TW201724919A - Plasma processing apparatus which can stabilize a plasma discharge even when a workpiece including an insulator is processed - Google Patents

Abstract

This invention provides a plasma processing device which can stabilize a plasma discharge even when a workpiece including an insulator is processed. The plasma processing apparatus comprises a cylindrical electrode (10) having an opening (11) at one end thereof and into which a process gas is introduced, an RF power supply (15) for applying a voltage to the cylindrical electrode (10), a rotary table (3) serving as a conveying unit for conveying a workpiece (W) circularly and at the same time allowing the workpiece to pass through the opening (11) of the cylindrical electrode imposed with voltage, and an electronic induction member (17) disposed between the opening (11) and the rotary table (3).

Description

Plasma processing device

The present invention relates to a plasma processing apparatus.

In a manufacturing process of various products such as a semiconductor device, a liquid crystal display, or an optical disk, an optical film may be formed on a work such as a wafer or a glass substrate. Wait for the film. The film can be produced by forming a film of a metal or the like on a workpiece, and repeatedly performing a film treatment such as etching, oxidation, or nitridation on the formed film.

Film formation and film processing can be carried out by various methods, and as one of them, there is a method of using plasma. At the time of film formation, an inert gas is introduced into a vacuum vessel in which a target is placed, and a DC voltage is applied. The ion of the plasma-inert inert gas collides with the target, and the material that has been knocked out from the target is deposited on the workpiece to form a film. In the film processing, a process gas is introduced into a vacuum vessel in which electrodes are disposed, and a high-frequency voltage is applied to the electrodes. The plasma treatment is carried out by causing ions of the plasma-formed process gas to collide with the film on the workpiece.

There is a plasma processing apparatus in which a rotary table is mounted inside a vacuum container, and a plurality of units for film formation and a unit for film processing are disposed along a circumferential direction above the rotary table so as to be able to Such film formation and film treatment are continuously performed (for example, refer to Patent Document 1). An optical film or the like is formed by holding the workpiece on a rotating platform and passing it through the film forming unit and the film processing unit directly under the film forming unit.

In the plasma processing apparatus using the rotary table, as the membrane processing unit, a cylindrical electrode having an open end and having an opening at the lower end (hereinafter referred to as a "cylinder electrode") may be used. In such a membrane processing unit, the cylindrical electrode functions as an anode, and the rotating platform located below the opening of the cylindrical electrode functions as a cathode. A process gas is introduced into the interior of the cylindrical electrode and a high frequency voltage is applied to cause plasma generation. The electrons contained in the generated plasma flow into the rotating platform side as a cathode. The workpiece held by the rotating platform is passed under the opening of the cylindrical electrode, whereby ions contained in the plasma collide with the workpiece to perform film processing.

Prior art literature

Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2002-256428

[Problems to be solved by the invention]

Insulation is sometimes included in the workpiece conveyed by the rotating platform. If the workpiece containing the insulator is under the cylindrical electrode, the cathode will contain the insulator. As a result, it is difficult for the electrons of the plasma to flow into the cathode side, and the plasma becomes unstable, so that the film treatment may not be properly performed.

Here, a radio frequency (RF) power source that applies a high-frequency voltage to the cylindrical electrode is connected to the cylindrical electrode and the vacuum container via a matching box. Even in a state where the workpiece is positioned below the cylindrical electrode, the plasma can be stabilized by matching the impedance of the input side and the output side by the matching device.

However, if you want to improve processing efficiency, you should place as many workpieces as possible on the rotating platform. If the gap between the workpieces is narrowed, the cathode will frequently switch between the state without the insulator and the state containing the insulator. At this time, the impedance adjustment by the matcher may not keep up. As a result, the plasma discharge may become unstable, thereby affecting the quality of the film treatment.

An object of the present invention is to provide a plasma processing apparatus capable of stabilizing plasma discharge even when processing a workpiece including an insulator in order to solve the above problems, thereby eliminating the workpiece The state is improved to improve processing efficiency.

[Technical means to solve the problem]

In order to achieve the above object, a plasma processing apparatus according to the present invention includes a cylindrical electrode having an opening at one end and a process gas introduced therein, and a transfer unit that circulates and transports the workpiece while passing the voltage to which the voltage is applied. The underside of the opening of the cylindrical electrode; and an electron inducing member disposed between the opening and the conveying portion.

The electron inducing member may be a ring-shaped member having a hole portion at the center.

The electron inducing member may be a plate-shaped member that crosses a central portion of the opening in a direction orthogonal to a conveying direction of the conveying portion.

The conveying portion may include a rotating platform disposed in the vacuum container to hold the workpiece to be cyclically conveyed, and the cylindrical electrode is disposed to hold the workpiece of the rotating platform Above the position, the plasma processing apparatus further includes a support member that supports the electron inducing member between the opening portion and the rotating platform.

The support member may include an outer support member that is erected from a bottom portion near an outer edge of the vacuum vessel and extends directly below the cylindrical electrode, in the rotating platform and the cylindrical shape The electron inducing members are supported between the electrodes.

The plasma processing apparatus may further include a pillar, the pillar is erected inside the vacuum vessel, and a front end portion penetrates a center of the rotating platform, and the rotating platform is rotatably supported by the pillar via a bearing. The support member includes an inner support member that is mounted to the post and extends directly below the cylindrical electrode to support the electron induction between the rotating platform and the cylindrical electrode member.

The electron inducing member may be connected to a front end of the cylindrical electrode via an insulating material.

The electron inducing member may cover an area of 50% to 85% of the opening.

The electron inducing member may include an electroconductive member and an etch resist, an antioxidant, or a nitriding agent applied to the conductive member.

[Effects of the Invention]

By disposing the electron inducing member between the opening of the cylindrical electrode and the conveying portion of the workpiece, it is possible to induce electrons generated by the plasma to be induced by electrons without being affected by the properties of the workpiece conveyed by the conveying unit or the conveying state. The member is capable of stabilizing the plasma discharge. By stabilizing the plasma discharge, ions, radicals, and the like generated by the plasma stably reach the workpiece. As a result, it is possible to provide a plasma processing apparatus which can improve the processing efficiency and can provide a product of stable quality.

[composition]

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. An exhaust portion 2 is provided in the chamber 1, and the inside of the chamber 1 can be evacuated to a vacuum. That is, the chamber 1 functions as a vacuum container. A hollow rotating shaft 3b passes through the bottom of the chamber 1 and is erected inside the chamber 1. A substantially circular rotating platform 3 is mounted on the rotating shaft 3b. A drive mechanism (not shown) is coupled to the rotating shaft 3b. The rotary table 3 is rotated about the rotary shaft 3b by the drive of the drive mechanism. Inside the hollow rotating shaft 3b, a stationary strut 3c is disposed. The pillar 3c is fixed to a base (not shown) provided outside the chamber 1, and is erected inside the chamber 1 through the bottom of the chamber 1. An opening is provided in the center of the rotary table 3. The pillar 3c penetrates the opening of the rotary table 3, and the front end is located between the upper surface of the rotary table 3 and the upper surface of the chamber 1. In addition, the front end of the pillar 3c may also contact the upper surface of the chamber 1. A ball bearing 3d is disposed between the opening of the rotary table 3 and the support 3c. That is, the rotary table 3 is rotatably supported by the support 3c via the ball bearing 3d.

Since the chamber 1, the rotary table 3, and the rotating shaft 3b function as a cathode in the plasma processing apparatus, a conductive metal member having a small electric resistance can be included. The rotating platform 3 can be, for example, a metal such as aluminum, stainless steel or copper. Further, as the rotating platform 3, a person who is sprayed with alumina on the surface of a stainless steel plate member may be used. Although alumina is an insulator, in the case of high-frequency plasma, plasma can be formed as long as the thickness of the alumina is in a range in which the matching device can achieve impedance matching. When the aluminum oxide is sprayed in this manner, the rotary stage 3 is hardly etched by the plasma, and particles adhering to the etching can be prevented from adhering to the workpiece W or the inner wall of the chamber 1, and the like, and particles can be reduced.

On the upper surface of the rotary table 3, a plurality of holding portions 3a for holding the workpiece W are provided. The plurality of holding portions 3a are provided at equal intervals along the circumferential direction of the rotary table 3. The workpiece W held by the holding portion 3a is moved in the circumferential direction of the rotary table 3 by the rotation of the rotary table 3. In other words, on the surface of the rotary table 3, a transport path (hereinafter referred to as "transport path P") which is a circular movement locus of the workpiece W is formed. The holding portion 3a can be, for example, a tray on which the workpiece W is placed. When the tray is, for example, of a type capable of placing two workpieces W, as shown in FIG. 3, the gap between the two workpieces W placed on the same tray is smaller than the gap between the workpieces W placed on the other trays. narrow.

Hereinafter, when it is simply referred to as "circumferential direction", it means "the circumferential direction of the rotating platform 3", and when it is simply referred to as "radial direction", it means "the radial direction of the rotating platform 3". Further, in the present embodiment, a flat plate-shaped substrate is used as an example of the workpiece W, but the type, shape, and material of the workpiece W subjected to the plasma treatment are not limited to those specific. For example, a curved substrate having a concave portion or a convex portion at the center may also be used. Further, a substrate including a conductive material such as metal or carbon, a substrate including an insulator such as glass or rubber, and a substrate including a semiconductor such as germanium may be used.

Above the rotating platform 3, a unit (hereinafter referred to as a "processing unit") that performs processing in each step in the plasma processing apparatus is provided. Each of the processing units is disposed such that the transport path P of the workpiece W formed on the surface of the rotary table 3 is adjacent to each other with a predetermined interval therebetween. The processing of each step is performed by passing the workpiece W held by the holding portion 3a under each processing unit.

In the example of FIG. 1 , seven processing units 4 a to 4 g are disposed along the transport path P on the rotary table 3 . In the present embodiment, the processing unit 4a, the processing unit 4b, the processing unit 4c, the processing unit 4d, the processing unit 4f, and the processing unit 4g are film forming units that perform a film forming process on the workpiece W. The processing unit 4e is a film processing unit that processes a film formed on the workpiece W by the film forming unit. In the present embodiment, the film forming unit is described as a unit that performs sputtering. Further, the film processing unit 4e will be described as a unit for performing post-oxidation. In addition, the term "post-oxidation" refers to a process of oxidizing a metal film by introducing oxygen ions or the like generated by a plasma into a metal film formed by a film formation unit. Between the processing unit 4a and the processing unit 4g, there is provided a load lock portion 5 that carries the unprocessed workpiece W from the outside into the interior of the chamber 1, and the processed portion is processed. The workpiece W is carried out to the outside of the chamber 1. Further, in the present embodiment, the conveying direction of the workpiece W is the direction from the position of the processing unit 4a toward the processing unit 4g in the clockwise direction of FIG. Of course, this is only an example, and the conveyance direction, the type of the processing unit, the arrangement order, and the number are not limited to a specific one, and can be appropriately determined.

FIG. 2 shows a configuration example of the processing unit 4a as a film forming unit. The other film forming unit 4b, the film forming unit 4c, the film forming unit 4d, the film forming unit 4f, and the film forming unit 4g may be configured in the same manner as the film forming unit 4a, but other configurations may be applied. As shown in FIG. 2, the film forming unit 4a is provided with a target 6 attached to the inner upper surface of the chamber 1 as a sputtering source. The target 6 is a plate-like member including a material deposited on the workpiece W. The target 6 is disposed at a position facing the workpiece W when the workpiece W passes under the film forming unit 4a. A direct current (DC) power source 7 that applies a direct current voltage to the target 6 is connected to the target 6. Further, a sputtering gas introduction portion 8 for introducing a sputtering gas into the inside of the chamber 1 is provided in the vicinity of a portion of the upper surface of the chamber 1 on which the target 6 is attached. As the sputtering gas, for example, an inert gas such as argon can be used. Around the target 6, a partition wall 9 for reducing the outflow of the plasma is provided. Further, as for the power source, a well-known power source such as a DC pulse power source or an RF power source can be applied.

2 and 3 show a configuration example of the film processing unit 4e. The film processing unit 4e includes an electrode (hereinafter referred to as a "tubular electrode") 10 which is provided on the inner upper surface of the chamber 1 and is formed in a cylindrical shape. The cylindrical electrode 10 has a rectangular tubular shape, and has an opening portion 11 at one end and a closed end at the other end. The cylindrical electrode 10 is disposed in such a manner as to penetrate a through hole provided in the upper surface of the chamber 1, and an end portion on the side of the opening portion 11 is located inside the chamber 1, and a closed end portion is located outside the chamber 1. The cylindrical electrode 10 is supported by the periphery of the through hole of the chamber 1 via an insulating material. The opening portion 11 of the cylindrical electrode 10 is disposed at a position opposed to the conveyance path P formed on the rotary table 3. In other words, the rotating platform 3 serves as a conveying unit and circulates and conveys the workpiece W while passing it directly below the opening portion 11. Further, the position directly below the opening portion 11 serves as a passing position of the workpiece W.

As shown in FIG. 1, the cylindrical electrode 10 has a fan shape that expands in diameter from the center side in the radial direction of the rotary table 3 as viewed from above. The sector shape referred to herein refers to the shape of the portion of the fan sector. The opening portion 11 of the cylindrical electrode 10 is also fan-shaped. The speed at which the workpiece W held on the rotary table 3 passes under the opening portion 11 is slower toward the center side in the radial direction of the rotary table 3, and the faster toward the outer side. Therefore, when the opening portion 11 has a simple rectangular shape or a square shape, the time between the center side and the outer side in the radial direction and the workpiece W passing directly under the opening portion 11 is different. By expanding the diameter of the opening 11 from the center side in the radial direction to the outside, the time during which the workpiece W passes through the opening 11 can be fixed, and the plasma processing to be described later can be made uniform. However, if the time difference of passage is such that it does not cause a problem in the product, it may be a rectangle or a square.

As described above, the cylindrical electrode 10 penetrates the through hole of the chamber 1, and a part thereof is exposed to the outside of the chamber 1. The portion of the cylindrical electrode 10 exposed to the outside of the chamber 1 is covered by an outer shield 12 as shown in FIG. The internal space of the chamber 1 is kept airtight by the outer shroud 12. The portion of the cylindrical electrode 10 located inside the chamber 1 is covered by the inner shroud 13.

The inner shroud 13 has a rectangular tubular shape coaxial with the cylindrical electrode 10 and is supported on the upper surface of the inside of the chamber 1. The respective side faces of the inner shroud 13 are provided substantially in parallel with the respective side faces of the cylindrical electrode 10. The lower end of the inner shroud 13 is the same position as the opening portion 11 of the cylindrical electrode 10 in the height direction, but at the lower end of the inner shroud 13, a flange extending in parallel with the upper surface of the rotary table 3 is provided (flange ) 14. The plasma generated in the inside of the cylindrical electrode 10 is prevented from flowing out to the outside of the inner shroud 13 by the flange 14. The workpiece W conveyed by the rotary table 3 is carried directly under the opening portion 11 of the cylindrical electrode 10 through the gap between the rotary table 3 and the flange 14, and passes again through the gap between the rotary table 3 and the flange 14. Further, it is carried out from directly below the opening 11 of the cylindrical electrode 10.

On the cylindrical electrode 10, an RF power source 15 for applying a high-frequency voltage is connected. On the output side of the RF power source 15, a matching unit 21 as a matching circuit is connected in series. The RF power source 15 is also connected to the chamber 1. The cylindrical electrode 10 functions as an anode, and the rotating platform 3 that is erected from the chamber 1 functions as a cathode. The matching unit 21 stabilizes the discharge of the plasma by matching the impedances on the input side and the output side. In addition, the chamber 1 or the rotary table 3 is grounded. The inner shroud 13 with the flange 14 is also grounded.

Further, the process gas introduction portion 16 is connected to the cylindrical electrode 10, and the process gas is introduced into the cylindrical electrode 10 from the external process gas supply portion via the process gas introduction portion 16. The process gas can be appropriately changed depending on the purpose of the film treatment. For example, an inert gas such as argon may be used as the etching gas when etching is performed. When the oxidation treatment or the post oxidation treatment is performed, oxygen can be used. When nitriding treatment is performed, nitrogen can be used. Both the RF power source 15 and the process gas introduction portion 16 are connected to the cylindrical electrode 10 via a through hole provided in the outer shroud 12.

An electron inducing member 17 is provided between the opening portion 11 of the cylindrical electrode 10 and the rotating platform 3. FIG. 4 shows an example of the electron inducing member 17. The electron inducing member 17 is an annular member having a hole portion 17a at the center. The outer shape of the electron inducing member 17 and the shape of the center hole portion 17a are each a fan shape similar to the opening portion 11 of the cylindrical electrode 10. The outer shape of the electron inducing member 17 is slightly smaller than the opening portion 11. When the electron inducing member 17 is provided between the opening portion 11 of the cylindrical electrode 10 and the rotating platform 3, the electron inducing member 17 is disposed at the outer edge portion of the periphery of the opening portion 11 so as to be substantially covered. The shape of the edge. However, since the outer shape of the electron inducing member 17 is slightly smaller than the opening portion 11, as shown in FIG. 4, a gap is left between the cylindrical electrode 10 and the electron inducing member 17.

Further, the electron inducing member 17 only needs to cover the periphery of the opening portion 11 so as to cover the periphery thereof. Therefore, the outer shape of the electron inducing member 17 may be larger than the opening portion 11. At this time, the electron inducing member 17 is in a form of covering the outer edge portion of the opening portion 11 without a gap.

The electron inducing member 17 functions as a cathode, that is, an auxiliary electrode of the rotating platform 3. That is, a plasma discharge is generated between the cylindrical electrode 10 and the rotating platform 3 functioning as a cathode, so that plasma is formed in the vicinity of the cathode, that is, directly above the rotating platform 3. Further, the workpiece W is processed by passing the workpiece W under the plasma thus generated. Further, when the workpiece W is insulative and the portion of the rotary table 3 disposed opposite to the cylindrical electrode 10 is covered by the insulating workpiece W, the plasma discharge may become unstable and may not be properly processed. . Therefore, even in this case, the electron inducing member 17 can induce electrons contained in the plasma generated inside the cylindrical electrode 10 so that the plasma finally reaches the workpiece W passing under the hole portion 17a. . The radial width of the hole portion 17a may be greater than the radial width of the workpiece W so that the plasma reaches the entire workpiece W. Since the entire workpiece can be plasma-treated by moving the workpiece W in the conveyance direction, the circumferential width of the hole portion 17a can be made smaller than the circumferential width of the workpiece W.

When the electron inducing member 17 is disposed between the opening portion 11 of the cylindrical electrode 10 and the rotating platform 3, the electron inducing member 17 can cover an area of 50% to 85% of the opening portion 11. If it is less than 50%, the plasma may not be sufficiently induced by the electron inducing member 17. When it exceeds 85%, the area covered by the opening portion 11 increases, and the plasma hardly reaches the workpiece W instead.

As shown in FIG. 4, when the outer shape of the electron inducing member 17 is slightly smaller than the opening portion 11, the area of the electron inducing member 17 can be set to 50% to 85% with respect to the area of the opening portion 11. When the outer shape of the electron inducing member 17 is larger than the opening portion 11, the area of the portion located below the opening portion 11 can be set to 50% to 85% with respect to the area of the opening portion 11.

The electron inducing member 17 may include a conductive material. Moreover, a material having a low electrical resistance can also be used. As such a material, aluminum, stainless steel, or copper can be cited. It may also comprise the same material as the rotating platform 3 and may also comprise different materials. Further, in the same manner as in the case of the above-described rotating platform 3, the electron inducing member 17 is, for example, a member in which alumina is used as an insulator to the surface of a plate-shaped member of stainless steel, and the effect of reducing particles can be obtained. Preferably. Since the electron inducing member 17 is located between the cylindrical electrode 10 and the rotating platform 3, it is subjected to plasma treatment similarly to the workpiece W. The electrical characteristics are changed by the plasma treatment, and if the force for inducing the electrons of the plasma is weak, it must be replaced. Therefore, it is also possible to apply an anti-etching agent, an antioxidant or a nitriding agent depending on the content of the plasma treatment. Thereby, it is possible to suppress variations in electrical characteristics and to reduce the frequency of replacement.

As shown in FIG. 2, the electron inducing member 17 is fixed by being placed between the opening portion 11 of the cylindrical electrode 10 and the rotating platform 3 via the supporting member. The support member includes an outer support member 18 and an inner support member 19. The outer side support member 18 fixes the outer side of the electron inducing member 17 in the radial direction from the outer side of the rotary table 3. The inner side support member 19 extends from the center portion of the rotary table 3, and fixes the inner side in the radial direction of the electron inducing member 17.

The outer support member 18 includes a support bar 18a and a mounting metal member 18b provided at the front end of the support bar 18a. The support rod 18a has an inverted L shape, and the vertical portion of the L word is located between the outer circumference of the rotary table 3 and the outer peripheral wall of the chamber 1, and is erected from the bottom of the chamber 1. The vertical portion of the L-shape of the support rod 18a extends upward until the horizontal portion of the L-shape is located on the upper side of the upper surface of the rotary table 3, that is, the surface on which the workpiece W is placed. The horizontal portion of the L-shape is located directly above the face of the rotary table 3, and its front end extends toward the center of the rotary table 3 and passes under the flange 14 and the inner shroud 13 to reach directly below the opening portion 11. At its front end, as shown in Fig. 4, a mounting metal member 18b is provided.

The mounting metal member 18b is not limited to a specific configuration as long as the electron inducing member 17 can be fixed. FIG. 4 shows an example in which the mounting metal fitting 18b is a bolt and a nut. At this time, bolt holes may be provided in the electron inducing member 17. Alternatively, the mounting metal piece 18b may be a clip that clamps the electron inducing member 17 by the elastic force of the spring.

The inner support member 19 includes a support rod 19a and a mounting metal member 19b provided at the front end of the support rod 19a. The support rod 19a is attached to a distal end portion of the strut 3c that penetrates the opening of the center of the rotary table 3 and protrudes from the upper surface of the rotary table 3 by fixing a metal member such as a bolt. The support rod 19a extends toward the position of the film processing unit 4e outside the radial direction of the rotary table 3. The position at which the tip end of the support rod 19a reaches can be set to the vicinity of the center of the circumferential width of the cylindrical electrode 10. The support rod 19a passes under the flange 14 and the inner shroud 13 to reach directly below the opening portion 11.

Similarly to the outer support member 18, the attachment metal fitting 19b at the tip end of the support rod 19a is not limited to a specific configuration as long as the electron induction member 17 can be fixed. Further, the inner side support member 19 and the outer side support member 18 may be formed as mounting metal members 19b having different configurations. For example, the inner support member 19 may be a jig, and the outer support member 18 may be a bolt and a nut. When the electronic induction member 17 is replaced, for example, a jack is used to lift up the upper surface portion of the chamber 1, and the body is introduced from the outside of the chamber 1 to perform replacement work. The inner support member 19 located on the center side of the chamber 1 is difficult to perform replacement work. Therefore, the inner support member 19 can also be a jig that can be fixed by inserting the electron inducing member 17 to facilitate the mounting work. Further, the outer support member 18, which is relatively easy to work, can also be provided as a bolt and a nut so as to be securely fixed. Of course, if the electron inducing member 17 can be fixed by only one of the inner side support member 19 or the outer side support member 18, only one of them may be provided.

The plasma processing apparatus further includes a control unit 20. The control unit 20 includes an arithmetic processing unit such as a programmable logic controller (PLC) or a central processing unit (CPU). The control unit 20 performs control such as control related to introduction and exhaust of the sputtering gas and the process gas into the chamber 1, control of the DC power source 7 and the RF power source 15, and control of the rotation speed of the rotating platform 3. Further, the power source such as the DC power source 7 or the RF power source 15 may be configured to be independent of the basic configuration of the plasma processing apparatus, and may be connected to an existing power source or a separately prepared power source.

[action]

The operation of the plasma processing apparatus of the present embodiment and the operation of the electron inducing member 17 will be described. The unprocessed workpiece W is carried into the chamber 1 from the load lock chamber. The workpiece W that is carried in is held by the holding portion 3a of the rotary table 3. The inside of the chamber 1 is exhausted by the exhaust unit 2 to be in a vacuum state. By driving the rotary table 3, the workpiece W is circulated and conveyed along the conveyance path P so as to repeatedly pass under each of the processing units 4a to 4g. In other words, as will be described later, the workpiece W is formed in a period in which the workpiece W is cyclically moved along the circular conveyance path P and passes through the respective processing units 4a to 4g several times.

In the film forming unit 4a, a sputtering gas is introduced from the sputtering gas introduction unit 8, and a DC voltage is applied from the DC power source 7 to the sputtering source. The sputtering gas is plasmad by the application of a direct current voltage to generate ions. When the generated ions collide with the target 6, the material of the target 6 flies out. The flying material is deposited on the workpiece W passing under the film forming unit 4a, thereby forming a film on the workpiece W. Film formation is performed in the same manner in the other film forming unit 4b, film forming unit 4c, film forming unit 4d, film forming unit 4f, and film forming unit 4g. However, it is not always necessary to use all of the film forming units to form a film. As an example, here, the Si film is formed by DC sputtering on the workpiece W.

The workpiece W formed by the film forming unit 4a to the film forming unit 4d is transported by the rotating platform 3 on the transport path P, and passes through the opening portion 11 of the cylindrical electrode 10 in the film processing unit 4e. Position, ie the film 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, oxygen as a process gas is introduced into the cylindrical electrode 10 from the process gas introduction portion 16, and a high-frequency voltage is applied from the RF power source 15 to the cylindrical electrode 10. Oxygen is plasmad by the application of a high-frequency voltage to generate electrons, ions, radicals, and the like. The plasma flows from the opening portion 11 of the cylindrical electrode 10 as an anode to the rotating platform 3 as a cathode. The film is subjected to post oxidation by colliding ions in the plasma to the film on the workpiece W passing under the opening portion 11.

Here, when the workpiece W conveyed by the rotary table 3 is located below the opening portion 11, the workpiece W itself functions as a cathode. When the workpiece W containing the insulator is used, if the insulator is included in the cathode, the input side impedance will become high. As a result, the flow of the plasma toward the cathode side is hindered, and the plasma discharge may become unstable.

As described above, the matcher 21 is connected to the RF power source 15. Even in a state where the workpiece W including the insulator is located below the opening portion 11, the plasma can be made to flow toward the cathode side as long as the output side impedance is matched to the input side impedance by the matching unit 21.

However, as shown in FIG. 3, there is a case where the gap between the workpieces W is extremely narrow, or the size of the gap is changed. In this state, the cathode frequently switches between the state in which the insulator is not contained and the state in which the insulator is contained, and the impedance on the input side also frequently changes. The matching process in the matcher 21 may not keep up with frequent changes.

In the present embodiment, the electron inducing member 17 is disposed between the opening portion 11 of the cylindrical electrode 10 and the rotating platform 3. The electron inducing member 17 functions as an auxiliary electrode of the cathode. That is, the electron inducing member 17 is disposed at a position intermediate between the cylindrical electrode 10 and the rotating stage 3 and the workpiece W, and induces plasma generated inside the cylindrical electrode 10 to the side of the rotating platform 3. The induced plasma passes through the hole portion 17a of the electron inducing member 17, and reaches the workpiece W passing under the opening portion 11. Further, the outer edge portion of the opening portion 11 is covered by the electron inducing member 17, so that the area of the workpiece W facing the cylindrical electrode 10, that is, the area of the workpiece W to which the electrons flow is reduced. Therefore, the influence of the insulator of the workpiece W on the input side impedance is also reduced, which contributes to stabilization of the plasma discharge. As a result, even if the workpiece W including the insulator is conveyed in a state where the matching process in the matching device 21 cannot be followed, the stable plasma treatment can be performed without being affected by the properties of the workpiece W.

In addition, the electron inducing member 17 is only assisted by the rotating platform 3 as an electrode, and the cylindrical electrode 10 and the rotating platform 3 are respectively electrodes. It is assumed that the electron inducing member 17 is a cathode, the rotating platform 3 is an insulator, and no discharge occurs between the cylindrical electrode 10 and the rotating platform 3, that is, when the rotating platform 3 does not function as an electrode, post-oxidation or the like is based on the reason described below. The plasma treatment will be weak.

(a) Since plasma is formed between the cylindrical electrode 10 and the electron inducing member 17, the plasma is farther from the rotating platform 3 than when the rotating platform 3 functions as an electrode. Therefore, it is difficult for the plasma to reach the workpiece W.

(b) The rotating platform 3 is no longer subject to self bias, so the force of attracting ions toward the rotating platform 3 is weak.

[test]

In order to verify that the electron inducing member 17 covers the relationship between the area of the opening portion 11 of the cylindrical electrode 10 and the plasma discharge, post-oxidation treatment is performed in the film processing unit 4e of the plasma processing apparatus. The film processing unit 4e has the same configuration as that of the above embodiment, but the electron inducing member 17 is not provided in the test. The test conditions are as follows.

·Workpiece···Insulating resin substrate

·Rotating platform speed ···60 rpm

·Process gas:···O2 300 sccm 3 Pa

· High frequency power: 13.56 MHz 300 W

The post-oxidation is performed a plurality of times by changing the number of the insulating substrates which have been formed by the film forming unit and formed the Si film by the rotary stage 3. Further, the reflected wave power in each test was measured. By changing the number of insulating substrates, the ratio of the conductive material of the rotating platform 3 in the cathode to the insulating material of the workpiece W is changed. As a result, the relationship between the area of the opening portion 11 of the cylindrical electrode 10 and the reflected wave power can be verified by the electron inducing member 17 by the relationship between the ratio of the conductive material and the insulator to the reflected wave power. In addition, DC sputtering of the Si film is performed simultaneously with post-oxidation. Moreover, the conditions are the same as the well-known conditions, and therefore are omitted.

Table 1 shows the test results. In the state in which the insulating substrate was three sheets, the area of the conductive material in the cathode was 43%. At this time, the reflected wave power was 60 W with respect to the traveling wave power of 300 W, and a return loss of 20% was generated. On the other hand, when the number of sheets of the insulating substrate is small, that is, when the area of the conductive material in the cathode is increased, the reflected wave power is reduced, and the return loss is also reduced. In an example in which the insulating substrate is two sheets and the area of the conductive material is 62%, the reflected wave power is 20 W, and in the example where the insulating substrate is one piece and the area of the conductive material is 81%, the reflected wave power is changed. It is 10 W.

Table 1

That is, as long as the electron inducing member 17 covers 50% of the area of the opening portion 11, the influence of the insulator on the impedance can be reduced, and an effective plasma treatment can be performed. In a state where the insulating substrate is in a state of zero, that is, in a state where the electron inducing member 17 covers 100% of the opening portion 11, the reflected wave power is 0 W, but the plasma certainly cannot reach the workpiece W. In order to ensure the path of the plasma toward the workpiece W, the upper limit of the area of the electron inducing member 17 with respect to the opening portion 11 can be set to 85%.

[effect]

(1) The plasma processing apparatus according to the present embodiment includes a cylindrical electrode 10 having an opening 11 at one end and a process gas introduced therein, and a rotating platform 3 as a conveying unit that circulates and transports the workpiece W while passing it The lower portion of the opening 11 of the cylindrical electrode 10 to which the voltage is applied; and the electron inducing member 17 are disposed between the opening 11 and the rotating platform 3.

By disposing the electron inducing member 17 between the opening portion 11 of the cylindrical electrode 10 and the rotating platform 3, it is possible to induce electrons generated by the plasma to the electron inducing member 17 without being affected by the properties of the workpiece W or the transport state. Thereby, the plasma discharge can be stabilized. By stabilizing the plasma discharge, ions or radicals generated by the plasma stably reach the workpiece W. As a result, it is possible to provide a plasma processing apparatus which can improve the processing efficiency without being affected by the properties of the workpiece W or the conveyance state, and can stabilize the quality of the film formed on the workpiece W.

(2) The electron inducing member 17 is an annular member having a hole portion 17a at the center. By arranging the electron inducing member 17 between the opening portion 11 and the rotating platform 3, the area of the workpiece W facing the cylindrical electrode 10, that is, the area of the workpiece W to which the electrons flow is reduced. Therefore, even in the case where the workpiece W contains an insulator, the influence on the input side impedance is reduced, which contributes to stabilization of the plasma discharge. Further, the plasma induced by the electron inducing member 17 can reach the workpiece W via the hole portion 17a.

(3) The electron inducing member 17 may cover an area of 50% to 85% of the opening portion 11. If it is less than 50%, electrons generated by the plasma may not be sufficiently induced by the electron inducing member 17. When it exceeds 85%, the area covered by the opening portion 11 increases, and it is difficult to reach the workpiece W by ions or radicals generated by the plasma. By making the area of the opening portion 11 of the electron inducing member 17 an area of 50% to 85% of the opening portion 11, it is possible to sufficiently induce electrons generated by the plasma, and ions or radicals generated by the plasma are also The workpiece W can be fully reached. Therefore, it is possible to perform a good workpiece process which can stabilize the discharge and ensure the processing efficiency of the workpiece W.

(4) The rotary table 3 is disposed inside the chamber 1 as a vacuum container, and holds the workpiece W on the surface. The cylindrical electrode 10 is disposed above the holding position of the workpiece W of the rotary table 3. The plasma processing apparatus is installed in the chamber 1 as a supporting member that supports the electron-inducing member 17 between the opening portion 11 of the cylindrical electrode 10 and the rotating platform 3, and may include the inner supporting member 19 and the outer supporting member 18. The electron inducing member 17 can be fixed on the rotating platform by using the supporting member.

(5) The outer support member 18 is erected from the bottom portion near the outer edge of the chamber 1 and extends directly below the cylindrical electrode 10, and supports the electron inducing member 17 between the rotary table 3 and the cylindrical electrode 10. By being disposed near the outer edge of the chamber 1, the work becomes easy when the electron inducing member 17 is replaced.

(6) Further includes a pillar 3c which is erected inside the chamber 1, and the front end portion penetrates the center of the rotary table 3. The rotary table 3 is rotatably supported by the support 3c via a ball bearing 3d as a bearing. The inner support member 19 is attached to the stay 3c, extends directly below the cylindrical electrode 10, and supports the electron inducing member 17 between the rotary table 3 and the cylindrical electrode 10. The electron inducing member 17 can be fixed on the rotating platform 3 by attaching the inner supporting member 19 to the stationary stay 3c supporting the rotary table 3.

(7) The electron inducing member 17 may also include a conductive member and an etch resist, an antioxidant, or a nitriding agent applied around the conductive member. The electron inducing member 17 disposed under the cylindrical electrode 10 is also subjected to plasma treatment in the same manner as the workpiece W, and must be replaced if the characteristics change. By coating with an etch resist, an antioxidant, or a nitriding agent in combination with the form of plasma treatment, it is possible to suppress variations in characteristics and reduce the frequency of replacement.

[Other embodiments]

(1) The present invention is not limited to the embodiment. For example, in the above-described embodiment, the shape of the electron inducing member 17 is an annular shape that covers the outer edge of the opening portion 11 of the cylindrical electrode 10. However, as long as the electrons of the plasma can be induced to the workpiece W, it is not limited to The shape. For example, as shown in FIG. 5, the electron inducing member 17 may be a rectangular plate member 170. The width of the plate-like member 170 in the circumferential direction may be smaller than the circumferential width of the opening portion 11. Further, the width of the plate-shaped member 170 in the circumferential direction may be increased in diameter from the radial center side toward the outer side in accordance with the sector-shaped opening portion 11. The plate member 170 is provided to cross the center of the opening portion 11 in the radial direction. The radial direction is a direction orthogonal to the conveying direction of the workpiece W by the rotary table 3. With such a configuration, the plate-like member 170 covers the central portion in the radial direction of the opening portion 11, and both end portions of the center portion are open. The plasma generated inside the cylindrical electrode 10 is induced by the plate-like member 170 and reaches the workpiece W through both end portions of the opening portion 11. Thereby, similarly to the above-described embodiment, stable plasma treatment can be performed without being affected by the properties of the workpiece W. In addition, the width of the plate-like member 170 in the radial direction may have a width close to the radial direction width of the opening portion 11 so that plasma can be uniformly induced.

(2) Further, in the embodiment, the outer support member 18 and the inner support member 19 are used to mount the electron inducing member 17 into the chamber 1, but the electron inducing member 17 may be passed through the insulator as shown in FIG. It is attached to the front end of the cylindrical electrode 10. The electron inducing member 17 is grounded by being electrically connected to the upper surface portion of the chamber 1 or the inner shroud 13. Since the cylindrical electrode 10 and the electron inducing member 17 are not electrically connected by being connected via the insulating material, the electron inducing member 17 can function as an auxiliary electrode on the cathode side. By attaching to the cylindrical electrode 10, it is not necessary to separately prepare a support member, so the number of parts can be reduced.

(3) In the above embodiment, the configuration in which the outer support member 18 and the inner support member 19 of the electron inducing member 17 are attached to the bottom of the chamber 1 has been described. However, the present invention is not limited to the bottom portion, and may be attached to the chamber, for example. The upper surface or wall of 1.

(4) The trajectory of the cyclic transport is not limited to the circumference. It is widely included in the form of a non-joint-shaped transport path for cyclic transport. For example, it may be a rectangle or an ellipse, and may also include a path of a crank or a meandering. The jointless conveying path may include, for example, a conveyor or the like.

(5) A bias voltage can also be applied to the rotating platform 3. Moreover, a magnet can also be disposed below the rotating platform 3. By these measures, the electrons will be trapped, so that it is easier to form a plasma on the rotating platform 3.

1‧‧‧ chamber
2‧‧‧Exhaust Department
3‧‧‧Rotating platform
3a‧‧‧ Keeping Department
3b‧‧‧Rotary axis
3c‧‧‧ pillar
3d‧‧‧Ball bearings
4a, 4b, 4c, 4d, 4f, 4g‧‧‧ processing unit (film forming unit)
4e‧‧‧Processing unit (membrane processing unit)
5‧‧‧Load Interlocking Department
6‧‧‧ Target
7‧‧‧DC power supply
8‧‧‧Sputter gas introduction
9‧‧‧ partition wall
10‧‧‧Cylinder electrode
11‧‧‧ openings
12‧‧‧External shield
13‧‧‧Interior shield
14‧‧‧Flange
15‧‧‧RF power supply
16‧‧‧Process Gas Introduction Department
17‧‧‧Electronic induction components
17a‧‧‧孔部
18‧‧‧Outer support members
19‧‧‧Inside support member
18a, 19a‧‧‧ support rod
18b, 19b‧‧‧Installation of metal parts
20‧‧‧Control Department
21‧‧‧matcher
22‧‧‧Insulation
170‧‧‧ Plate-like members (electron-inducing members)
P‧‧‧Transportation
W‧‧‧Workpiece

FIG. 1 is a plan view schematically showing a configuration of a plasma processing apparatus according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line A-A of Fig. 1; Fig. 3 is a cross-sectional view taken along line B-B of Fig. 1 and is a view of the film processing unit viewed from the center of the rotary table. 4 is a plan view of a film processing unit. Fig. 5 is a plan view showing a film processing unit of a plasma processing apparatus according to another embodiment of the present invention. Fig. 6 is a view of the plasma processing apparatus according to another embodiment of the present invention, which is viewed from the center of the rotating platform.

4e‧‧‧Processing unit (membrane processing unit)

10‧‧‧Cylinder electrode

11‧‧‧ openings

17‧‧‧Electronic induction components

17a‧‧‧孔部

18a, 19a‧‧‧ support rod

18b, 19b‧‧‧Installation of metal parts

W‧‧‧Workpiece

Claims (9)

A plasma processing apparatus comprising: a cylindrical electrode having an opening at one end and a process gas introduced therein; and a transfer portion that circulates and transports the workpiece while passing the workpiece through the cylindrical electrode to which a voltage is applied Below the opening; and an electron inducing member disposed between the opening and the conveying portion. The plasma processing apparatus according to claim 1, wherein the electron inducing member is an annular member having a hole portion at a center. The plasma processing apparatus according to claim 1, wherein the electron inducing member is a plate-shaped member, and the plate-shaped member crosses the opening and is positively conveyed to the conveying unit The center of the direction of the intersection. The plasma processing apparatus according to any one of claims 1 to 3, wherein the conveying unit includes a rotating platform, the rotating platform is disposed in a vacuum container, and the workpiece is held to Circulatingly transporting, the cylindrical electrode is disposed above a holding position of the workpiece of the rotating platform, the plasma processing device further includes a supporting member, the supporting member is in the opening portion and the rotating The electron inducing members are supported between the platforms. The plasma processing apparatus of claim 4, wherein the support member includes an outer support member that is erected from a bottom portion near an outer edge of the vacuum container and extends to the barrel Directly below the shaped electrode, the electron inducing member is supported between the rotating platform and the cylindrical electrode. The plasma processing apparatus of claim 4 or 5, further comprising: a pillar erected inside the vacuum vessel, a front end portion penetrating a center of the rotating platform, the rotating platform passing through a bearing Rotatablely supported on the post, the support member includes an inner support member mounted to the post, extending directly below the cylindrical electrode, at the rotating platform and the barrel The electron inducing members are supported between the shaped electrodes. The plasma processing apparatus according to claim 1 or 2, wherein the electron inducing member is connected to a front end of the cylindrical electrode via an insulating material. The plasma processing apparatus according to any one of the preceding claims, wherein the electron inducing member covers an area of 50% to 85% of the opening. The plasma processing apparatus according to any one of the preceding claims, wherein the electron inducing member includes a conductive member and an etch resist and an antioxidant applied to the conductive member, Or anti-nitriding agent.