from the tetrafluorocarbon gas introduced into the space; Including but not limited to: The magnitude | size of the high frequency electric power of the frequency which the ion in the said 1st plasma cannot apply to in the said space in the said 1st plasma processing step is set to 500 W or less. The cleaning method of the substrate processing chamber characterized by the above-mentioned. delete delete

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