JP2010205872A - Plasma cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain plasma cleaning at low consumption for an electrode of placing a substrate to be processed, in a step of plasma cleaning the inside of a processing container without a substrate to be processed, in a plasma processing apparatus for semiconductor manufacturing. <P>SOLUTION: While plasma cleaning is continued, magnetic field produced by a magnetic field generator 151 from the outside of a processing container 100 produces electron cyclotron resonance around the outer periphery of the electrode 112 for placement within the processing container, and plasma density is reduced on the electrode 112 for placement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning method (plasma cleaning method) for cleaning a processing chamber while suppressing the consumption of a processing substrate mounting electrode in a plasma processing apparatus applied in the semiconductor manufacturing field.

  In recent years, with the miniaturization and complication of semiconductor devices, plasma processing apparatuses have been frequently used in the manufacturing process. However, in the manufacturing process, when the plasma processing is performed by the plasma processing apparatus, the foreign matter scattered and deposited in the processing chamber every time the plasma processing is performed peels off and scatters from the processing chamber and adheres to the semiconductor device. Reduce device manufacturing yield. In order to prevent such a decrease in yield, it is necessary to clean the processing chamber before the foreign matter accumulated in the processing chamber is peeled off.

  Such processing chamber cleaning methods include a wet cleaning method in which a processing container is opened to the atmosphere and cleaning is performed using a chemical solution, and a dry cleaning method in which cleaning plasma is generated in the processing chamber for cleaning. Recently, a dry cleaning method that can perform cleaning without opening the processing chamber to the atmosphere so as not to lower the operating rate of the apparatus is widely used.

  This dry cleaning method includes a method of performing cleaning with a non-product substrate mounted on a processing substrate mounting electrode in a processing chamber (see Patent Document 1), and a method of cleaning without mounting a substrate. (See Patent Document 2) and the like. In the above-described method of cleaning with the non-product substrate placed on the electrode, there may be a problem that foreign matter remains in the shadowed area from the cleaning plasma due to the non-product substrate. From the viewpoint of reduction and improvement of throughput, a cleaning method that does not mount a substrate, which will be described later, has been frequently used.

  However, in this cleaning method in which the substrate is not placed on the electrode, the substrate mounting electrode is directly exposed to the cleaning plasma, so that the substrate adsorption film on the surface of the substrate mounting electrode is consumed and plasma processing is performed. Since the contact area with the processing substrate changes, the temperature uniformity on the substrate changes each time the processing is continued. Due to this change over time, the finished state of the product substrate deteriorates. For this reason, in order to prevent the consumption of the adsorption film, there is a method of accurately grasping the end point of cleaning at which foreign matter in the processing chamber disappears and minimizing the cleaning time (see Patent Document 3). In addition, during processing of the substrate, the mounting electrode connected to the high frequency power source is cleaned in an apparatus system that applies a high frequency voltage from a high frequency power source connected to the mounting electrode and draws ions in the plasma to the substrate. Among them, a method of suppressing electrode scraping by cutting off an output from a high-frequency power source connected to a mounting power source to obtain a floating potential is disclosed (see Patent Document 4).

JP 2004-165644 A JP 2008-251967 A JP 2003-293138 A JP 2006-19626 A

  However, in the former method (Patent Document 3), the amount and thickness of the foreign matter adhering to the processing chamber is not constant in the entire processing chamber. For example, even after the foreign matter around the electrode is removed, If foreign matter remains, the cleaning process is continued while the substrate adsorbing film is consumed. Therefore, in all cases, the consumption of the electrode cannot be suppressed. Further, in order to accurately grasp the end point of cleaning, it is necessary to install a mechanism in the apparatus that has nothing to do with substrate processing for measuring foreign matter, which increases the manufacturing cost of the apparatus.

  In addition, regarding the method of setting the mounting electrode to the floating potential during the latter cleaning (Patent Document 4), in the apparatus used in the research by the inventors, the cleaning is performed in a state where the power supply to the mounting electrode is stopped. Even when the treatment was performed, it was not possible to sufficiently suppress the consumption of the substrate adsorption film.

  An object of the present invention is to provide a plasma cleaning method in which consumption of a mounting electrode (sample stage) and a substrate adsorption film is suppressed in a cleaning process in which cleaning is performed without placing a substrate on the mounting electrode. It is in.

In order to achieve the above-mentioned object, the present invention supplies gas into a vacuum container having electrodes arranged opposite to each other, and is placed on a processing substrate placing surface on a sample stage that becomes one electrode. In a method of plasma-cleaning the inside of the vacuum container after plasma processing a substrate to be processed and before unloading the substrate to be processed or before processing the next substrate to be processed,
The plasma cleaning is a cleaning using a plasma generated by the action of the magnetic field and a high frequency electric field in the vacuum vessel, forming a magnetic field in the vacuum vessel,
The ECR magnetic field surface, which is the surface of the magnetic field strength that satisfies the electron cyclotron resonance (ECR) condition at the applied high frequency, exists in a space that is at least sandwiched between the electrodes facing the substrate mounting surface. And the magnetic field is controlled so as to exist outside the range in the vacuum vessel.

  Further, the present invention is the plasma cleaning method described above, wherein the ECR magnetic field surface during the plasma processing is at a position different from that during the plasma cleaning.

  Further, the present invention is characterized in that in the plasma cleaning method described above, the position where the ECR magnetic field plane crosses the central axis of the electrode is below the substrate mounting surface of the sample stage.

  Further, the present invention is characterized in that in the plasma cleaning method described above, the position where the ECR magnetic field plane crosses the central axis of the electrode is above the electrode facing the sample stage.

  Further, the present invention is the plasma cleaning method described above, wherein the magnetic field has a vertical component with respect to a horizontal plane of the electrode facing the sample stage, and has a magnetic force line distribution that is axisymmetric with respect to a central axis. And

  Moreover, the present invention is characterized in that, in the plasma cleaning described above, the magnetic field has a magnetic field (magnetic line distribution) that diffuses from the electrode facing the sample stage toward the sample stage.

  In the plasma cleaning described above, the high-frequency electric field is formed by a high frequency applied to an electrode facing the sample stage.

  Moreover, the present invention is characterized in that, in the above-described plasma cleaning, the magnetic field is formed by two or more systems of electromagnetic coils that allow current to flow in the circumferential direction with respect to the processing chamber.

  Further, the present invention provides the above-described plasma cleaning, in which the magnetic field is applied so that the ECR magnetic field surface does not exist in the upper space inside the outer diameter of the ring-shaped component placed on the outer periphery of the substrate mounting portion. It is characterized by controlling.

  Further, the present invention is characterized in that, in the plasma cleaning described above, the electric field formed in the processing chamber during the cleaning has a frequency of 100 to 500 MHz.

  In the plasma cleaning described above, the present invention is characterized in that no high frequency is applied to the sample stage during cleaning.

  Further, the present invention provides a plasma processing apparatus in which the lower electrode and the upper electrode for mounting the substrate are opposed to each other, and is provided on the upper electrode without mounting the substrate on the lower electrode after processing the product substrate. A high-frequency voltage is applied to the cleaning gas introduced from the gas hole into the processing chamber by a high-frequency power source connected to the upper electrode from the outside of the processing container so as to generate cleaning plasma, and so that it is adjacent to the processing container outside the processing container. Including a cleaning step of generating a magnetic field diffusing from the upper electrode to the lower electrode in the processing vessel from the installed magnetic field generator to form a curved electron cyclotron resonance (hereinafter referred to as ECR) magnetic field distributed on the outer periphery of the lower electrode It is characterized by.

  According to the present invention, it is possible to suppress the consumption of the sample stage (lower electrode) by increasing the plasma density at the outer periphery of the sample stage (lower electrode). Thereby, since the inside of the processing container can be sufficiently cleaned without worrying about the consumption of the lower electrode, the foreign matter in the processing container is reduced, and the yield of the product substrate is improved.

The figure which showed the schematic cross section of the plasma etching apparatus to which this invention is applied. The figure which shows the process chamber detail during a substrate process of the apparatus used for this invention. The figure which shows the plasma distribution in the process chamber during a substrate process of the apparatus used for this invention. The figure which shows the process chamber details in the washing | cleaning process of this invention Example 1. FIG. The figure which shows plasma distribution in the process chamber in the cleaning process of this invention Example 1. FIG. The figure which shows the process chamber details in the washing | cleaning process of this invention Example 2. FIG. The figure which shows plasma processing chamber plasma distribution in the washing | cleaning process of this invention Example 2. FIG. The figure which shows the effect anticipated using this invention Example 3 besides electrode consumption suppression.

  The above-mentioned patent document 4 is a method of suppressing the consumption of the electrode by turning off the voltage application to the mounting electrode (sample stage) during cleaning, thereby setting the potential of the mounting electrode in a floating state. According to this method, the effect of attracting ions in the plasma is reduced, so that the amount of consumption of the mounting electrode is smaller than when a voltage is applied to the mounting electrode. However, since a potential corresponding to the surrounding situation is also generated in the mounting electrode in a floating state, the electrode is consumed due to the ion attracting effect by the generated potential.

  In the plasma processing apparatus in which the upper electrode and the lower electrode are opposed to each other, the researchers of the present invention perform plasma treatment between the upper electrode and the lower electrode when performing the cleaning process without placing the substrate on the lower electrode. It was discovered that the consumption of the lower electrode and the substrate adsorption film can be suppressed by reducing the density.

  As a method of reducing the plasma density on the lower electrode, in the present invention, a method of applying a magnetic field to the generated plasma from the outside of the processing vessel and controlling the plasma density distribution is used. The high frequency excitation plasma has ECR magnetic field conditions depending on the frequency of the high frequency voltage when the plasma is generated. In this ECR magnetic field, plasma is efficiently generated by the resonance action, and the plasma density is increased. By generating a magnetic field condition that satisfies the ECR magnetic field condition on the outer periphery of the lower electrode, the plasma density on the outer periphery of the lower electrode increases and the plasma density on the lower electrode decreases. Hereinafter, an optimum mode for controlling the magnetic field distribution will be described with reference to the drawings.

  FIG. 1 shows a cross section of a plasma processing apparatus according to the present embodiment. The plasma processing apparatus according to the present embodiment can adjust the distance from the upper electrode inside the processing container 100 and has a substrate adsorption film 111 made of a dielectric (for example, alumina) on the processing substrate mounting surface. The movable electrode 112 (sample stage, lower electrode) and the upper electrode 121 installed at a position facing the movable electrode 112 are provided. Further, the upper electrode 121 is connected to a plasma generating high frequency power source 122 installed outside the processing container, and includes a gas introduction mechanism 123 for introducing a plasma generating gas from the outside of the processing container. In addition, the movable electrode 112 attracts ions from plasma generated during product substrate processing, and applies a bias applying high-frequency power source 113 for performing substrate processing, and for adsorbing the processing substrate W to the substrate adsorption film 111 during processing. A cooling gas introduction mechanism 116 for introducing a gas between the substrate adsorbing film 111 and the processing substrate W in order to cool the processing substrate W being processed is connected to a DC power source 115 having a filter circuit 114.

  In addition, the processing container 100 includes a gate valve 131 for carrying in and out the processing substrate W, exhausts the gas introduced from the gas introduction mechanism 123 and reaction products generated by various plasma processing, and causes a predetermined pressure in the processing chamber. The exhaust means 141 can be maintained. Further, a means for generating a magnetic field inside the processing container 100 is provided outside the processing container. This means consists of two stages, upper and lower, and is installed so as to surround the upper electrode from outside the processing vessel 100, and generates a magnetic field that is axisymmetric with respect to the central axis of the movable electrode 112 by flowing current in the circumferential direction of the upper electrode 121. The coil 151 is provided.

  According to this embodiment, the processing substrate W transferred to the processing container 100 through the gate valve 131 is placed on the substrate adsorption film 111 on the movable electrode 112. After the processing substrate W is transported, the distance between the movable electrode 112 and the upper electrode 121 is set to a predetermined inter-electrode distance (for example, 20 to 30 mm) by the movable electrode 112. With the distance between the electrodes set, a gas (for example, C4F6, O2, Ar) used for plasma generation is introduced from the gas introduction mechanism 123, and the processing chamber is maintained at a constant pressure by the exhaust means 141 (for example, 1 to 1). 10 Pa). Thereafter, a high-frequency voltage (for example, a frequency of 100 to 500 MHz, power of 200 to 600 W) is applied to the upper electrode 121 by a high-frequency power source 122 for plasma generation.

  Here, a current is passed through the coil 151 (the total amount of current flowing through the upper and lower two-stage coils is, for example, 1 to 4 A), and a magnetic field is generated in the processing container. Plasma is generated in the processing chamber by the applied high-frequency voltage and magnetic field, and etching of the processing substrate W is started. At this time, a high frequency voltage (for example, frequency 1 to 10 MHz, power 2 to 7 kW) is applied to the movable electrode 112 from the bias applying high frequency power source 113, and at the same time, an adsorption voltage (for example, 1 to 1 kV) is applied from the DC power source 115. The etching process is performed while a gas (for example, He) is introduced from the cooling gas introduction mechanism 116 and the processing substrate W is cooled.

  FIG. 2 shows the inside of the processing container during the processing of the processing substrate W. The processing substrate W is transferred into the processing container, and the etching process is performed in a state where the processing substrate W is placed on the substrate adsorption film 201. A diffusion magnetic field that diffuses toward the electrode is generated in the processing container in which the processing substrate is being etched, as indicated by the lines of magnetic force 204 by the coil installed outside the processing container. The diffusion magnetic field forms a curved ECR magnetic field 205 of 60 to 80 G between the upper electrode 203 and the movable electrode 202 and the substrate adsorption film 201 or on the upper electrode 203. In FIG. 2, the magnetic field lines 204 are drawn in the direction from the upper electrode 203 to the movable electrode 202. However, considering the principle of the ECR phenomenon, the same result can be obtained even if the direction of the magnetic field lines is opposite to this figure. It is clear that it is obtained.

  FIG. 3 shows the state of plasma in the processing container during the etching process. According to the ECR magnetic field surface 304 passing between the substrate adsorption film 301 and the upper electrode 302, the plasma density of the plasma 303 on the processing substrate W increases, and a high-density plasma area 303 is formed. This increase in plasma density can improve the etching performance during substrate processing.

  Further, since the ECR magnetic field surface 304 exists outside the vacuum vessel as it goes outside the outermost diameter of the processing substrate W, the plasma does not become dense outside the processing substrate W.

  When the processing substrate W is etched as described above, foreign substances such as reaction products scattered by the etching accumulate in the processing container. Usually, when processing the product substrate W, in order to improve the throughput of the apparatus, the processing substrate is continuously carried into the processing container and processed. However, when processing using a highly depositable gas, foreign matter accumulates in the processing container in the processing of one substrate, and if the next substrate is processed in that state, the processing of the processed substrate Yield may be reduced. Therefore, in this embodiment, cleaning is performed once for one substrate processing.

  A mechanism for carrying out the cleaning process will be described with reference to FIG. According to the present embodiment, in the processing container 100 after the substrate processing is completed and the processing substrate W is unloaded, the cleaning process is performed without placing the processing substrate on the movable electrode 112 and the substrate adsorption film 111. . After the processing substrate is carried out, the height of the movable electrode 112 is set so as to be the distance between the electrodes used in the cleaning process (for example, 20 to 80 mm). In this embodiment, cleaning is performed at the same inter-electrode distance as in the substrate processing so that the foreign matter accumulated in the processing container during the substrate processing does not become a shadow due to the upper and lower sides of the movable electrode 112. Thereafter, the inside of the processing container is evacuated by the exhaust means 141.

In this state, a cleaning gas (for example, O 2) is introduced from the gas introduction mechanism 123 through the upper electrode 121, and the inside of the processing container is held at a constant pressure (for example, 1 to 10 Pa) by the exhaust unit 141, and then plasma generation A high frequency voltage (for example, a frequency of 100 to 500 MHz, power of 600 to 1000 W) is applied from the high frequency power supply 122 for use, and a magnetic field is generated from the coil 151 at the same timing as the plasma processing of the substrate. Cleaning plasma is generated in the processing vessel by the applied high-frequency voltage and magnetic field. At this time, if the magnetic field applied to the cleaning plasma has the same magnetic field intensity as that during the substrate processing, the substrate adsorption film 111 is exposed to the high-density cleaning plasma and consumed. In this embodiment, in the cleaning process, a magnetic field having a strength different from that during substrate processing is generated, thereby generating an ECR magnetic field on the outer peripheral portion of the movable electrode, thereby suppressing consumption of the substrate adsorption film 111 and the mounting electrode 112. It is characterized by.
FIG. 4 shows the details inside the processing container during the cleaning process according to this embodiment. In this embodiment, when the current condition for flowing through the upper and lower two-stage coils 151 is set so that the magnetic fields generated from the upper and lower two-stage coils mutually intensify (for example, the direction of the current flowing through the upper coil is positive and the lower coil is When the direction of the flowing current is also positive), the magnetic field distribution in the discharge space between the upper electrode 403, the movable electrode 402, and the substrate adsorption film 401 becomes a divergent diffusion magnetic field indicated by the lines of magnetic force 404. In the magnetic field distribution indicated by the lines of magnetic force 404, the isomagnetic surface in the processing container is a parabolic isomagnetic surface that is convex downward. According to this isomagnetic surface, an ECR magnetic surface of 60 to 80G which is an ECR condition with the cleaning plasma (an ECR magnetic field surface which is a surface of a magnetic field intensity satisfying an electron cyclotron resonance (ECR) condition at an applied high frequency) 405 also has a downwardly parabolic distribution.

In this embodiment, the position where the downwardly convex parabolic ECR magnetic field surface 405 crosses the central axis of the movable electrode 402 is located below the upper surfaces of the substrate adsorption film 401 and the movable electrode 402, and the ECR magnetic field surface 405. The cleaning process is performed by controlling the current flowing through the coil so that a part of the magnetic field passes through the outer periphery of the movable electrode 402 and forms a magnetic field. Therefore, the ECR magnetic field surface, which is the surface of the magnetic field intensity that satisfies the electron cyclotron resonance (ECR) condition at the applied high frequency, is sandwiched between at least the electrode on the processing substrate mounting surface in the vacuum vessel. The magnetic field can be controlled so that it does not exist in the space within the range but exists outside the range.
In this embodiment, the total amount of current flowing through the upper and lower coils is, for example, 5 to 8A. The magnetic field has a vertical component with respect to the horizontal plane of the upper electrode 403 and has a magnetic force line distribution that is axisymmetric with respect to the central axis.

  FIG. 5 shows the state of the cleaning plasma in the processing vessel during the cleaning process using the downwardly convex ECR magnetic field surface. A high-density plasma 504 is generated outside the substrate adsorption film 501 and the movable electrode 502 by the downwardly projecting ECR magnetic field surface 505 generated from the coil. The high density plasma 504 reduces the plasma density between the upper electrode 503, the substrate adsorption film 501, and the movable electrode 502. Therefore, damage from the cleaning plasma to the substrate adsorption film 501 and the movable electrode 502 is suppressed, and the consumption amount is suppressed.

  In the above-described cleaning method, the downward convex ECR magnetic field surface has been described. However, the ECR magnetic field surface may be convex upward.

  FIG. 6 shows details inside the processing container being cleaned, and the configuration of the apparatus is the same as that shown in FIG. In this embodiment, when the current condition for flowing through the upper and lower coils is set so that the magnetic fields generated from the upper and lower coils are weakened near the upper electrode (for example, the direction of the current flowing through the upper coil is negative, the lower coil In the discharge space between the upper electrode 603, the substrate adsorption film 601 and the movable electrode 602, the magnetic field distribution in the discharge space shown by the magnetic lines of force 604 is a diffusion magnetic field. The isomagnetic field surface in the processing container of the diffusion magnetic field has an upwardly convex parabolic distribution. According to this isomagnetic surface, the ECR magnetic field surface 605 of 60 to 80 G, which is the ECR magnetic field condition of the cleaning plasma, also has an upwardly convex parabolic distribution.

  In the present embodiment, the upwardly projecting parabolic ECR magnetic field surface 605 is positioned above the upper electrode 603 so that the central axis of the upper electrode 603 is crossed, and part of the ECR magnetic field surface 605 is a substrate adsorption film. Cleaning is performed by controlling the current flowing through the coil so that it does not hang over 601 and the movable electrode 602. In this embodiment, the total amount of current flowing through the upper and lower coils is, for example, 5 to 8A.

  FIG. 7 shows the state of plasma in the processing container during the cleaning process using the upwardly convex ECR magnetic field surface. High-density plasma 704 is generated outside the substrate adsorption film 701 and the movable electrode 702 by the upwardly convex ECR magnetic field surface 705 generated by the above-described coil. The high density plasma 704 reduces the plasma density between the upper electrode 703, the substrate adsorption film 701 and the movable electrode 702. Therefore, damage from the cleaning plasma to the substrate adsorption film 701 and the movable electrode 702 is suppressed, and the consumption amount is suppressed.

  FIG. 8 explains further effects desired in addition to the electrode consumption suppression of the present invention in addition to the above-described embodiment. In addition to the system of FIG. 1, the system shown in FIG. 8 has a ring 806 made of a ring-shaped conductor or dielectric (for example, its material) on the outer periphery of the substrate adsorption film 801 to improve the etching performance of the outer periphery during substrate processing. Have Si, SiC, C, etc.). In this system, when the cleaning process using the downwardly projecting ECR magnetic field surface 805 described in the first embodiment is performed, the amount of current applied to the coil is controlled, so that a high-density plasma is generated outside the ring 806. 804 can be formed. Due to the high-density plasma 804, the plasma density between the upper electrode 803, the substrate adsorption film 801, the movable electrode 802, and the ring 806 is reduced. Due to the decrease in the plasma density, consumption due to the cleaning process of the substrate adsorption film 801 and the ring 806 can be suppressed.

  In the above-described embodiments, the description has been made using the system in which the high-frequency voltage for plasma generation is applied from the upper electrode. However, the above-described system is also used in the system for generating plasma by applying the high-frequency voltage for plasma generation from the movable electrode. By controlling the ECR magnetic field surface, it is clear that the plasma density on the movable electrode can be reduced as compared with the etching process, and consumption of the movable electrode and the substrate adsorption film can be suppressed. However, when a high-frequency voltage is applied from the movable electrode, a larger self-bias is applied to the movable electrode and the substrate adsorption film than when a high-frequency voltage is applied from the upper electrode, and the electrode consumption effect is reduced. A system for applying a higher frequency voltage was used.

  Further, according to the embodiment of the present invention, the plasma density at the outer peripheral portion of the movable electrode is increased, so that the outer peripheral portion of the movable electrode, to which foreign substances are likely to adhere, can be efficiently cleaned during substrate processing.

  In the above-described embodiment, the ECR magnetic field condition is set to 60 to 80 G. However, since the ECR magnetic field condition varies depending on the frequency at the time of plasma generation, it is obvious that the ECR magnetic field condition can take various values without being limited to the above range. is there.

  Further, in this embodiment, 100 MHz to 500 MHz (preferably 168 MHz to 224 MHz) is used as the high frequency for generating plasma, but the energy of ions incident on the substrate adsorption film is smaller than in the case of a frequency lower than 100 MHz. Therefore, damage to the substrate adsorption film can be further reduced.

  DESCRIPTION OF SYMBOLS 100 ... Processing container, 111 ... Substrate adsorption film, 112 ... Movable electrode (sample stand, lower electrode), 113 ... High frequency power supply for bias application, 114 ... Filter circuit, 115 ... DC power supply, 116 ... Cooling gas introduction mechanism, 121 ... Upper electrode, 122 ... high frequency power source for plasma generation, 123 ... gas introduction mechanism, 131 ... gate valve, 141 ... exhaust means, 151 ... coil, 201 ... substrate adsorption film, 202 ... movable electrode, 203 ... upper electrode, 204 ... magnetic field lines 205 ... ECR magnetic field surface, 301 ... substrate adsorption film, 302 ... upper electrode, 303 ... high density plasma, 304 ... ECR magnetic field surface, 401 ... substrate adsorption film, 402 ... movable electrode, 403 ... upper electrode, 404 ... magnetic field line, 405 ... ECR magnetic field plane, 501 ... substrate adsorption film, 502 ... movable electrode, 503 ... upper electrode, 504 ... high density plasma, 505 ... CR magnetic field surface, 601 ... substrate adsorption film, 602 ... movable electrode, 603 ... upper electrode, 604 ... magnetic field line, 605 ... ECR magnetic field surface, 701 ... substrate adsorption film, 702 ... movable electrode, 703 ... upper electrode, 704 ... high density Plasma, 705 ... ECR magnetic field, 801 ... Substrate adsorption film, 802 ... Movable electrode, 803 ... Upper electrode, 804 ... High density plasma, 805 ... ECR magnetic field, 806 ... Ring.

Claims (5)

The substrate to be processed is plasma-treated by supplying a gas into a vacuum container having electrodes disposed opposite to each other and placing the substrate to be processed on the sample substrate mounting surface on the sample table serving as one of the electrodes. In the method of plasma cleaning the inside of the vacuum vessel after unloading or before the next substrate processing,
The plasma cleaning is a cleaning using a plasma generated by the action of the magnetic field and a high frequency electric field in the vacuum vessel, forming a magnetic field in the vacuum vessel,
The ECR magnetic field surface, which is the surface of the magnetic field strength that satisfies the electron cyclotron resonance (ECR) condition at the applied high frequency, exists in a space that is at least sandwiched between the electrodes facing the substrate mounting surface. And the magnetic field is controlled so as to be outside the range in the vacuum vessel.   2. The plasma cleaning method according to claim 1, wherein the ECR magnetic field surface during the plasma processing is at a position different from that during the plasma cleaning.   2. The plasma cleaning method according to claim 1, wherein the position where the ECR magnetic field plane crosses the central axis of the electrode is located below the surface of the sample substrate to be processed.   2. The plasma cleaning method according to claim 1, wherein the position where the ECR magnetic field plane crosses the central axis of the electrode is above the electrode facing the sample stage.   2. The plasma cleaning according to claim 1, wherein the magnetic field is controlled so that the ECR magnetic field surface does not exist in an upper space inside the outer diameter of the ring-shaped component placed on the outer periphery of the substrate mounting portion. A plasma cleaning method.

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