JP2020029621A - Plasma treatment apparatus - Google Patents

Abstract

To perform membrane treatment stably by preventing a cylindrical electrode and a shield from contacting each other.SOLUTION: A plasma treatment apparatus comprises: a cylindrical electrode 10 having a lower end which is one end provided with an opening 11 and an upper end which is the other end closed, and for changing process gas into a plasma by introducing the process gas inside thereof and applying an electric voltage thereto; and a chamber 1 which is a vacuum container having an opening 1a. The cylindrical electrode 10 having an upper end mounted in the opening 1a through an insulating member 22 extends inside of the chamber 1. Moreover, the plasma treatment apparatus comprises: a turntable 3 which is a conveying part for conveying a work W to be treated by the process gas, to below the opening 11 of the cylindrical electrode 10; a shield 13 covering the cylindrical electrode 10 extending in the vacuum container, through a gap d; and a spacer 30 disposed in the gap d between the cylindrical electrode 10 and the shield 13 and made of an insulating material.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a plasma processing apparatus.

  2. Description of the Related Art In a manufacturing process of various products such as a semiconductor device, a liquid crystal display, and an optical disk, a thin film such as an optical film may be formed on a work such as a wafer or a glass substrate. The thin film can be formed by forming a film of a metal or the like on the work, or performing film processing such as etching, oxidation, or nitridation on the formed film.

  Film formation or film treatment can be performed by various methods, and one of them is one using plasma. In film formation, an inert gas is introduced into a chamber in which a target is placed, and a direct current is applied. The film is formed by causing ions of the inert gas that has been turned into plasma to collide with the target and depositing the material beaten from the target on the work. In the film processing, a process gas is introduced into a chamber in which electrodes are arranged, and a high-frequency voltage is applied to the electrodes. Film processing is performed by colliding ions of the process gas that has been turned into plasma with the film on the work.

  In order to perform such film formation and film processing continuously, a rotating table is mounted inside one chamber, and a plurality of film forming units and film processing units are arranged in the circumferential direction above the rotary table. There is a processing device (for example, see Patent Document 1). An optical film or the like is formed by holding and transporting the work on the rotary table and passing the work immediately below the film forming unit and the film processing unit.

  In a plasma processing apparatus using a rotary table, a cylindrical electrode having a closed upper end and an opening at a lower end (hereinafter, referred to as a “cylindrical electrode”) may be used as a film processing unit. When a cylindrical electrode is used, an opening is provided in the upper part of the chamber, and the upper end of the cylindrical electrode is attached to this opening via an insulator. The side wall of the cylindrical electrode extends into the chamber, and the opening at the lower end faces the rotary table with a slight gap. The chamber is grounded, the cylindrical electrode functions as the anode, and the chamber and the turntable function as the cathode. A process gas is introduced into the cylindrical electrode, and a high-frequency voltage is applied to generate plasma. Electrons contained in the generated plasma flow into the rotary table, which is the cathode. By passing the work held on the turntable below the opening of the cylindrical electrode, ions contained in the plasma collide with the work and perform film processing.

JP-A-2002-256428

  A cylindrical shield is attached to the chamber so as to cover the side wall of the cylindrical electrode extending inside. The shield is attached to the edge of the opening of the chamber and extends parallel to the side wall of the tubular electrode. The shield connected to this chamber also functions as a cathode. The shield is disposed so as to be opposed to the cylindrical electrode with a small gap so as not to contact the cylindrical electrode.

  In recent years, the size of a workpiece to be processed tends to be large, and an improvement in processing efficiency has been demanded. In order to reduce the weight that increases due to the enlargement of the cylindrical electrode, the cylindrical electrode tends to be thin. In the film processing, the temperature of the cylindrical electrode is greatly increased due to the generation of plasma, so that the thinned cylindrical electrode may be deformed by heat and come into contact with the shield. When the cylindrical electrode comes into contact with the shield, that is, when the voltage-applied electrode comes into contact with the grounded electrode, abnormal discharge occurs and the plasma becomes unstable. As a result, stable film processing may not be performed.

  An object of the present invention is to provide a highly reliable plasma processing apparatus capable of preventing contact between a cylindrical electrode and a shield and performing stable film processing in order to solve the above-described problems. I do.

  In order to achieve the above object, a plasma processing apparatus of the present invention has one end provided with an opening and the other end closed, and a process gas is introduced into the inside and a voltage is applied thereto. A cylindrical electrode for converting the process gas into plasma, a vacuum vessel having an opening, the cylindrical electrode having the other end attached to the opening via an insulating member, and a vacuum vessel extending therein; The work to be performed, a transport unit that transports below the opening of the cylindrical electrode, a shield that is connected to the vacuum container and covers the cylindrical electrode extending inside the vacuum container via a gap, And a spacer formed of an insulating material and provided in a gap between the cylindrical electrode and the shield.

  The spacer may have a block shape.

The spacer may have a surface facing the cylindrical electrode and a surface facing the shield having an area of 1 to 3 cm ² .

  The spacer may have an inclined portion inclined toward the shield at a corner of the surface facing the cylindrical electrode, which is located on the opening side of the vacuum vessel.

  The spacer may be fixed to the shield with a bolt made of an insulating material.

  The spacer may be provided near one end of the cylindrical electrode.

  The spacer may be installed near one end of the cylindrical electrode, near the other end, and near the middle between one end and the other end.

  The cylindrical electrode and the shield may have a rectangular cylindrical shape, and the spacer may be provided in a gap between the cylindrical electrode and the shield.

  By providing a spacer in the gap between the side wall of the cylindrical electrode and the shield, it is possible to prevent the contact between the cylindrical electrode and the shield and provide a highly reliable plasma processing apparatus capable of performing stable film processing. it can.

FIG. 1 is a plan view schematically showing a configuration of a plasma processing apparatus according to an embodiment of the present invention. It is AA sectional drawing of FIG. FIG. 2 is a cross-sectional view taken along the line BB of FIG. 1, and is a view of the film processing unit as viewed from the center of a turntable. It is an enlarged side view of a spacer. It is an enlarged front view of a spacer. It is a figure showing the state where a spacer was attached to a shield. It is a figure showing another example of a mode of installation of a spacer. As a comparative example, it is a diagram showing an aspect in which the insulating member covers the entire gap between the cylindrical electrode and the shield.

[Constitution]
Embodiments of the present invention will be specifically described with reference to the drawings.

  As shown in FIGS. 1 and 2, the plasma processing apparatus has a substantially cylindrical chamber 1. The chamber 1 is provided with an exhaust unit 2 so that the inside of the chamber 1 can be evacuated to a vacuum. That is, the chamber 1 functions as a vacuum container. An opening 1a is provided on the upper surface of the chamber 1, and a cylindrical electrode 10 described later is fitted into the opening 1a, and the inside of the chamber 1 is kept airtight. The rotating shaft 3 b penetrates the bottom of the chamber 1 and stands inside the chamber 1. A substantially circular rotary table 3 is attached to the rotary shaft 3b. A drive mechanism (not shown) is connected to the rotating shaft 3b. The driving mechanism drives the rotary table 3 to rotate about the rotary shaft 3b.

  Since the chamber 1, the rotary table 3, and the rotary shaft 3b function as cathodes in the plasma processing apparatus, it is preferable that the chamber 1, the rotary table 3, and the rotary shaft 3 be formed of a conductive metal member having low electric resistance. For example, the rotary table 3 may be formed by spraying aluminum oxide on the surface of a stainless steel plate member.

  On the upper surface of the turntable 3, a plurality of holding portions 3a for holding the work W are provided. The plurality of holding portions 3a are provided at equal intervals along the circumferential direction of the turntable 3. As the rotary table 3 rotates, the work W held by the holder 3a moves in the circumferential direction of the rotary table 3. In other words, a transport path (hereinafter, referred to as “transport path P”), which is a circular movement locus of the work W, is formed on the surface of the rotary table 3. The holding unit 3a can be, for example, a tray on which the work W is placed.

  Hereinafter, simply referring to “circumferential direction” means “circumferential direction of the rotary table 3”, and simply saying “radial direction” means “radial direction of the rotary table 3”. In the present embodiment, a flat substrate is used as an example of the work W, but the type, shape, and material of the work W to be subjected to plasma processing are not limited to specific ones. For example, a curved substrate having a concave portion or a convex portion at the center may be used. Further, a material containing a conductive material such as metal or carbon, a material containing an insulator such as glass or rubber, or a material containing a semiconductor such as silicon may be used.

  Above the turntable 3, a unit (hereinafter, referred to as a “processing unit”) for performing each process in the plasma processing apparatus is provided. The respective processing units are arranged so as to be adjacent to each other at a predetermined interval along the transport path P of the work W formed on the surface of the turntable 3. The process of each process is performed by the work W held by the holding unit 3a passing under each processing unit.

  In the example of FIG. 1, seven processing units 4 a to 4 g are arranged along the transport path P on the turntable 3. In the present embodiment, the processing units 4a, 4b, 4c, 4d, 4f, and 4g are film forming units that perform a film forming process on the work W. The processing unit 4e is a film processing unit that performs processing on a film formed on the work W by the film forming unit. In the present embodiment, the description will be made on the assumption that the film forming unit performs sputtering. Further, the description will be made on the assumption that the film processing unit 4e performs post-oxidation. Post-oxidation is a process of oxidizing a metal film by introducing oxygen ions or the like generated by plasma into the metal film formed by the film forming unit.

  Between the processing unit 4a and the processing unit 4g, there is provided a load lock unit 5 for carrying an unprocessed work W from the outside into the chamber 1 and carrying out the processed work W to the outside of the chamber 1. . In the present embodiment, the transport direction of the workpiece W is a clockwise direction in FIG. 1 from the position of the processing unit 4a to the processing unit 4g. Of course, this is an example, and the transport direction, the type of the processing unit, the arrangement order and the number are not limited to specific ones, and can be determined as appropriate.

  FIG. 2 shows a configuration example of the processing unit 4a which is a film forming unit. The other film forming units 4b, 4c, 4d, 4f, and 4g may be configured similarly to the film forming unit 4a, but other structures may be applied. As shown in FIG. 2, the film forming unit 4a includes a target 6 attached to the upper surface inside the chamber 1 as a sputtering source. The target 6 is a plate-like member made of a material deposited on the work W. The target 6 is installed at a position facing the work W when the work W passes below the film forming unit 4a. A DC power supply 7 for applying a DC voltage to the target 6 is connected to the target 6. In addition, a sputter gas introduction unit 8 for introducing a sputter gas into the chamber 1 is provided on the upper surface of the inside of the chamber 1 near the place where the target 6 is attached. As a sputtering gas, for example, an inert gas such as argon can be used. Around the target 6, a partition 9 for reducing the outflow of plasma is provided. As the power supply, a known power supply such as a DC pulse power supply or an RF power supply can be applied.

  2 and 3 show configuration examples of the film processing unit 4e. The film processing unit 4 e is provided on the upper surface inside the chamber 1 and has a cylindrical electrode 10. The cylindrical electrode 10 has a rectangular cylindrical shape, has an opening 11 at one end, and is closed at the other end. The cylindrical electrode 10 has one end having an opening (hereinafter, referred to as “lower end”) on the lower side, the closed other end (hereinafter, referred to as “upper end”) on the upper side, and an upper end provided on the upper surface of the chamber 1. The opening 1a is attached via an insulating member 22. The side wall of the cylindrical electrode 10 extends inside the chamber 1, and the opening 11 at the lower end faces the turntable 3. More specifically, a flange 10a that protrudes outward is provided at the upper end. The insulating member 22 is fixed to the lower surface of the flange 10a and the periphery of the opening 1a of the chamber 1 to keep the inside of the chamber 1 airtight. The insulating member 22 is not limited to a specific material, but may be made of a material such as polytetrafluoroethylene (PTFE).

  The opening 11 of the cylindrical electrode 10 is arranged at a position facing the transport path P formed on the turntable 3. That is, the rotary table 3 serves as a transport unit, which transports the work W and passes the work W directly below the opening 11. Then, a position immediately below the opening 11 is a passing position of the work W.

  As shown in FIG. 1, when viewed from above, the cylindrical electrode 10 has a fan shape whose diameter increases from the center to the outside in the radial direction of the turntable 3. Here, the fan shape means the shape of the fan surface portion of the fan. The opening 11 of the cylindrical electrode 10 is also fan-shaped. The speed at which the work W held on the turntable 3 passes below the opening 11 becomes slower toward the center in the radial direction of the turntable 3 and becomes faster as it goes outward. Therefore, if the opening 11 is simply a rectangle or a square, a difference occurs in the time when the workpiece W passes directly below the opening 11 between the center side and the outside in the radial direction. By increasing the diameter of the opening 11 from the center to the outside in the radial direction, the time during which the workpiece W passes through the opening 11 can be constant, and the plasma processing described later can be made uniform. However, a rectangular or square shape may be used as long as the difference between the passing times does not cause a problem in the product. The size of the cylindrical electrode 10 and the thickness of the wall surface are not limited to specific ones, but tend to be large and thin, for example, the width in the circumferential direction is 300 to 400 mm, the width in the radial direction is 800 mm, and the wall surface is Having a thickness of about 1 mm may be used.

  As described above, the cylindrical electrode 10 penetrates the opening 1 a of the chamber 1, and a part thereof is exposed to the outside of the chamber 1. A portion of the cylindrical electrode 10 exposed to the outside of the chamber 1 is covered by a housing 12, as shown in FIG. The space inside the chamber 1 is kept airtight by the housing 12. The portion of the cylindrical electrode 10 located inside the chamber 1, that is, the periphery of the side wall is covered with the shield 13.

  The shield 13 is a fan-shaped square tube coaxial with the cylindrical electrode 10 and is larger than the cylindrical electrode 10. The shield 13 is connected to the chamber 1. Specifically, the shield 13 stands upright from the edge of the opening 1 a of the chamber 1, extends toward the inside of the chamber 1, and has a lower end located at the same height as the opening 11 of the cylindrical electrode 10. Since the shield 13 functions as a cathode similarly to the chamber 1, it is preferable that the shield 13 be made of a conductive metal member having low electric resistance. The shield 13 may be formed integrally with the chamber 1 or may be attached to the chamber 1 by using a fixture or the like.

  The shield 13 is provided to stably generate plasma in the cylindrical electrode 10. Each side wall of the shield 13 is provided so as to extend substantially parallel to each side wall of the cylindrical electrode 10 via a predetermined gap d. If the gap d is too large, the capacitance decreases or plasma generated in the cylindrical electrode 10 enters the gap d. Therefore, it is desirable that the gap d be as small as possible. However, if the gap d is too small, the capacitance between the cylindrical electrode 10 and the shield 13 increases, which is not preferable. The size of the gap d may be appropriately set according to the capacitance required for generating plasma, and may be, for example, 7 mm. Although FIG. 3 shows only two side walls extending in the radial direction of the shield 13 and the cylindrical electrode 10, the radius between the two side walls extending in the circumferential direction of the shield 13 and the cylindrical electrode 10 is also small. A gap d having the same size as the side wall surface in the direction is provided.

  Further, a process gas introducing unit 16 is connected to the cylindrical electrode 10, and a process gas is introduced into the cylindrical electrode 10 from an external process gas supply source via the process gas introducing unit 16. The process gas can be appropriately changed depending on the purpose of the film processing. For example, when etching is performed, an inert gas such as argon can be used as an etching gas. When performing the oxidation treatment or the post-oxidation treatment, oxygen can be used. In the case of performing the nitriding treatment, nitrogen can be used.

  An RF power supply 15 for applying a high-frequency voltage is connected to the cylindrical electrode 10. On the output side of the RF power supply 15, a matching box 21 as a matching circuit is connected in series. RF power supply 15 is also connected to chamber 1. When a voltage is applied from the RF power supply 15, the cylindrical electrode 10 acts as an anode, and the chamber 1, the shield 13, and the turntable 3 act as a cathode. The matching box 21 stabilizes the plasma discharge by matching the impedance on the input side and the impedance on the output side. The chamber 1 and the turntable 3 are grounded. The shield 13 connected to the chamber 1 is also grounded. The RF power supply 15 and the process gas introduction unit 16 are both connected to the cylindrical electrode 10 through a through hole provided in the housing 12.

When an oxygen gas, which is a process gas, is introduced into the cylindrical electrode 10 from the process gas inlet 16 and a high-frequency voltage is applied to the cylindrical electrode 10 from the RF power supply 15, the oxygen gas is turned into plasma, and electrons, ions, radicals, etc. Occurs. When the oxygen gas is turned into plasma, the temperature inside the cylindrical electrode 10 becomes high. As described above, since the cylindrical electrode 10 tends to be larger and thinner, it may be bent or deformed by heat. As described above, since the gap d between the cylindrical electrode 10 and the shield 13 is small, when the cylindrical electrode 10 is deformed, the cylindrical electrode 10 may come into contact with the shield 13.

  In the embodiment of the present invention, the spacer 30 is provided in the gap d between the cylindrical electrode 10 and the shield 13. Even if the cylindrical electrode 10 is deformed, the spacer 30 suppresses the movement of the cylindrical electrode 10, so that the contact between the cylindrical electrode 10 and the shield 13 is prevented. FIGS. 4 to 6 show enlarged views of the spacer. The spacer 30 has a rectangular parallelepiped block shape. In order to maintain insulation between the anode and the cathode, the spacer 30 is preferably made of an insulating material. The spacer 30 may be made of PTFE similarly to the insulating member 22.

  The spacer 30 has an upper surface and a lower surface that are parallel to each other and faces the upper surface and the bottom surface of the chamber 1, and further has four side surfaces 30a, 30b, 30c, and 30d that connect the upper surface and the lower surface. A bolt hole 31 is provided so as to penetrate a side surface 30 a facing the cylindrical electrode 10 and a side surface 30 b facing the shield 13. The bolt hole 31 is large enough to receive the head of the bolt 32 on the cylindrical electrode 10 side, but has a diameter reduced on the shield 13 side and has a size that allows only the shaft of the bolt 32 to pass through. In the illustrated example, two bolt holes 31 are provided in parallel, but the number of bolt holes 31 and the position of the bolt holes 31 are not limited to the illustrated example, and can be appropriately designed. As shown in FIG. 6, the spacer 30 is fixed to the shield 13 by a bolt 32 passed through a bolt hole 31. The bolt 32 is preferably made of an insulating material such as PEEK or PTFE.

The size of the spacer 30 can be determined as appropriate, but it is desirable that the spacer 30 made of an insulating material be small in size so as not to greatly affect the capacitance between the anode and the cathode. For example, the area of the side surface 30 a facing the cylindrical electrode 10 and the side surface 30 b facing the shield 13 may be about 1 to 3 cm ² .

  The width of the side surfaces 30c and 30d, which are orthogonal to the side surfaces 30a and 30b and connect the side surfaces 30a and 30b, is equal to or slightly smaller than the gap d between the cylindrical electrode 10 and the shield 13. It is preferable to fit into the gap d between the shaped electrodes 10. For example, if the gap d is 7 mm, the width of the side surfaces 30c and 30d may be 6 mm.

  The side surface 30 a facing the cylindrical electrode 10 has a chamfered corner located on the opening 1 a side of the chamber 1, and is provided with an inclined portion 33 inclined toward the shield 13. The inclination angle can be set as appropriate, but may be, for example, 30 ° with respect to the side surface a. When attaching the spacer 30, the spacer 30 is attached to the shield 13 with bolts 32 with the cylindrical electrode 10 removed from the opening 1 a of the chamber 1. Thereafter, the cylindrical electrode 10 is fitted through the opening 1a. As described above, since the dimensions of the spacer 30 are fitted in the gap d, the presence of the inclined portion 33 allows the cylindrical electrode 10 to be inserted smoothly.

  In the example of FIG. 3, two spacers 30 are respectively installed in the gap d between the two sidewall surfaces of the rectangular cylindrical shield 13 and the cylindrical electrode 10 along the radial direction, that is, the opposing gap d. I have. By disposing the two spacers 30 in the opposing gap d, the gap d can be stably maintained. The two spacers 30 are provided near the lower end of the cylindrical electrode 10, respectively. It is considered that the cylindrical electrode 10 is more likely to deform near the open lower end than near the upper end attached to the chamber 1. By installing the spacer 30 near the lower end, it is possible to prevent the vicinity of the lower end of the cylindrical electrode 10 that is easily deformed from coming into contact with the shield 13.

  However, the example in FIG. 3 is merely an example, and the number and positions of the spacers 30 are not limited thereto. Even when the cylindrical electrode 10 is deformed, contact can be prevented by maintaining the gap d between the shield 13 and the cylindrical electrode 10, and the increase in capacitance by the spacer 30 affects the control in the matching box 21. The installation position and the number of installations can be set as appropriate within a range not provided.

  For example, as shown in FIG. 7, the spacer 30 may be provided not only near the lower end but also near the upper end, near the middle between the upper end and the lower end, so that the gap d can be stably maintained as a whole. . Of course, it is not necessary to arrange at all three positions, for example, may be installed only near the upper end or near the middle. The spacing between the spacers 30 may be equal. Alternatively, they may not be arranged at regular intervals, but may be installed, for example, more near the lower end.

  FIGS. 3 and 7 show examples in which the rectangular cylindrical shield 13 and the cylindrical electrode 10 are installed in the gap d between two side walls along the radial direction. It may be installed in the gap d between the two side wall surfaces. Of course, it may be installed in both the radial gap d and the circumferential gap d. Alternatively, the spacer 30 may be provided in one of the radial gaps d and one of the circumferential gaps d without being provided in both of the opposing gaps d.

  The plasma processing apparatus further includes a control unit 20. The control unit 20 includes an arithmetic processing device such as a PLC or a CPU. The control unit 20 controls the introduction and exhaust of the sputtering gas and the process gas into and from the chamber 1, controls the DC power supply 7 and the RF power supply 15, and controls the rotation speed of the turntable 3.

[Operation and Action]
The operation of the plasma processing apparatus according to the present embodiment and the operation of the spacer 30 will be described. An unprocessed work W is carried into the chamber 1 from the load lock chamber. The loaded work W is held by the holding section 3a of the turntable 3. The inside of the chamber 1 is evacuated by the exhaust unit 2 to be in a vacuum state. By driving the rotary table 3, the workpiece W is transported along the transport path P, and passes below the processing units 4a to 4g.

  In the film forming unit 4a, a sputtering gas is introduced from a sputtering gas introduction unit 8, and a DC voltage is applied from a DC power supply 7 to the sputtering source. The application of the DC voltage turns the sputter gas into plasma, generating ions. When the generated ions collide with the target 6, the material of the target 6 jumps out. The protruding material is deposited on the work W passing under the film forming unit 4a, so that a thin film is formed on the work W. In the other film forming units 4b, 4c, 4d, 4f, and 4g, film formation is performed in the same manner. However, it is not always necessary to form a film in all film forming units. As an example, here, a Si film is formed on the work W by DC sputtering.

  The work W on which the film formation has been performed in the film formation units 4a to 4d is continuously transported on the transport path P by the rotary table 3, and in the film processing unit 4e, a position immediately below the opening 11 of the cylindrical electrode 10, that is, Pass through the membrane processing position. As described above, in the present embodiment, an example in which post-oxidation is performed in the film processing unit 4e will be described. In the membrane processing unit 4e, an oxygen gas, which is a process gas, is introduced from the process gas introduction unit 16 to the cylindrical electrode 10, and a high-frequency voltage is applied to the cylindrical electrode 10 from the RF power supply 15. Oxygen gas is turned into plasma by application of a high-frequency voltage, and electrons, ions, radicals, and the like are generated. The plasma flows from the opening 11 of the cylindrical electrode 10 as the anode to the rotary table 3 as the cathode. When the ions in the plasma collide with the thin film of the work W passing under the opening 11, the thin film is post-oxidized.

  As described above, the matching box 21 is connected to the RF power supply 15. The matching box 21 matches the output-side impedance with the input-side impedance so that the current flowing to the cathode side has a maximum value, so that stable plasma discharge is performed. However, when the cylindrical electrode 10 is bent or deformed by the heat generated during the plasma processing and comes into contact with the shield 13, an abnormal discharge may occur.

  In the present embodiment, since the spacer 30 is provided in the gap d between the shield 13 and the cylindrical electrode 10, even if the cylindrical electrode 10 is deformed, the shield 13 can be prevented from contacting. Here, if the purpose is to prevent the cylindrical electrode 10 from coming into contact with the shield 13, as shown in FIG. 8, the flange 10 a at the upper end of the cylindrical electrode 10 and the periphery of the opening 1 a of the chamber 1 It is considered that the insulating member 22 interposed therebetween is expanded to cover the entire gap d between the cylindrical electrode 10 and the shield 13. However, since the insulating member 22 occupies the entire gap d between the cylindrical electrode 10 and the shield 13, the capacitance between the anode and the cathode greatly increases.

  The matching box 21 performs impedance control based on a predetermined capacitance between the anode and the cathode. In the case of replacing the insulating member 22 with the existing plasma processing apparatus, the insulating member 22 must be reset in the matching box 21 based on the increased capacitance value. It is complicated.

  Therefore, in the present embodiment, the block-shaped spacer 30 is provided in the gap d between the cylindrical electrode 10 and the shield 13 so as not to greatly affect the capacitance between the anode and the cathode. The spacer 30 is provided in a part of the gap d. Therefore, the rate of increase can be suppressed lower than that of the insulating member 22 of FIG. 8 occupying the entire gap d. Even if the capacitance is slightly increased by the spacer 30, it is not necessary to perform resetting in the matching box 21 within the allowable range of the control in the matching box 21. It is known that if the rate of increase in capacitance is less than about ± 1%, stable plasma can be maintained without resetting the matching box 21.

  Here, the capacitance between the case where the insulating member 22 covers the entire gap d between the cylindrical electrode 10 and the shield 13 shown in FIG. 8 and the case where the spacer 30 of the present embodiment is arranged are shown. Compare the rate of increase.

  In the configuration of FIG. 8, when the insulating member 22 is made of PTFE, the gap d is replaced by PTEF having a relative dielectric constant of 2.1, so that the capacitance is about 2 compared to the case where nothing is arranged in the gap d. And the rate of increase in capacitance is about 100%. That is, in the case of the configuration shown in FIG. 8, since the control range of the matching box 21 is exceeded, the matching box 21 needs to be reset.

ここで、ε₀は真空の誘電率であり、８．８５×１０^−１２[Ｆ／ｍ]である。ε_rは誘電体の比誘電率である。 In the configuration of the present embodiment in which the spacer 30 is arranged in the gap d, the increase rate R [%] of the capacitance can be obtained as follows.
When a distance between plates is k [m] and an area of each parallel plate is S [m ² ], a capacitance C [F] of a capacitor composed of an anode and a cathode of a parallel plate is expressed by the following formula ( 1).

Here, ε ₀ is a vacuum dielectric constant, and is 8.85 × 10 ⁻¹² [F / m]. ε _r is the relative permittivity of the dielectric.

ここでＳ_pは、スペーサ３０の筒形電極１０と対向する面積[ｍ^２]である。式（１）の板間距離ｋ［ｍ］が、隙間ｄの大きさと対応する。Ｓ_p=６×１０−４[ｍ^２]＝６[ｃｍ^２]、ｄ＝７×１０^−３[ｍ]＝７[ｍｍ]を上記の式（２）に代入すると、Ｃ_pの値は、８．３５×１０^−１３[Ｆ]となる。 When the spacer 30 of the present embodiment is made of PTFE, ε _r is 2.1. The amount of increase C _{p of the} capacitance per spacer 30 may be obtained by subtracting the capacitance of the space where one of the spacers 30 is replaced from the capacitance of one of the spacers 30. ).

Here, _Sp is the area [m ² ] of the spacer 30 facing the cylindrical electrode 10. The plate-to-plate distance k [m] in Expression (1) corresponds to the size of the gap d. Substituting S _p = 6 × 10 −4 [m ² ] = 6 [cm ² ] and d = 7 × 10 ⁻³ [m] = 7 [mm] into the above equation (2), the value of C _p becomes , 8.35 × 10 ⁻¹³ [F].

ここで、ｎはスペーサ３０の設置個数である。スペーサ３０の設置個数を例えば９個とした場合、式（３）に、Ｃ₀＝７．６×１０−１０[Ｆ]、ｎ＝９を代入すると、増加率Ｒ＝０．９９[％]程度となる。 The increase rate R [%] of the capacitance due to the use of the spacer 30 is obtained by the following equation (3), where C ₀ [F] is the capacitance of the cylindrical electrode 10 without the spacer 30. be able to.

Here, n is the number of spacers 30 installed. Assuming that the number of spacers 30 to be installed is, for example, nine, if C ₀ = 7.6 × 10 −10 [F] and n = 9 are substituted into the equation (3), the increase rate R = 0.99 [%] About.

  That is, even if nine spacers 30 are provided, the rate of increase in capacitance is suppressed to less than 1% as compared with the case where no spacers 30 are provided, so that the control in the matching box 21 is affected. Therefore, stable plasma can be maintained without resetting.

[effect]
As described above, the plasma processing apparatus according to the present embodiment has the lower end that is one end where the opening 11 is provided, and the upper end that is the other end closed, and the process gas is introduced thereinto, and the voltage is applied. A cylindrical electrode 10 for converting the process gas into a plasma by performing the process, and a chamber 1 which is a vacuum vessel having an opening 1a, the upper end of which is attached to the opening 1a of the chamber 1 via an insulating member 22. 10 extends inside the chamber 1. The plasma processing apparatus also includes a rotary table 3 that is a transport unit that transports a workpiece W to be processed by a process gas below the opening 11 of the cylindrical electrode 10, and a cylindrical electrode that extends inside the vacuum vessel. The shield 13 covers the gap 10 through the gap d, and the spacer 30 is provided in a part of the gap d between the cylindrical electrode 10 and the shield 13 and made of an insulating material.

  In the film processing, the temperature rises significantly due to the generation of plasma, so that the cylindrical electrode 10 may be deformed by heat and come into contact with the shield 13. By arranging the spacer 30 in the gap d between the side wall of the cylindrical electrode 10 and the shield 13, the contact between the cylindrical electrode 10 and the shield 13 can be prevented, and the film processing can be performed stably. In addition, since the spacer 30 is provided not in the entire gap d but in a part thereof, the capacitance between the anode and the cathode is not significantly affected. Therefore, even when the spacer 30 is attached to an existing plasma processing apparatus, It is not necessary to reset the matching box 21 and the convenience is high.

  The spacer 30 may have a block shape. Thereby, it is easy to insert into the narrow gap d between the side wall of the cylindrical electrode 10 and the shield 13, and mounting becomes easy.

The spacer 30 may have a side surface 30a facing the cylindrical electrode 10 and a side surface 30b facing the shield 13 having an area of 1 to 3 cm ² . By reducing the size of the spacer 30, a change in the capacitance between the anode and the cathode can be reduced. Accordingly, even when the spacer 30 is attached to the existing plasma processing apparatus, it is not necessary to reset the matching box 21 and the convenience is high.

  The spacer 30 may have an inclined portion 33 inclined toward the shield 13 at a corner of the side surface 30 a located on the side of the opening 1 a of the chamber 1. Since the gap d between the cylindrical electrode 10 and the shield 13 is small, if the cylindrical electrode 10 is inserted from the opening 1a of the chamber 1 after the spacer 30 is installed, the cylindrical electrode 10 is easily caught by the spacer 30. Here, since the corner of the spacer 30 is inclined, it is possible to prevent the spacer 30 from being caught and to smoothly insert the cylindrical electrode 10. Thereby, the assembling efficiency can be improved.

  The spacer 30 may be fixed to the shield 13 with a bolt 32 made of an insulating material. By forming the bolt 32 for fixing the spacer 30 from an insulating material, insulation between the anode and the cathode can be maintained.

  The spacer 30 may be arranged near the lower end of the cylindrical electrode 10 provided with the opening 11. By arranging the spacer 30 near the lower end of the easily deformable cylindrical electrode 10, contact with the shield 13 can be effectively prevented.

  The spacer 30 may be installed near the lower end, near the upper end, or near the middle between the lower end and the upper end of the cylindrical electrode 10 provided with the opening 11. By arranging the spacers 30 in a dispersed manner, the gap d between the cylindrical electrode 10 and the shield 13 can be stably maintained as a whole.

  The cylindrical electrode 10 and the shield 13 have a rectangular cylindrical shape, and the spacer 30 may be provided in the gap d between the cylindrical electrode 10 and the shield 13 facing each other. By disposing the two spacers 30 in the opposing gap d, the gap d can be stably maintained.

[Other Embodiments]
(1) The present invention is not limited to the above embodiment. For example, in the above-described embodiment, post-oxidation is performed in the film processing, but etching or nitriding may be performed. In the case of an etching process, an argon gas is preferably introduced into the film processing unit 4e, and in the case of a nitriding process, a nitrogen gas is preferably introduced into the film processing unit 4e.

(2) The shape of the rotary table 3 and the chamber 1 accommodating each processing unit, and the type and arrangement of the processing units are not limited to specific ones, but can be appropriately changed according to the type of the work W and the installation environment.

(3) Although the embodiment of the present invention and the modification of each unit have been described above, the embodiment and the modification of each unit are presented as examples, and are not intended to limit the scope of the invention. . These novel embodiments described above can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims.

1 chamber (vacuum vessel)
1a Opening
2 Exhaust section
3 Rotary table (transport section)
3a Holder
3b Rotary axis
4a, 4b, 4c, 4d, 4f, 4g Processing unit (film formation unit)
4e Processing unit (membrane processing unit)
5 Load lock section
6 Target
7 DC power supply
8 Sputter gas inlet

9 Partition wall
10 cylindrical electrode
10a flange
11 Opening
12 Housing
13 Shield
15 RF power supply
16 Process gas inlet
20 control unit
21 Matching box
22 Insulating material
30 Spacer
30a, 30b, 30c, 30d side
31 bolt hole
32 volts
33 Inclined part
P transport path
W Work
d gap

Claims (8)

A cylindrical electrode that has one end provided with an opening and the other end closed, a process gas is introduced therein, and a voltage is applied to convert the process gas into a plasma,
A vacuum vessel having an opening, wherein the cylindrical electrode attached to the opening at the other end via an insulating member extends therein;
A transport unit that transports the workpiece to be processed by the process gas below an opening of the cylindrical electrode,
A shield connected to the vacuum vessel and covering the cylindrical electrode extending inside the vacuum vessel via a gap,
A spacer formed of an insulating material and installed in a part of a gap between the cylindrical electrode and the shield,
A plasma processing apparatus comprising:   The plasma processing apparatus according to claim 1, wherein the spacer has a block shape. 3. The plasma processing apparatus according to claim 2, wherein the spacer has a surface facing the cylindrical electrode and a surface facing the shield having an area of 1 to 3 cm ^{2. 4} .   The plasma according to claim 2, wherein the spacer has an inclined portion inclined toward the shield at a corner of the surface facing the cylindrical electrode, the corner being located on the opening side of the vacuum vessel. Processing equipment.   The plasma processing apparatus according to claim 1, wherein the spacer is fixed to the shield with a bolt made of an insulating material.   The plasma processing apparatus according to claim 1, wherein the spacer is provided near one end of the cylindrical electrode.   The plasma processing according to any one of claims 1 to 5, wherein the spacer is provided near one end, near the other end, and near the middle between the one end and the other end of the cylindrical electrode. apparatus.   The said cylindrical electrode and the said shield are square cylindrical, The said spacer is each installed in the opposing space | interval of the said cylindrical electrode and the said shield, The Claims any one of Claims 1-7 characterized by the above-mentioned. The plasma processing apparatus as described in the above.

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