JP7573576B2 - Plasma Processing Equipment - Google Patents

Description

The present invention relates to a plasma processing device.

In the manufacturing process of various products such as semiconductor devices, liquid crystal displays, and optical disks, thin films such as optical films may be formed on workpieces such as wafers and glass substrates. Thin films can be created by forming a metal film or other film on the workpiece, or by performing film processing such as etching, oxidation, or nitridation on the formed film.

Film formation or film processing can be performed in a variety of ways, one of which is a method using plasma. In film formation, an inert gas is introduced into a chamber in which a target is placed, and a direct current voltage is applied. Ions of the inert gas that has been converted into plasma are collided with the target, and the material that is knocked out of the target is deposited on the workpiece to form a film. In film processing, a process gas is introduced into a chamber in which an electrode is placed, and a high-frequency voltage is applied to the electrode. Film processing is performed by colliding active species such as ions and radicals from the process gas that has been converted into plasma with a film on the workpiece.

In order to perform such film formation and film processing consecutively, there is a plasma processing apparatus in which a rotating table, which is a rotating body, is installed inside one chamber, and multiple film formation units and film processing units are arranged in the circumferential direction above the turntable (see, for example, Patent Document 1). In this way, an optical film, etc. is formed by holding and transporting the workpiece on the turntable and passing it directly under the film formation unit and the film processing unit.

In plasma processing equipment using a rotary table, a cylindrical electrode (hereinafter referred to as a "cylindrical electrode") with a closed upper end and an opening at the lower end may be used as the film processing unit. When using a cylindrical electrode, an opening is provided at the top of the chamber, and the upper end of the cylindrical electrode is attached to this opening via an insulator. The sidewall of the cylindrical electrode extends into the interior of the chamber, and the opening at the lower end faces the rotary table with a small gap between them. The chamber is grounded, the cylindrical electrode functions as the anode, and the chamber and the rotary table 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 a workpiece held on the rotary table under the opening of the cylindrical electrode, active species such as ions and radicals generated by the plasma collide with the workpiece, performing film processing.

Patent No. 4428873 Patent No. 3586198

In recent years, as the workpieces to be processed have become larger and there is a demand for improved processing efficiency, there is a trend toward expanding the areas in which plasma is generated to form and process films. However, when generating plasma by applying a voltage to a cylindrical electrode, it can be difficult to generate high-density plasma over a wide area.

A plasma processing apparatus has been developed that can generate a relatively wide-area, high-density plasma to perform film processing on large workpieces (see, for example, Patent Document 2). In such plasma processing apparatus, an antenna is placed outside the chamber, with a window member such as a dielectric between it and the gas space into which the process gas is introduced. Then, by applying a high-frequency voltage to the antenna, plasma is generated in the gas space by inductive coupling, and film processing is performed.

In the plasma processing apparatus using the above-mentioned turntable, a film processing section using inductively coupled plasma is used as the film processing unit. In this case, in order to suppress the increase in weight of the window of the dielectric material, it is possible to make the width of the window of the dielectric material, etc., constant in the circumferential direction of the turntable. Accordingly, it is also possible to form the range in the circumferential direction of the turntable where the film processing is performed, that is, the width of the processing area, parallel to the direction along the radial direction of the turntable. However, there is a difference in the speed of passing through the processing area of the surface of the turntable between the inner and outer periphery of the turntable. In other words, the passing speed within the same distance is faster on the outer periphery of the turntable and slower on the inner periphery. When the width of the processing area is formed parallel to the direction along the radial direction of the turntable as described above, the surface of the turntable passes through the processing area in a shorter time on the outer periphery side than on the inner periphery side. Therefore, the film processing rate after processing for a certain time is lower on the outer periphery side and higher on the inner periphery side.

For example, when a niobium or silicon film formed in the film forming section is oxidized or nitrided as a film treatment to produce a compound film, the degree of oxidation or nitridation of the niobium or silicon film will differ significantly between the inner and outer circumferences of the rotating table. This makes it difficult to uniformly treat the entire workpiece or to change the degree of treatment at a desired position on the workpiece.

This problem also occurs, for example, when plasma processing is performed on semiconductor wafers or other workpieces arranged in a row in the circumferential direction on a rotating table. Furthermore, the problem becomes even more pronounced when plasma processing is performed on multiple wafers arranged in the radial direction as well, from the standpoint of improving processing efficiency. Specifically, when the radius of the rotating table exceeds 1.0 m and the width of the processing area in the radial direction of the rotating table becomes as large as 0.5 m, the difference in processing rate between the inner and outer periphery becomes very large.

The present invention aims to provide a plasma processing device that can perform the desired plasma processing on a workpiece circulated by a rotating body according to the position on the surface of the rotating body where the passing speed differs.

In order to achieve the above object, the plasma processing apparatus of the present invention comprises a vacuum vessel capable of creating a vacuum inside, a transport section provided within the vacuum vessel and having a rotor which rotates with a work mounted thereon, and which circulates and transports the work along a circumferential transport path by rotating the rotor, a cylindrical section having an opening at one end extending in a direction toward the transport path inside the vacuum vessel, a window section provided in the cylindrical section for separating a gas space into which a process gas is introduced between the inside of the cylindrical section and the rotor from the outside of the gas space, and a gas supply port provided at a plurality of locations along an inner wall of the cylindrical section for supplying a process gas to the gas space. and an antenna that is arranged outside the gas space near the window and that, when power is applied, generates inductively coupled plasma in the process gas in the gas space for plasma processing of the workpiece passing through the transport path, wherein the supply unit supplies two types of process gas from the supply ports at locations where the surface of the rotating body passes through a processing area where the plasma processing is performed at different times, and has an adjustment unit that individually adjusts the supply amount per unit time of each type of process gas supplied to each supply port in accordance with the passing time.

The gas supply unit may have a plurality of supply ports provided corresponding to a plurality of locations to which the process gas is supplied, and a dispersion plate arranged at intervals opposite the supply ports to disperse the process gas supplied from the supply ports and allow it to flow into the gas space.

The flow path of the process gas between the dispersion plate and the supply port may be closed on the rotating body side and communicate with the gas space on the window side.

The adjustment unit may adjust the amount of process gas supplied from each supply port depending on the position in a direction intersecting the transport path.

The apparatus may have a film-forming unit that is provided at a position facing the workpiece being circulated along the transport path and that deposits a film-forming material on the workpiece by sputtering to form a film, and may perform film processing using the inductively coupled plasma on the film of film-forming material deposited on the workpiece by the film-forming unit.

The supply port corresponds to an area where the film forming unit forms a film, and is provided in an annular film forming area along the transport path, and is also provided outside the film forming area, and the supply port provided outside the film forming area may be excluded from the adjustment of the supply amount of the process gas by the adjustment unit.

The supply ports may be disposed at positions facing each other across the gas space and in a direction along the transport path.

The adjustment unit may adjust the amount of process gas supplied from each gas inlet depending on the film thickness to be formed on the workpiece and the passage time.

According to the present invention, the desired plasma treatment can be performed on the workpieces circulated by the rotating body according to the positions on the surface of the rotating body where the passing speed differs.

1 is a transparent perspective view of a plasma processing apparatus according to an embodiment; 1 is a perspective plan view of a plasma processing apparatus according to an embodiment; 3 is a cross-sectional view taken along line AA in FIG. 2. 3 is a cross-sectional view taken along line BB in FIG. 2. FIG. 5 is an enlarged view showing a detail of part A in FIG. 4 . FIG. 2 is an exploded perspective view showing the processing unit according to the embodiment. FIG. 2 is a perspective plan view showing a processing unit according to the embodiment. FIG. 2 is a schematic diagram showing a flow path of a process gas. FIG. 2 is a perspective view showing an antenna according to an embodiment. FIG. 2 is a block diagram showing a configuration of a control device according to the embodiment. 1 is a graph showing test results of comparative examples and examples.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention (hereinafter, referred to as the present
[overview]
The plasma processing apparatus 100 shown in FIG. 1 is an apparatus for forming a compound film on the surface of each workpiece W by utilizing plasma. That is, in the plasma processing apparatus 100, as shown in FIG. 1 to FIG. 3, when the rotor 31 rotates, the workpiece W on the tray 34 held by the holder 33 moves along a circular trajectory. By this movement, the workpiece W repeatedly passes a position facing the film forming section 40A, 40B or 40C. At each pass, the particles of the targets 41A to 41C are attached to the surface of the workpiece W by sputtering. In addition, the workpiece W repeatedly passes a position facing the film processing section 50A or 50B. At each pass, the particles attached to the surface of the workpiece W are combined with a substance in the introduced process gas G2 to form a compound film.

[composition]
Such a plasma processing apparatus 100 includes a vacuum vessel 20, a transfer section 30, film forming sections 40A, 40B, and 40C, film processing sections 50A and 50B, a load lock section 60, and a control device 70, as shown in FIGS.

[Vacuum vessel]
The vacuum vessel 20 is a vessel capable of creating a vacuum inside, a so-called chamber. A vacuum chamber 21 is formed inside the vacuum vessel 20. The vacuum chamber 21 is a cylindrical sealed space surrounded by a ceiling 20a, an inner bottom surface 20b, and an inner peripheral surface 20c inside the vacuum vessel 20. The vacuum chamber 21 is airtight and can be made into a vacuum by reducing the pressure. The ceiling 20a of the vacuum vessel 20 is configured to be openable and closable.

Reactive gas G is introduced into a specified area inside the vacuum chamber 21. The reactive gas G includes sputtering gas G1 for film formation and process gas G2 for film processing (see FIG. 3). In the following description, when there is no need to distinguish between sputtering gas G1 and process gas G2, they may be referred to as reactive gas G. Sputtering gas G1 is a gas for depositing the material of targets 41A-41C on the surface of the workpiece W by colliding ions generated by plasma generated by application of electric power with targets 41A-41C. For example, an inert gas such as argon gas can be used as sputtering gas G1.

The process gas G2 is a gas for forming a compound film by penetrating active species generated by the plasma generated by inductive coupling into the film deposited on the surface of the workpiece W. Hereinafter, such a surface treatment using plasma and not using the targets 41A to 41C may be called reverse sputtering. The process gas G2 can be appropriately changed depending on the purpose of the treatment. For example, when oxynitriding a film, a mixed gas of oxygen _O2 and nitrogen _N2 is used.

As shown in FIG. 3, the vacuum vessel 20 has an exhaust port 22 and an inlet port 24. The exhaust port 22 is an opening for ensuring the flow of gas between the vacuum chamber 21 and the outside and for exhausting E. This exhaust port 22 is formed, for example, at the bottom of the vacuum vessel 20. An exhaust section 23 is connected to the exhaust port 22. The exhaust section 23 has piping and a pump, valve, etc. (not shown). The exhaust process by this exhaust section 23 reduces the pressure inside the vacuum chamber 21.

The inlet 24 is an opening for introducing the sputtering gas G1 into each of the film forming sections 40A, 40B, and 40C. The inlet 24 is provided, for example, in the upper part of the vacuum vessel 20. The gas supply section 25 is connected to the inlet 24. In addition to piping, the gas supply section 25 has a gas supply source of the reaction gas G, a pump, a valve, etc. (not shown). The gas supply section 25 introduces the sputtering gas G1 from the inlet 24 into the vacuum chamber 21. In addition, the upper part of the vacuum vessel 20 is provided with an opening 21a into which the film processing sections 50A and 50B are inserted, as described below.

[Transport section]
An overview of the transport unit 30 will be described. The transport unit 30 has a rotating body 31 provided in the vacuum vessel 20. The rotating body 31 carries the workpiece W. The transport unit 30 is a device that rotates the rotating body 31 to circulate the workpiece W along a circumferential transport path T. The circulatory transport means repeatedly moving the workpiece W around a circumferential trajectory. The transport path T is a trajectory along which the workpiece W or a tray 34 described later moves by the transport unit 30, and is a doughnut-shaped ring with a certain width. The transport unit 30 will be described in detail below.

The rotating body 31 is a circular plate-shaped rotating table. The rotating body 31 may be, for example, a plate-shaped member of stainless steel with aluminum oxide sprayed on its surface. Hereinafter, the term "circumferential direction" simply means the "circumferential direction of the rotating body 31", and the term "radial direction" simply means the "radial direction of the rotating body 31". In addition, in this embodiment, a flat substrate is used as an example of the workpiece W, but the type, shape, and material of the workpiece W to be subjected to plasma treatment are not limited to a specific one. For example, a curved substrate having a concave or convex part in the center may be used. In addition, a substrate containing a conductive material such as metal or carbon, a substrate containing an insulating material such as glass or rubber, or a substrate containing a semiconductor such as silicon may be used. In addition, the number of workpieces W to be subjected to plasma treatment is not limited to a specific number.

The conveying unit 30 has a motor 32 and a holding unit 33 in addition to the rotating body 31. The motor 32 is a driving source that applies a driving force to the rotating body 31 and rotates it around the center of the circle as an axis. The holding unit 33 is a component that holds the tray 34 conveyed by the conveying unit 30. On the surface of the rotating body 31, a plurality of holding units 33 are arranged at equal circumferential positions. The surface of the rotating body 31 in this embodiment is the surface that faces upward when the rotating body 31 is horizontal, that is, the top surface. For example, the area where each holding unit 33 holds the tray 34 is formed in a direction parallel to the tangent of the circle in the circumferential direction of the rotating body 31, and is provided at equal intervals in the circumferential direction. More specifically, the holding unit 33 is a groove, hole, protrusion, jig, holder, etc. that holds the tray 34, and can be configured by a mechanical chuck, an adhesive chuck, etc.

The tray 34 is a rectangular flat plate having a flat mounting surface on one side for mounting the workpiece W. The material of the tray 34 is preferably a material with high thermal conductivity, such as metal. In this embodiment, the material of the tray 34 is SUS. The material of the tray 34 may be, for example, ceramics or resin with good thermal conductivity, or a composite material thereof. The workpiece W may be mounted directly on the mounting surface of the tray 34, or indirectly via a frame having an adhesive sheet or the like. A single workpiece W may be mounted on each tray 34, or multiple workpieces W may be mounted.

In this embodiment, six holding sections 33 are provided, so six trays 34 are held on the rotating body 31 at 60° intervals. However, there may be only one holding section 33 or multiple holding sections 33. The rotating body 31 circulates and transports the trays 34 carrying the workpieces W, repeatedly passing through positions facing the film forming sections 40A, 40B, and 40C and the film processing sections 50A and 50B.

[Film forming section]
The film forming units 40A, 40B, and 40C are provided at positions facing the workpieces W circulated along the transport path T, and are processing units that deposit a film-forming material on the workpieces W by sputtering to form a film. Hereinafter, when there is no need to distinguish between the multiple film forming units 40A, 40B, and 40C, they will be described as film forming unit 40. As shown in FIG. 3, the film forming unit 40 has a sputtering source 4, a partition unit 44, and a power supply unit 6.

(Sputtering source)
The sputtering source 4 is a supply source of a film-forming material that is deposited by sputtering on the workpiece W to form a film. As shown in Fig. 2 and Fig. 3, the sputtering source 4 has targets 41A, 41B, and 41C, a backing plate 42, and an electrode 43. The targets 41A, 41B, and 41C are formed of a film-forming material that is deposited on the workpiece W to form a film, and are disposed at positions facing each other at a distance on the transport path T.

In this embodiment, the three targets 41A, 41B, and 41C are arranged at positions aligned on the vertices of a triangle in a plan view. The targets 41A, 41B, and 41C are arranged in this order from the side closer to the center of rotation of the rotating body 31 toward the outer periphery. Hereinafter, when the targets 41A, 41B, and 41C are not distinguished from each other, they will be described as target 41. The surface of the target 41 faces the workpiece W moved by the conveying unit 30 at a distance. Note that the area to which the film-forming material can be attached by the three targets 41A, 41B, and 41C is larger than the size of the tray 34 in the radial direction. In this way, the annular area along the conveying path T, which corresponds to the area where the film is formed by the film-forming unit 40, is the film-forming area F (shown by the dotted line in FIG. 2). The radial width of the film-forming area F is longer than the radial width of the tray 34. In this embodiment, the three targets 41A to 41C are arranged so that the film-forming material can be deposited without gaps across the entire radial width of the film-forming region F.

For example, niobium, silicon, etc. are used as the film-forming material. However, various materials can be used as long as they can be used to form a film by sputtering. The target 41 is, for example, cylindrical. However, it may be other shapes, such as an oval cylinder or a rectangular column.

The backing plate 42 is a member that holds each of the targets 41A, 41B, and 41C individually. The electrode 43 is a conductive member that applies power to each of the targets 41A, 41B, and 41C individually from outside the vacuum vessel 20. The power applied to each of the targets 41A, 41B, and 41C can be changed individually. The sputtering source 4 is appropriately equipped with magnets, cooling mechanisms, and the like as necessary.

(Dividing section)
The partition 44 is a member that separates the film-forming positions M2, M4, and M5 where the workpiece W is formed by the sputtering source 4, and the film-processing positions M1 and M3 where the film processing is performed. As shown in FIG. 2, the partition 44 is a rectangular wall plate arranged radially from the center of rotation of the rotating body 31 of the transport unit 30. For example, as shown in FIG. 1, the partition 44 is provided between the film processing unit 50A, the film-forming unit 40A, the film processing unit 50B, the film-forming unit 40B, and the film-forming unit 40C on the ceiling 20a of the vacuum chamber 21. The lower end of the partition 44 faces the rotating body 31 with a gap through which the workpiece W passes. The presence of the partition 44 can suppress the diffusion of the reaction gas G and the film-forming material at the film-forming positions M2, M4, and M5 into the vacuum chamber 21.

The horizontal range of the deposition positions M2, M4, and M5 is an area partitioned by a pair of partitions 44. The workpiece W, which is circulated and transported by the rotor 31, repeatedly passes through positions facing the target 41 at deposition positions M2, M4, and M5, causing the deposition material to be deposited as a film on the surface of the workpiece W. These deposition positions M2, M4, and M5 are the areas where most of the deposition takes place, but even in areas outside of these areas, some leakage of the deposition material occurs, so that does not mean that no film is deposited at all. In other words, the areas where the deposition takes place are slightly larger than each of the deposition positions M2, M4, and M5.

(Power supply section)
The power supply unit 6 is a component that applies power to the target 41. By applying power to the target 41 by the power supply unit 6, a plasmatized sputtering gas G1 is generated. Then, ions generated by the plasma collide with the target 41, and the film-forming material knocked out from the target can be deposited on the workpiece W. The power applied to each target 41A, 41B, 41C can be changed individually. In this embodiment, the power supply unit 6 is, for example, a DC power supply that applies a high voltage. In the case of a device that performs high-frequency sputtering, it can also be an RF power supply. In addition, the power supply unit 6 may be provided for each of the film-forming units 40A, 40B, 40C, or only one power supply unit 6 may be provided for the multiple film-forming units 40A, 40B, 40C. When only one power supply unit 6 is provided, the application of power is switched. The rotating body 31 has the same potential as the grounded vacuum vessel 20, and a potential difference is generated by applying a high voltage to the target 41 side.

By forming films simultaneously using the same film forming material, the multiple film forming units 40A, 40B, and 40C can increase the amount of film formed within a certain period of time, i.e., the film forming rate. In addition, by using different types of film forming materials for the film forming units 40A, 40B, and 40C, it is possible to form a film consisting of multiple layers of film forming materials.

In this embodiment, as shown in FIG. 2, three film forming units 40A, 40B, and 40C are arranged between the film processing units 50A and 50B in the transport direction of the transport path T. Film forming positions M2, M4, and M5 correspond to the three film forming units 40A, 40B, and 40C. Film processing positions M1 and M3 correspond to the two film processing units 50A and 50B.

[Film Processing Section]
The film processing sections 50A and 50B are processing sections that perform film processing on the material deposited on the workpiece W transported by the transport section 30. This film processing is reverse sputtering that does not use a target 41. Hereinafter, when there is no need to distinguish between the film processing sections 50A and 50B, they will be described as the film processing section 50. The film processing section 50 has a processing unit 5. An example of the configuration of this processing unit 5 will be described with reference to FIGS. 3 to 6.

As shown in Figs. 3 and 4, the processing unit 5 has a tube H, a window 52, a supply section 53, an adjustment section 54 (see Fig. 8), and an antenna 55. The tube H is a cylindrical component with an opening Ho at one end extending in a direction toward the transport path T inside the vacuum container 20. The tube H has a cylindrical body 51, a cooling section 56, and a dispersion section 57. Among these components that make up the tube H, the cylindrical body 51 will be described first, and the cooling section 56 and the dispersion section 57 will be described later. The cylindrical body 51 is a tube with a rounded rectangular shape in horizontal cross section. The rounded rectangular shape here refers to the shape of a track in track and field events. The track shape is a shape in which a pair of partial circles are opposed to each other at a distance with the convex sides facing each other in opposite directions, and both ends of each circle are connected by straight lines parallel to each other. The cylindrical body 51 is made of the same material as the rotating body 31. The cylindrical body 51 is inserted into the opening 21a provided in the ceiling 20a of the vacuum vessel 20 so that the opening 51a faces away from the rotating body 31. As a result, most of the side wall of the cylindrical body 51 is contained within the vacuum chamber 21. The cylindrical body 51 is arranged so that its long diameter direction is parallel to the radial direction of the rotating body 31. However, it does not have to be strictly parallel, and there may be some inclination. In addition, the processing area where the plasma processing, i.e., the film processing, is performed is a rounded rectangular shape similar to the opening 51a of the cylindrical body 51. In other words, the width of the processing area in the rotational direction is the same in the radial direction.

As shown in Figures 4 and 5, an inner flange 511 is formed around one end of the cylindrical body 51. The inner flange 511 is a thick portion that protrudes from the inner edge of one end of the cylindrical body 51 around the entire circumference so that a vertical cross section perpendicular to the outer circumference is L-shaped. The innermost edge of this inner flange 511 is a rounded rectangular opening 51a that is approximately similar to the cross section of the cylindrical body 51. The inner flange 511 has shelf surfaces 511a, 511b, and 511c that become lower as they go from the inner wall of the cylindrical body 51 to the opening 51a, forming a stepped shape.

As shown in Figures 7 and 8, the inner flange 511 is formed with a number of supply ports 512A-D, 512a-d. Hereinafter, when there is no need to distinguish between the supply ports 512A-D, 512a-d, they will be referred to as supply ports 512. As shown in Figures 4 and 5, the supply ports 512 are holes that supply the process gas G2 into the cylindrical body 51. Each supply port 512 penetrates from the shelf surface 511a to the opening 51a so as to be L-shaped as shown in Figure 5.

Here, when comparing the center side (inner circumference side) and the outer circumference side of the rotating body 31 of the workpiece W mounted on the rotating body 31, a difference occurs in the speed at which the workpiece W passes over a certain distance. That is, in this embodiment, the cylindrical body 51 is arranged so that the long diameter direction is parallel to the radial direction of the rotating body 31. Moreover, the straight portions of the opening 51a in which the multiple supply ports 512 are formed are parallel to each other in the radial direction. In this configuration, the time it takes for the workpiece W to pass over a certain distance at the bottom of the cylindrical body 51 is shorter on the outer circumference side than on the inner circumference side of the rotating body 31. For this reason, the multiple supply ports 512 are provided at multiple locations where the surface of the rotating body 31 passes through the processing area where the plasma processing is performed at different times. The direction in which the multiple supply ports 512 are arranged side by side intersects with the transport path T. Furthermore, the supply ports 512 are arranged at positions facing each other across the gas space R. The direction in which the supply ports 512 facing each other across the gas space R is arranged is along the transport path T.

8, the supply ports 512A-D are arranged at equal intervals along one inner wall in the longitudinal direction of the cylindrical body 51, i.e., in the direction of the long diameter. The supply ports 512a-d are arranged at equal intervals along the other inner wall in the longitudinal direction of the cylindrical body 51. The supply ports 512A-D are arranged in the order of supply port 512A, supply port 512B, supply port 512C, and supply port 512D from the inner circumference side to the outer circumference side. Similarly, the supply ports 512a-d are arranged in the order of supply port 512a, supply port 512b, supply port 512c, and supply port 512d. The supply ports 512A-D are arranged downstream of the transport path T, and the supply ports 512a-d are arranged upstream of the transport path T. Supply port 512A and supply port 512a, supply port 512B and supply port 512b, supply port 512C and supply port 512c, and supply port 512D and supply port 512d face each other on the downstream and upstream sides, respectively.

Furthermore, as shown in FIG. 4, an outer flange 51b is formed on the end of the cylindrical body 51 opposite the opening 51a. An O-ring 21b is disposed around the entire circumference between the bottom surface of the outer flange 51b and the top surface of the vacuum vessel 20, hermetically sealing the opening 21a.

The window portion 52 is provided in the cylindrical portion H and is a member that separates the gas space R into which the process gas G2 in the vacuum vessel 20 is introduced and the outside. In this embodiment, the window portion 52 is provided in the cylindrical body 51 that constitutes the cylindrical portion H. The gas space R is a space formed between the rotating body 31 and the inside of the cylindrical portion H in the film processing portion 50, through which the workpiece W circulated and transported by the rotating body 31 repeatedly passes. The window portion 52 is a flat plate of a dielectric material that fits inside the cylindrical body 51 and has a shape similar to the horizontal cross section of the cylindrical body 51. The window portion 52 is placed on an O-ring 21b that is fitted into a groove formed circumferentially on the shelf surface 511b, and hermetically seals the opening 51a. The window portion 52 may be a dielectric material such as alumina, or a semiconductor material such as silicon.

As shown in Figures 4, 6 and 8, the supply unit 53 supplies the process gas G2 to the gas space R. The supply unit 53 is a device that supplies the process gas G2 from multiple locations where the surface of the rotating body 31 passes through the processing area at different times. These multiple locations correspond to the locations of the supply ports 512 in the longitudinal direction of the cylindrical body 51. Specifically, the supply unit 53 has a process gas G2 supply source such as a cylinder (not shown) and pipes 53a, 53b, and 53c connected to the supply source. The process gas G2 is, for example, oxygen and nitrogen. The pipes 53a are a pair of paths from the respective process gas G2 supply sources. That is, the pipes 53a are composed of a path connected to the oxygen supply source and a path connected to the nitrogen supply source. Four sets of pipes 53a are provided corresponding to the locations of the supply ports 512. The pipes 53b are one path to which the pair of pipes 53a are connected. Each pipe 53b is connected to each of the supply ports 512A to D in one row. In addition, pipes 53c branching off from each pipe 53b are connected to the supply ports 512a-d of the other row.

The tips of the branched pipes 53c extend from the outer flange 51b side along the inner wall of the cylindrical body 51 to the opening 51a side, and are connected to the end of the supply port 512 on the shelf surface 511a side. Similarly, the pipe 53b is connected to the end of the supply port 512 on the shelf surface 511a side. As a result, the supply unit 53 supplies the process gas G2 to the gas space R from multiple locations where the workpiece W passes through at different speeds through the supply ports 512A-D and supply ports 512a-d arranged in parallel as described above. In other words, the supply ports 512A-D and supply ports 512a-d are provided corresponding to multiple locations to which the supply unit 53 supplies the process gas G2. In this embodiment, the innermost supply ports 512A, 512a and the outermost supply ports 512D, 512d are located outside the film formation region F.

8, the adjustment unit 54 adjusts the supply amount of the process gas G2 introduced from each supply port 512 depending on the position in the direction intersecting the transport path T. In other words, the adjustment unit 54 individually adjusts the supply amount of the process gas G2 per unit time at multiple locations in the supply unit 53 depending on the time it takes for the surface of the rotor 31 to pass through the processing area. The adjustment unit 54 has mass flow controllers (MFCs) 54a provided on each of a pair of paths of the piping 53a. The MFCs 54a are components having a mass flowmeter that measures the flow rate of the fluid and a solenoid valve that controls the flow rate.

As shown in Figures 4, 7 and 9, the antenna 55 is a member that generates inductively coupled plasma for processing the workpiece W passing through the transport path T. The antenna 55 is disposed outside the gas space R and near the window portion 52. When power is applied to the antenna 55, an electric field is generated that is induced in the magnetic field created by the antenna current, and the process gas G2 in the gas space R is turned into plasma. The antenna 55 can change the distribution shape of the generated inductively coupled plasma depending on its shape. In other words, the distribution shape of the inductively coupled plasma can be determined by the shape of the antenna 55. In this embodiment, by giving the antenna 55 the shape shown below, an inductively coupled plasma having a shape approximately similar to the horizontal cross section of the gas space R can be generated.

The antenna 55 has multiple conductors 551a to 551d and a capacitor 552. The multiple conductors 551 are each a strip-shaped conductive member, and are connected to each other via the capacitor 552 to form an electrical path that is rectangular with rounded corners when viewed from the planar direction. The external shape of this antenna 55 is smaller than the size of the opening 51a.

Each capacitor 552 is roughly cylindrical and connected in series between conductors 551a, 551b, 551c, and 551d. If antenna 55 were made of conductors only, the voltage amplitude would be excessive at the end on the power supply side, causing local wear of window 52. Therefore, by dividing the conductor and connecting capacitors 552, small voltage amplitudes are generated at the ends of conductors 551a, 551b, 551c, and 551d, preventing wear of window 52.

However, in the capacitor 552 portion, the continuity of the conductors 551a, 551b, 551c, and 551d is broken, and the plasma density decreases. Therefore, the ends of the conductors 551a, 551b, 551c, and 551d facing the window portion 52 are overlapped in the planar direction to sandwich the capacitor 552 from above and below. More specifically, the connection ends of the conductors 551a, 551b, 551c, and 551d to the capacitor 552 are bent so that the cross section is inverted L-shaped, as shown in FIG. 9. The horizontal surfaces of the ends of the adjacent conductors 551a and 551b are provided with gaps that sandwich the capacitor 552 from above and below. Similarly, the horizontal surfaces of the ends of the conductors 551b and 551c and the horizontal surfaces of the ends of the conductors 551c and 551d are provided with gaps that sandwich the capacitor 552 from above and below.

An RF power supply 55a for applying high frequency power is connected to the antenna 55. A matching box 55b, which is a matching circuit, is connected in series to the output side of the RF power supply 55a. For example, one end of the conductor 551d is connected to the RF power supply 55a. In this example, the conductor 551a is the ground side. A matching box 55b is connected between the RF power supply 55a and one end of the conductor 551d. The matching box 55b stabilizes the plasma discharge by matching the impedance of the input side and the output side.

As shown in Figures 4 to 6, the cooling section 56 is a cylindrical member with rounded rectangular shape and approximately the same external size as the cylindrical body 51, and is provided at a position where its top surface contacts and matches the bottom surface of the cylindrical body 51. Although not shown, a cavity through which cooling water flows is provided inside the cooling section 56. The cavity is connected to a supply port and a drain port connected to a chiller, which is a cooling water circulation device that circulates and supplies cooling water. Cooling water cooled by this chiller is supplied from the supply port, circulates inside the cavity, and is repeatedly discharged from the drain port, thereby cooling the cooling section 56 and suppressing heating of the cylindrical body 51 and the dispersion section 57.

The dispersion section 57 is a cylindrical member with a rounded rectangular shape with approximately the same external dimensions as the cylindrical body 51 and the cooling section 56, and is provided at a position where its top surface is in contact with and coincides with the bottom surface of the cooling section 56, and an opening Ho of the cylindrical section H is provided at its bottom surface. The dispersion section 57 is provided with a dispersion plate 57a. The dispersion plate 57a is spaced from the supply port 512 and is positioned opposite the supply port 512, dispersing the process gas G2 introduced from the supply port 512 and allowing it to flow into the gas space R. The horizontal width of the annular portion of the dispersion section 57 is larger than that of the cylindrical body 51 by the amount that the dispersion plate 57a is provided on the inside.

More specifically, the dispersion plate 57a is raised from the inner edge of the dispersion section 57 around the entire circumference, extending beyond the cooling section 56 to a position close to the bottom surface of the window section 52. As shown in FIG. 5, the flow path of the process gas G2 between the dispersion plate 57a and the supply port 512 is closed on the rotating body 31 side and communicates with the gas space R on the window section 52 side. In other words, between the inner flange 511 and the dispersion plate 57a, an annular gap is formed with the upper part running along the lower surface of the window section 52 and communicating with the gas space R below the window section 52.

The vertical distance between the bottom surface of the dispersion section 57 and the surface of the rotating body 31 is long enough to allow the workpiece W to pass through on the transport path T. In addition, since the dispersion plate 57a enters the gas space R inside the cylindrical body 51, the plasma generation area in the gas space R is the space inside the dispersion plate 57a. The distance between the dispersion plate 57a and the window section 52 is, for example, 1 mm to 5 mm. Setting this distance to 5 mm or less can prevent abnormal discharge from occurring in the gap.

The process gas G2 is introduced into the gas space R from the supply unit 53 via the supply port 512, and a high-frequency voltage is applied to the antenna 55 from the RF power source 55a. Then, an electric field is generated in the gas space R via the window portion 52, and the process gas G2 is turned into plasma. This generates active species such as electrons, ions, and radicals.

[Load lock section]
The load lock unit 60 is a device that, while maintaining the vacuum in the vacuum chamber 21, transports the tray 34 carrying the unprocessed workpieces W from the outside into the vacuum chamber 21 by a transport means (not shown), and transports the tray 34 carrying the processed workpieces W out of the vacuum chamber 21. This load lock unit 60 can have a well-known structure, and therefore a description thereof will be omitted.

[Control device]
The control device 70 is a device that controls each part of the plasma processing apparatus 100. The control device 70 can be configured, for example, by a dedicated electronic circuit or a computer that operates with a predetermined program. In other words, the control contents regarding the control of the introduction and exhaust of the sputtering gas G1 and the process gas G2 into the vacuum chamber 21, the control of the power supply unit 6 and the RF power supply 55a, the control of the rotation of the rotor 31, etc. are programmed. The control device 70 is a device in which the program is executed by a processing device such as a PLC or a CPU, and is capable of handling a wide variety of plasma processing specifications.

Specific items that are controlled are as follows: the rotation speed of the motor 32, the initial exhaust pressure of the plasma processing device 100, the selection of the sputtering source 4, the power applied to the target 41 and the antenna 55, the flow rates, types, introduction times and exhaust times of the sputtering gas G1 and the process gas G2, and the film formation and film processing times.

In particular, in this embodiment, the control device 70 controls the film formation rate by controlling the application of power to the target 41 of the film formation unit 40 and the supply amount of sputtering gas G1 from the gas supply unit 25. The control device 70 also controls the application of power to the antenna 55 and the supply amount of process gas G2 from the supply unit 53 to control the film processing rate.

The configuration of the control device 70 for executing the operations of each unit as described above will be described with reference to the virtual functional block diagram of FIG. 10. That is, the control device 70 has a mechanism control unit 71, a power supply control unit 72, a gas control unit 73, a memory unit 74, a setting unit 75, and an input/output control unit 76.

The mechanism control unit 71 is a processing unit that controls the drive sources, solenoid valves, switches, power supplies, etc. of the exhaust unit 23, gas supply unit 25, supply unit 53, adjustment unit 54, motor 32, load lock unit 60, etc. The power supply control unit 72 is a processing unit that controls the power supply unit 6 and RF power supply 55a. For example, the power supply control unit 72 individually controls the power applied to the targets 41A, 41B, and 41C. If it is desired to make the film formation rate uniform over the entire workpiece W, the power is increased successively, such as target 41A < target 41B < target 41C, taking into consideration the speed difference between the inner circumference side and the outer circumference side. In other words, the power may be determined in proportion to the speed of the inner circumference side and the outer circumference side. However, the proportional control is only one example, and the power may be increased as the speed increases, so that the processing rate is set to be uniform. In addition, the power applied to the target 41 may be increased in areas where the film thickness of the film formed on the workpiece W is desired to be thick, and the power applied to the target 41 may be decreased in areas where the film thickness is desired to be thin.

The gas control unit 73 is a processing unit that controls the amount of process gas G2 introduced by the adjustment unit 54. For example, the supply amount per unit time of the process gas G2 from each supply port 512 is individually controlled. If it is desired to make the film processing rate uniform over the entire work W, the supply amount from each supply port 512 is increased sequentially from the inner side to the outer side, taking into account the speed difference between the inner side and the outer side. Specifically, the supply amount is set as supply port 512A < supply port 512B < supply port 512C < supply port 512D, supply port 512a < supply port 512b < supply port 512c < supply port 512d. In other words, the supply amount may be determined in proportion to the speed of the inner side and the outer side. In addition, the supply amount of the process gas G2 supplied from each supply port 512 is adjusted according to the film thickness to be formed on the work W. In other words, for the portion where the film thickness is to be made thicker, the supply amount of the process gas G2 is increased so that the amount of film processing increases. Then, in the area where the film thickness is to be thinned, the supply amount of process gas G2 is reduced so that the amount of film processing is reduced. Also, for example, in the case of film processing for a film formed so that the film thickness increases toward the inner circumference, the supply amount of process gas G2 can be set to be greater toward the inner circumference. This, combined with the relationship with the speed described above, may result in a uniform supply amount from each supply port 512. In other words, the adjustment unit 54 may adjust the supply amount of process gas G2 supplied from each supply port 512 according to the film thickness formed on the workpiece W and the time it takes for the rotating body 31 to pass through the processing area. The gas control unit 73 also controls the introduction amount of sputtering gas G1.

The memory unit 74 is a component that stores information necessary for control in this embodiment. Information stored in the memory unit 74 includes the exhaust volume of the exhaust unit 23, the power applied to each target 41, the supply amount of sputtering gas G1, the power applied to the antenna 55, and the supply amount of process gas G2 for each supply port 512. The setting unit 75 is a processing unit that sets information input from the outside in the memory unit 74. The power applied to the antenna 55 is determined, for example, by the desired film thickness to be formed during one rotation of the rotor 31 and the rotation speed (rpm) of the rotor 31.

Furthermore, the power applied to the targets 41A, 41B, and 41C may be linked to the amount of process gas G2 supplied from the supply ports 512A-D and 512a-d. In other words, when the rotation speed (rpm) of the rotor 31 is constant and the power applied to the targets 41A, 41B, and 41C is set by the setting unit, the supply amount from each supply port 512A-D and 512a-d may be set in proportion to this. Also, when the rotation speed (rpm) of the rotor 31 is constant and the supply amount from each supply port 512A-D and 512a-d is set by the setting unit, the power applied to each target 41A, 41B, and 41C may be set in proportion to this.

Such settings can be made, for example, as follows. First, the relationship between the film thickness and the corresponding applied power or supply amount of process gas G2, and the relationship between the applied power and the corresponding supply amount of process gas G2 are obtained in advance, for example, through experiments. Then, at least one of these is tabulated and stored in the memory unit 74. Then, the setting unit 75 refers to the table and determines the applied power or supply amount according to the input film thickness, applied power, or supply amount.

The input/output control unit 76 is an interface that controls the conversion of signals between each part to be controlled and the input/output. In addition, an input device 77 and an output device 78 are connected to the control device 70. The input device 77 is an input means such as a switch, touch panel, keyboard, or mouse that allows the operator to operate the plasma processing device 100 via the control device 70. For example, the selection of the film forming unit 40 and film processing unit 50 to be used, the desired film thickness, the applied power to each target 41A-41C, the supply amount of process gas G2 from each supply port 512A-D, 512a-d, etc. can be input by the input means.

The output device 78 is an output means such as a display, lamp, meter, etc. that makes information for checking the status of the device visible to the operator. For example, the output device 78 can display an input screen for information from the input device 77. In this case, the targets 41A, 41B, 41C and each of the supply ports 512A-D, 512a-d may be displayed in schematic diagrams so that the positions of each can be selected and numerical values can be input. Furthermore, the targets 41A, 41B, 41C and each of the supply ports 512A-D, 512a-d may be displayed in schematic diagrams so that the values set for each can be displayed numerically.

[Action]
The operation of the present embodiment as described above will be described below with reference to Figures 1 to 10. Although not shown, the tray 34 carrying the workpiece W is loaded, transported, and unloaded into the plasma processing apparatus 100 by a transport means such as a conveyor or a robot arm.

The multiple trays 34 are sequentially loaded into the vacuum vessel 20 by the transport means of the load lock unit 60. The rotating body 31 sequentially moves the empty holding units 33 to the loading location from the load lock unit 60. The holding units 33 individually hold each of the trays 34 loaded by the transport means. In this way, as shown in Figures 2 and 3, all of the trays 34 carrying the workpieces W to be film-formed are placed on the rotating body 31.

The process of forming a film on the workpiece W introduced into the plasma processing apparatus 100 as described above is performed as follows. The following operation is an example of performing film formation and film processing by operating one of the film formation units 40 and the film processing unit 50, such as only the film formation unit 40A and only the film processing unit 50A. However, multiple sets of film formation units 40 and film processing units 50 may be operated to increase the processing rate. Another example of film formation and film processing by the film formation unit 40 and the film processing unit 50 is the process of forming a silicon oxynitride film. The silicon oxynitride film is formed by repeating the process of penetrating oxygen ions and nitrogen ions each time silicon is attached to the workpiece W at the atomic level while circulating and transporting the workpiece W.

First, the vacuum chamber 21 is constantly evacuated and depressurized by the exhaust section 23. Then, when the vacuum chamber 21 reaches a predetermined pressure, the rotating body 31 rotates as shown in Figures 2 and 3. As a result, the workpiece W held by the holding section 33 moves along the transport path T and passes under the film forming sections 40A, 40B, 40C and the film processing sections 50A, 50B. When the rotating body 31 reaches a predetermined rotation speed, the gas supply section 25 of the film forming section 40 then supplies sputtering gas G1 to the periphery of the target 41. At this time, the supply section 53 of the film processing section 50 also supplies process gas G2 to the gas space R.

In the film-forming section 40, the power supply unit 6 applies power to each of the targets 41A, 41B, and 41C. This converts the sputtering gas G1 into plasma. In the sputtering source 4, active species such as ions generated by the plasma collide with the target 41 and scatter particles of the film-forming material. As a result, particles of the film-forming material are deposited on the surface of the workpiece W as it passes through the film-forming section 40, producing a film. In this example, a layer of silicon is formed.

The power applied by the power supply unit 6 to each target 41A, 41B, 41C is set in the memory unit 74 so that it increases from the inner circumference to the outer circumference of the rotating body 31. The power supply control unit 72 outputs instructions to control the power applied by the power supply unit 6 to each target 41 according to the power set in the memory unit 74. Due to this control, the amount of film formed per unit time by sputtering increases from the inner circumference to the outer circumference, but the passing speed of the rotating body 31 increases from the inner circumference to the outer circumference. As a result, the film thickness of the entire workpiece W is uniform.

The workpiece W is not heated even if it passes through a film-forming unit 40 or a film-processing unit 50 that is not in operation, because no film is formed or processed. In this non-heated area, the workpiece W releases heat. An example of a film-forming unit 40 that is not in operation is film-forming positions M4 and M5. An example of a film-processing unit 50 that is not in operation is film processing position M3.

Meanwhile, the workpiece W on which the film has been formed passes through a position facing the opening Ho of the tube portion H in the processing unit 5. In the processing unit 5, as shown in FIG. 8, oxygen and nitrogen as the process gas G2 are supplied from the supply portion 53 through the supply port 512 into the gas space R, and a high-frequency voltage is applied from the RF power source 55a to the antenna 55. The application of the high-frequency voltage creates an electric field in the gas space R through the window portion 52, generating plasma. Oxygen ions and nitrogen ions generated by the generated plasma collide with the surface of the workpiece W on which the film has been formed, and penetrate the film material.

The flow rate per unit time of the process gas G2 introduced from the supply port 512 is set in the memory unit 74 so that it is smaller toward the inner circumference side of the rotating body 31 and is larger toward the outer circumference side. The gas control unit 73 outputs an instruction so that the adjustment unit 54 controls the flow rate of the process gas G2 flowing through each pipe 53a according to the flow rate set in the memory unit 74. Therefore, the amount of active species such as ions per unit volume generated in the gas space R is greater on the outer circumference side than on the inner circumference side. Therefore, the film processing amount, which is influenced by the amount of active species, increases from the inner circumference side to the outer circumference side. However, the processing area to be processed by the film is a rounded rectangular shape similar to the opening 51a of the cylindrical body 51. Therefore, the width of the processing area, that is, the width in the rotation direction, is the same in the radial direction. In other words, the processing area has a constant width in the radial direction. On the other hand, the workpiece W passes through the processing area faster from the inner circumference side to the outer circumference side. Therefore, the time it takes for the workpiece W to pass through the processing area becomes shorter as it moves from the inner circumference side to the outer circumference side. By increasing the supply of process gas G2 toward the outer periphery, the film processing amount increases toward the outer periphery, which compensates for the short passing time through the processing area. As a result, the overall film processing amount of the workpiece W becomes uniform.

In addition, when performing film processing using two or more kinds of process gases G2, such as oxynitridation, it is necessary to completely turn the film formed in the film forming unit 40 into a compound film while the rotor rotates once, and at the same time, to make the composition of the film uniform over the entire film forming surface. This embodiment is suitable for the plasma processing apparatus 100 that performs film processing using two or more kinds of process gases G2. For example, suppose that a film with a ratio of x and y of silicon oxynitride (SiO _x N _y ) of 1:1 is desired. Then, it is necessary to control both the amount of active species that sufficiently turns the formed film into a compound film and the ratio of oxygen and nitrogen contained in the active species. In this embodiment, the supply points of the process gas G2 are multiple, and the supply amount of the process gas G2 at each supply point can be adjusted for each type of process gas G2, so that both the amount and the ratio are easy to control.

As shown in FIG. 5, the process gas G2 supplied from the supply port 512 spreads horizontally along the vertical surface of the dispersion plate 57a by colliding with the dispersion plate 57a, and flows into the gas space R from the upper edge of the dispersion plate 57a. In this way, the process gas G2 is dispersed, so that the flow rate of the process gas G2 near the supply port 512 does not increase extremely. In other words, the distribution of the gas flow rate from the inner circumference side to the outer circumference side is prevented from being locally high, and increases at a gradient that is close to linear. This prevents the film processing rate from increasing or decreasing partially, causing variations in processing.

During the above-described process of forming the film, the rotating body 31 continues to rotate and circulates and transports the tray 34 carrying the workpiece W. In this manner, the compound film is formed by circulating the workpiece W and repeating the film formation and film processing. In this embodiment, a silicon oxynitride film is formed on the surface of the workpiece W as the compound film.

After a predetermined processing time has elapsed during which the silicon oxynitride film has reached the desired thickness, the film forming unit 40 and the film processing unit 50 are stopped. In other words, the application of power to the target 41 by the power supply unit 6, the supply of the process gas G2 from the supply port 512, the application of voltage by the RF power supply 55a, etc. are stopped.

After the film formation process is completed in this manner, the trays 34 carrying the workpieces W are sequentially positioned in the load lock section 60 by the rotation of the rotating body 31, and are transported to the outside by the transport means.

[Film formation test results]
The results of a film formation test of an example corresponding to this embodiment and a comparative example will be described with reference to the graph in Fig. 11. Examples 1 to 3 are test results in which the flow rates per unit time of oxygen and nitrogen from the multiple supply ports 512 were increased stepwise from the inner circumference side to the outer circumference side. Examples 1 and 3 are examples in which the dispersion plate 57a was used, and Example 2 is an example in which gas was directly supplied from the supply port 512 to the gas space without using the dispersion plate 57a.

However, in Examples 2 and 3, the flow rate of the process gas G2 at the outermost supply ports 512D and 512d outside the film formation region F is not maximized, but is set to be less than that of the supply ports 512B, C, 512b, and c. In other words, the flow rates are set so that supply port 512A < supply port 512D < supply port 512B < supply port 512C, and supply port 512a < supply port 512d < supply port 512b < supply port 512c.

Since the workpiece W does not pass through a position outside the film formation area F, there is no need to supply the process gas G2. However, as shown in FIG. 7, when the cylindrical body 51 is formed outside the film formation area F with a margin, if the process gas G2 is not supplied at all to the outside of the film formation area F, the process gas G2 will diffuse outside the film formation area F near the inner end or the outer end of the film formation area F. As a result, the processing rate will decrease near the inner end or the outer end of the film formation area F. For this reason, it is advisable to supply the process gas G2 to the outside of the film formation area F as a backup. The amount of process gas G2 at this time is sufficient to compensate for the decrease due to diffusion, so it is sufficient that the amount is sufficient to prevent diffusion in relation to the size of the area that is the margin described above. However, there are cases where it is necessary to supply a larger amount than the supply ports 512C and 512c. In this way, the supply ports 512A, 512a, 512D, and 512d located outside the film formation region F may be excluded from the adjustment of the process gas G2 by the adjustment unit 54 according to the passage time.

In the comparative example, the process gas G2 is supplied from one location. The other conditions are common to Examples 1 to 3 and the comparative example. For example, the voltage applied to the target 41 was controlled so that the film formed on the workpiece W by the film forming unit 40 had a uniform thickness.

In the graph of Figure 11, the horizontal axis is the radial distance [mm] from the center of rotation of the rotor 31 to the outer periphery, and the vertical axis is the refractive index Nf of the deposited film. Since the refractive index of the film changes depending on the degree of film treatment, the degree of film treatment can be determined by measuring the refractive index. As is clear from this graph, the comparative example had a large variation in refractive index between the inner and outer periphery sides, at ±4.17%, while Example 1 had a variation of ±1.21%, and Example 2 had a variation of ±1.40%. Example 3 had the smallest variation at ±1.00%.

These test results show that by adjusting the flow rate of the process gas G2 from each supply port 512, it is possible to suppress the variation in film processing from the inner circumference side to the outer circumference side. It is also found that by providing the dispersion plate 57a, it is possible to make the degree of film processing more uniform overall.

Furthermore, the supply ports 512D, 512d outside the film formation region F are less involved in the film processing, and it is not necessary to maximize the flow rate of the process gas G2, but it can be seen that supplying even a small amount of process gas G2 can make the degree of film processing more uniform. This is also thought to be the same for the supply ports 512A, 512a on the inner circumference side. In other words, by providing the supply port 512 outside the film formation region F, it is possible to obtain effects such as making the degree of film processing uniform.

[Action and Effect]
(1) This embodiment includes a vacuum vessel 20 capable of creating a vacuum inside, a transport unit 30 provided within the vacuum vessel 20 and having a rotor 31 which rotates with a workpiece W mounted thereon, and which circulates and transports the workpiece W along a circumferential transport path T by rotating the rotor 31, a cylindrical portion H having an opening Ho at one end extending in a direction toward the transport path T inside the vacuum vessel 20, a window portion 52 provided in the cylindrical portion H and separating a gas space R into which a process gas G2 is introduced between the inside of the cylindrical portion H and the rotor 31 and the outside of the gas space R, a supply unit 53 which supplies the process gas G2 to the gas space R, and an antenna 55 which is provided outside the gas space R and located near the window portion 52 and which, when power is applied, generates inductively coupled plasma in the process gas G2 in the gas space R for plasma processing the workpiece W passing through the transport path T. The supply unit 53 supplies process gas G2 from multiple locations where the surface of the rotating body 31 passes through a processing area where plasma processing is performed at different times, and has an adjustment unit 54 that individually adjusts the supply amount of process gas G2 per unit time at the multiple locations of the supply unit 53 according to the time it takes to pass through the processing area.

Therefore, the degree of plasma treatment on the workpiece W circulated and transported by the rotor 31 can be adjusted according to the position where the passing speed on the surface of the rotor 31 is different. Therefore, the desired plasma treatment can be performed, such as making the degree of treatment on the workpiece W uniform or changing the degree of treatment at a desired position. This is more effective the larger the diameter of the rotor 31 and the wider the film formation area F, that is, the greater the difference in circumferential speed between the inner and outer sides of the film formation area F. In this embodiment, the shape of the opening 51a of the cylindrical body 51 through which the process gas G2 is introduced is a rounded rectangular shape similar to the antenna 55, so that the process gas G2 can be more accurately supplied to the gas space R near the antenna 55, and highly efficient plasma can be obtained.

(2) In addition, in this embodiment, the supply unit 53 has a plurality of supply ports 512 that are provided corresponding to a plurality of locations to which the process gas G2 is supplied, and that supply the process gas G2 to the gas space R, and a dispersion plate 57a that is spaced apart from the supply ports 512 and positioned opposite the supply ports 512, and that disperses the process gas G2 supplied from the supply ports 512 and causes it to flow into the gas space R.

Therefore, the process gas G2 is dispersed by the dispersion plate 57a, and the gas flow does not concentrate locally, preventing the occurrence of processing variations. In addition, the dispersion plate 57a can prevent hollow cathode discharge from occurring at the supply port 512. For example, in a state where the dispersion plate 57a is not present and the supply port 512 is exposed to the gas space R, there is a risk of hollow cathode discharge occurring at the supply port 512. If hollow cathode discharge occurs, it will interfere with the plasma due to inductive coupling and will not be able to form a uniform plasma. In this embodiment, the dispersion plate 57a is spaced apart from the supply port 512 and is positioned opposite the supply port 512, thereby preventing hollow cathode discharge from occurring between the dispersion plate 57a and the supply port 512. Furthermore, the process gas G2 is introduced from the supply port 512 through the dispersion plate 57a into the gas space R near the window portion 52. This allows the process gas G2 to be more accurately supplied to the gas space R near the antenna 55, resulting in a highly efficient plasma.

(3) The flow path of the process gas G2 between the dispersion plate 57a and the supply port 512 is closed on the rotating body 31 side and communicates with the gas space R on the window portion 52 side.

As a result, the process gas G2 is supplied along the bottom surface of the window portion 52 near the window portion 52 where the electric field is generated, forming a dense plasma and improving processing efficiency. Furthermore, since the flow path of the process gas G2 between the dispersion plate 57a and the supply port 512 is blocked on the side of the rotor 31, the process gas G2 accumulates on the bottom side of the flow path. The dispersion plate 57a is cooled by the cooling section 56 via the accumulated process gas G2. When the dispersion plate 57a is cooled in this manner, the deactivation of the plasma is suppressed, and the plasma can be generated with high efficiency. This effect is further enhanced by cooling the upper surface of the dispersion section 57 in contact with the bottom surface of the cooling section 56.

(4) The adjustment unit 54 adjusts the amount of process gas G2 supplied from each supply port 512 depending on the position of the rotating body 31 in the direction intersecting the transport path T.

As a result, the supply amount of process gas G2 from the multiple supply ports 512 can be individually adjusted according to the positions on the surface of the rotating body 31 where the passing speed differs.

(5) A film forming unit 40 is provided at a position facing the workpiece W circulated along the transport path T, and forms a film by depositing a film-forming material on the workpiece W by sputtering. The film of the film-forming material deposited on the workpiece W by the film forming unit 40 is subjected to film processing using inductively coupled plasma.

Therefore, the degree of film processing for the formed film can be adjusted according to the position where the passing speed on the surface of the rotating body 31 is different.

(6) The supply ports 512 correspond to the area where the film forming unit 40 forms a film, and are provided within the film forming area F, which is a circular area along the transport path T, and are also provided outside the film forming area F. The supply ports 512 provided outside the film forming area F are not subject to adjustment of the supply amount of the process gas G2 by the adjustment unit 54.

In this way, by supplying process gas G2 even outside the film formation region F, it is possible to prevent a shortage of the flow rate of process gas G2 at the end of the film formation region F. For example, even if the outermost supply port 512 or the innermost supply port 512 is outside the film formation region F, it is possible to uniformize the film processing by supplying process gas G2. However, outside the outermost film formation region F, the flow rate is not insufficient in the film formation region F even if the flow rate is not set to the maximum, so the flow rate can be saved. In other words, the supply points of process gas G2 outside the film formation region F function as auxiliary supply points or auxiliary supply ports that supplement the flow rate of process gas G2 in the film formation region F.

(7) The supply ports 512 are positioned opposite each other across the gas space R and are arranged in a direction along the transport path T. This allows the process gas G2 to be distributed throughout the gas space R in a short period of time.

(8) The adjustment unit 54 adjusts the supply amount of the process gas G2 introduced from each supply port 512 according to the film thickness to be formed on the workpiece W and the time for the rotating body 31 to pass through the processing area. This allows film processing appropriate for the film thickness.

(9) The pipes 53b and 53c are connected to the cylindrical body 51 to discharge the process gas G2 from the cylindrical body 51, so that the cylindrical part H can be easily removed from the plasma processing apparatus 100. In other words, the cylindrical part H can be removed while the pipes 53b and 53c are connected to the cylindrical body 51. For example, if the pipes 53b and 53c are introduced into the vacuum chamber 21 from the side of the vacuum container 20 and connected to the cylindrical body 51, when removing the cylindrical part H from the plasma processing apparatus 100, it is necessary to perform an operation to disconnect the pipes 53b and 53c from the cylindrical body 51. In addition, when attaching the cylindrical part H to the plasma processing apparatus 100, the pipes 53b and 53c must be reconnected to the cylindrical body 51, which makes the operation complicated. Alternatively, when the pipes 53b and 53c are introduced into the vacuum chamber 21 from the side of the vacuum container 20, it is also possible to provide a notch in the cylindrical part H to avoid the pipes 53b and 53c. In this case, the cylindrical portion H can be easily removed from the plasma processing apparatus 100, but most of the process gas G2 dispersed by the dispersion plate 57a leaks from the notch. Therefore, the process gas G2 cannot be introduced into the gas space R near the antenna 55, so high-efficiency plasma cannot be obtained. In addition, the leaked process gas G2 may flow to the film forming section 40 and mix with the sputtering gas G1. If the process gas G2 and the sputtering gas G1 mix, the film forming rate of the film forming section 40 may decrease. If the film forming rate of the film forming section 40 decreases, not only will the productivity decrease, but the optimal supply amount obtained in advance will no longer be optimal, so the uniformity of the film quality may deteriorate. In contrast, in the cylindrical portion H of this embodiment, the vertical distance between the bottom surface of the dispersion section 57 and the surface of the rotating body 31 is narrowed to a length that allows the workpiece W to pass through. Therefore, the process gas G2 is prevented from leaking from the gas space R. Even if there is a very small amount of leakage, the partition 44 prevents it from flowing into the film forming section 40.

(10) The supply amount of process gas G2 from multiple locations can be calculated based on specific conditions. For this reason, the control device 70 may have a supply amount calculation unit that calculates the supply amount of process gas G2. The supply amount calculation unit calculates the supply amount of process gas G2 based on, for example, conditions input from the input device 77 or conditions stored in the memory unit 74. The calculated supply amount is set in the memory unit 74. Based on the set supply amount, the adjustment unit 54 adjusts the supply amount of process gas G2 supplied from each supply port 512. A more specific example is described below.

(composition)
The basic configuration of the plasma processing apparatus 100 is similar to that of the above embodiment. The control device 70 has a supply amount calculation unit, and the memory unit 74 stores the film thickness at the innermost or outermost circumference, the optimal supply amount for that film thickness, and the distance of each supply port 512 from the center of rotation of the rotor 31 (the radius of a circle passing through the center of each supply port 512).

(Calculation processing)
When it is desired to form a film having a uniform thickness and quality over a large area, the following four conditions must be taken into consideration when adjusting the supply amount of the process gas G2.
[1] The thickness of the film formed in the film forming section during one rotation of the rotor
[2] Thickness distribution of the film formed in the radial direction of the rotating body
[3] Speed difference between the inner and outer circumferences of a rotating body
[4] Width of plasma generation area (width of processing area)

Here, condition [2] can be removed from the conditions if power is applied individually to each target 41A, 41B, 41C of the film-forming section 40 to achieve a uniform film thickness. Also, as in the above embodiment, by giving the antenna 55 and gas space R a rounded rectangular shape when viewed from the planar direction, the width of the processing area becomes the same from the innermost circumference to the outermost circumference of the film-forming area F. Therefore, the same plasma density can be achieved within that width range, and condition [4] can also be removed from the conditions.

Therefore, the supply amount of each supply port 512 can be determined from the conditions [1] and [3]. That is, as the condition [1], either one of the film thicknesses at the innermost circumference or the outermost circumference of the film formation area F and the optimal supply amount suitable for that film thickness are obtained by a prior experiment or the like. Then, since the speed difference between the inner circumference and the outer circumference in [3] is related (proportional) to the radius of the inner circumference and the outer circumference, the supply amount of each of the multiple supply ports 512 can be determined from the radial position (distance from the center of rotation) of the multiple supply ports 512, the above film thickness, and the optimal supply amount. Note that the film thickness of the film formed during one rotation of the rotor 31 at the innermost circumference of the film formation area F, the film thickness of the film formed during one rotation of the rotor 31 at the outermost circumference of the film formation area F, the optimal supply amount suitable for the above film thickness, and the radial position of each supply port 512 are included in the information stored in the memory unit 74.

For example, the optimum supply amount of the innermost supply port 512 for a predetermined thickness of a film formed in the film forming unit 40 is a, the radius of the innermost circumference is Lin, the radius of the outermost circumference is Lou, and the optimum supply amount of the outermost supply port 512 is A. First, a case will be described in which the optimum supply amount a of the innermost supply port 512 is known. The supply amount calculation unit acquires the innermost optimum supply amount a, the radius Lin of the circle passing through the innermost supply port 512, and the radius Lou of the circle passing through the outermost supply port 512 from the storage unit 74, and calculates the optimum supply amount A of the outermost circumference based on the following formula.
A=a×Lou/Lin
Similarly, the optimal supply amounts of the other supply ports 512 can be obtained according to the ratio of the radii. In other words, if the optimal supply amount of the supply port 512 is Ax and the radius of the circle that passes through the supply port 512 is Px, the optimal supply amount Ax can be obtained based on the following formula.
Ax=a×Px/Lin
Conversely, when the optimal supply amount A of the outermost supply port 512 is known, the optimal supply amount ax of each supply port 512 can be calculated from the radius px of the circle passing through that supply port 512 based on the following formula.
ax=A×px/Lou

(effect)
As described above, [1] if the thickness of the film formed by the film forming unit 40 during one rotation of the rotor is known, the supply amount from the multiple supply ports 512 is automatically determined. Therefore, the amount of data stored in the memory unit 74 can be reduced compared to the case where a large amount of data is stored as an expected pattern of the supply amount from each supply port 512. For example, in the case of a film whose refractive index changes depending on the composition, such as SiON, the supply amount from each supply port 512 is automatically determined from the film thickness at the innermost or outermost circumference of the film forming region F, so that a film with a desired refractive index can be obtained by adjusting the mixture ratio of _N2 and _O2 .

[Other embodiments]
The present invention is not limited to the above-described embodiment, and also includes the following aspects.
(1) Regarding the film-forming material, various materials that can be formed into a film by sputtering can be used. For example, tantalum, titanium, aluminum, etc. can be used. Regarding the material for forming the compound, various materials can be used.

(2) The number of targets in the film formation section is not limited to three. There may be one, two, four or more targets. By increasing the number of targets and adjusting the applied power, more precise control of film thickness is possible. Also, there may be one, two, four or more film formation sections. By increasing the number of film formation sections, the film formation rate can be improved. Correspondingly, the number of film processing sections can be increased to improve the film processing rate.

(3) Film formation by a film formation unit is not necessarily required, and the film formation unit need not be provided. In other words, the present invention is not limited to plasma processing apparatuses that perform film processing, but can be applied to plasma processing apparatuses that use activated species generated by plasma to perform processing on a processing object. For example, the processing unit may be configured as a plasma processing apparatus that generates plasma in a gas space to perform surface modification such as etching and ashing, cleaning, etc. In this case, for example, an inert gas such as argon may be used as the process gas.

(4) The process gas supply port does not have to be provided in the cylindrical body. For example, each pipe in the supply section may be extended into the cylindrical body, and the tip of each pipe may serve as a supply port. The tip of the pipe may be made nozzle-shaped by reducing the diameter. In this case, too, pipes may be provided not only in the film formation region, but also outside the film formation region, and function as auxiliary supply ports or auxiliary nozzles that supplement the flow rate of the process gas in the film formation region.

(5) The number of locations and supply ports to which the supply unit supplies process gas may be any number as long as the locations have different passing speeds on the surface of the rotating body, and are not limited to the numbers exemplified in the above embodiment. By providing three or more in a row within the film formation region, more precise flow rate control according to the processing position can be performed. Furthermore, the more the number of supply locations and supply ports is increased, the more the gas flow rate distribution can be made closer to linear, preventing local processing variations. The supply ports may be provided in one row rather than in two opposing rows on the cylindrical body. Furthermore, the supply ports do not have to be arranged in a straight line, but may be arranged at positions offset in the vertical direction.

(6) The configuration of the adjustment unit is not limited to the above example. It may be possible to provide manual valves in each pipe and adjust manually. Since it is sufficient to adjust the amount of gas supplied, the pressure may be kept constant and adjustment may be performed by opening and closing a valve, or the pressure may be increased or decreased. The adjustment unit may be realized by a supply port. For example, supply ports of different diameters may be provided according to positions where the passing speed on the surface of the rotating body differs, and the supply amount of process gas may be adjusted. The supply port may be replaceable with a nozzle of a different diameter. Also, the diameter of the supply port may be changeable by a shutter or the like.

(7) Since the speed is the distance traveled per unit time, the amount of process gas supplied from each supply port may be set in relation to the time required to pass through the processing area in the radial direction.

(8) The shapes of the cylindrical body, window, and antenna are not limited to those exemplified in the above embodiment. The horizontal cross section may be square, circular, or elliptical. However, a shape with equal spacing between the inner and outer circumferences makes it easier to adjust the supply amount of process gas according to the difference in processing time, since the passing time of the workpiece W on the inner and outer circumferences is different. In addition, if the spacing between the inner and outer circumferences is equal, a space can be created between the partition 44 that separates the film forming section 40 and the film processing section 50. This increases the effect of preventing the flow of process gas G2, such as oxygen or nitrogen, into the film forming section 40. Furthermore, for example, the antenna may be formed into a fan shape, so that the processing area is fan-shaped. In this case, even if the speed becomes faster toward the outer circumference, the time required to pass through the processing area is the same or almost the same, so the supply amount of process gas may be the same.

(9) The number of trays and workpieces simultaneously transported by the transport unit, and the number of holding units that hold them, need only be at least one, and are not limited to the numbers exemplified in the above embodiment. In other words, it may be a configuration in which one workpiece is circulated and transported, or a configuration in which two or more workpieces are circulated and transported. It may also be a configuration in which the works are arranged in two or more rows in the radial direction and circulated and transported.

(10) In the above embodiment, the rotating body is a rotating table, but the rotating body is not limited to a table shape. It may be a rotating body that rotates while holding a tray or workpiece on an arm extending radially from the center of rotation. The film-forming unit and film-processing unit may be located on the bottom side of the vacuum vessel, and the top-bottom relationship between the film-forming unit and film-processing unit and the rotating body may be reversed. In this case, the surface of the rotating body on which the holding unit is arranged is the surface that faces downward when the rotating body is horizontal, i.e., the bottom surface.

(11) Although the above describes the embodiments of the present invention and the modified examples of each part, these embodiments and the modified examples of each part are presented as examples and are not intended to limit the scope of the invention. These novel embodiments described above can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims.

100 Plasma processing device
20 Vacuum vessel
20a Ceiling
20b Inner bottom surface
20c Inner circumferential surface
21 Vacuum chamber
21a Opening
21b O-ring
22 Exhaust port
23 Exhaust section
24 Introduction
25 Gas supply unit
30 Conveying section
31 Rotating body
32 Motor
33 Holding part
34 Tray
40, 40A, 40B, 40C Film forming part
4. Sputtering source
41, 41A, 41B, 41C Target
42 Backing plate
43 Electrode
44 Partition
5 Processing unit
50, 50A, 50B Membrane processing section
51 Cylindrical body
51a Opening
51b Outer flange
511 Inner flange
511a, 511b, 511c shelf surface
512, 512A-D, 512a-d supply port
52 Window section
53 Supply Section
53a, 53b, 53c Pipes
54 Adjustment section
54a MFC
55 Antenna
55a RF power supply
55b Matching box
551, 551a-d Conductor
552 Capacitor
56 Cooling section
57 Dispersion section
57a Dispersion plate
6 Power supply unit
60 Load lock section
70 Control device
71 Mechanism control unit
72 Power supply control unit
73 Gas control section
74 Memory section
75 Setting section
76 Input/Output Control Unit
77 Input device
78 Output device
E Exhaust
T Transport route
M1, M3 Membrane processing positions
M2, M4, M5 deposition positions
G Reactive gas
G1 Sputtering gas
G2 Process gas
H Cylinder
H Opening
F Film formation area
R Gas space

Claims (6)

a vacuum vessel capable of creating a vacuum inside;
a conveying section that is provided in the vacuum vessel, has a rotating body that rotates with a workpiece mounted thereon, and conveys the workpiece in a circumferential conveying path by rotating the rotating body;
a cylindrical portion having an opening at one end extending in a direction toward the transfer path inside the vacuum container;
a window portion provided in the cylindrical portion and separating a gas space between the inside of the cylindrical portion and the rotor into which a process gas is introduced and an outside of the gas space;
a supply unit that supplies the process gas to the gas space from supply ports provided at a plurality of locations along an inner wall of the cylindrical portion;
an antenna that is disposed outside the gas space and in the vicinity of the window portion, and that generates an inductively coupled plasma in the process gas in the gas space by applying power thereto, for plasma processing the workpiece passing through the transport path;
having
the supply unit supplies two types of the process gas from the supply ports at positions where the surface of the rotating body passes through a processing region where the plasma processing is performed at different times;
13. A plasma processing apparatus comprising: an adjusting unit that adjusts the supply amount per unit time of each type of process gas supplied to each of said supply ports individually in accordance with said passage time. The process gas supplied from the supply unit is nitrogen and oxygen;
2. The plasma processing apparatus according to claim 1, wherein the adjustment unit adjusts the supply amounts of the nitrogen and the oxygen supplied from the supply port individually in accordance with the passing time. a film forming unit that is provided at a position facing the workpiece that is circulated along the transport path and that deposits a film forming material on the workpiece by sputtering to form a film;
2. The plasma processing apparatus according to claim 1, wherein the plasma processing is performed by using the inductively coupled plasma to a film of a film-forming material deposited on the workpiece by the film-forming unit. the supply port corresponds to a region where the film forming unit forms a film, and is provided in an annular film forming region along the transport path, and is also provided outside the film forming region;
4. The plasma processing apparatus according to claim 3, wherein the supply port provided outside the film formation region is not included in the target of the adjustment of the supply amount of the process gas by the adjustment unit. The plasma processing apparatus according to any one of claims 1 to 3, characterized in that the supply ports are arranged at positions facing each other across the gas space and in a direction along the transport path. The plasma processing apparatus according to any one of claims 1 to 3, characterized in that the adjustment unit adjusts the amount of process gas supplied from each supply port according to the film thickness to be formed on the workpiece and the passing time.

Images