CN112226734A

CN112226734A - Negative ion generating device

Info

Publication number: CN112226734A
Application number: CN201910634859.0A
Authority: CN
Inventors: 北见尚久
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2019-07-15
Filing date: 2019-07-15
Publication date: 2021-01-15

Abstract

The invention provides an anion generating device, which can irradiate anions to an object at a proper time. The control unit (50) controls the application of voltage by the voltage application unit (90) according to the measurement result of the potential measurement unit (110) after the generation of plasma (P) by the plasma gun (7) is stopped. Thus, the control unit (50) can irradiate the object (11) to be film-formed with negative ions at a timing that can avoid a large amount of electrons from being irradiated to the object.

Description

Negative ion generating device

Technical Field

The present invention relates to an anion generating apparatus.

Background

As an anion generator for generating anions using plasma, an anion generator described in patent document 1 is known. The negative ion generator generates plasma in the chamber and supplies a raw material of negative ions into the chamber, thereby generating negative ions in the chamber.

Patent document 1: japanese patent laid-open publication No. 2017-025407

Here, when plasma is generated in the chamber, not only negative ions but also electrons are generated in the chamber. For example, when negative ions are not generated in the chamber and a large amount of electrons are present, when negative ions are irradiated to the object, electrons are also irradiated to the object. When a large amount of electrons are irradiated to the object, the object may have a high temperature. Therefore, when negative ions are irradiated to the object, it is required to irradiate the negative ions at an appropriate timing that can avoid irradiation of a large amount of electrons to the object.

Disclosure of Invention

Accordingly, an object of the present invention is to provide an anion generator capable of irradiating negative ions to an object at an appropriate timing.

In order to solve the above problem, an anion generating apparatus according to the present invention generates anions using plasma and irradiates the anions to an object, the anion generating apparatus including: a chamber for accommodating an object and generating negative ions therein; a plasma gun generating a plasma within the chamber; a potential measuring unit for measuring a potential in the chamber; a voltage applying unit capable of applying a positive voltage to an object; and a control unit for controlling the negative ion generator, wherein the control unit controls the voltage application unit to apply the voltage according to the measurement result of the potential measuring unit after stopping the generation of the plasma by the plasma gun.

In the negative ion generating device of the present invention, the plasma gun generates plasma inside the chamber, thereby generating negative ions inside the chamber. Then, a positive voltage is applied to the object by the voltage application unit, negative ions in the chamber are guided to the object side, and the negative ions are irradiated to the object. Here, after the generation of plasma by the plasma gun is stopped, electrons are likely to adhere to the raw material of negative ions, thereby generating negative ions. Therefore, the negative ions and electrons increase and decrease in the chamber, and the potential inside the chamber changes. Therefore, the appropriate timing for irradiating the negative ions to the object can be grasped from the measurement result of the potential measurement unit that measures the potential in the chamber. Therefore, the control unit controls the application of the voltage by the voltage application unit based on the measurement result of the potential measurement unit after the generation of the plasma by the plasma gun is stopped. Thus, the control unit can irradiate the negative ions to the object at a timing at which a large amount of electrons can be prevented from being irradiated to the object. As described above, the negative ions can be irradiated to the object at an appropriate timing.

The control unit may start the application of the voltage by the voltage application unit at a timing when the potential rises and then falls based on the measurement result of the potential measurement unit. The timing of the fall after the potential rise is a timing when the generation of negative ions proceeds to some extent after the generation of plasma is stopped. Therefore, the control unit can irradiate the negative ions to the object at the timing when the negative ions are generated by starting the application of the voltage at the timing.

The control unit may start the application of the voltage by the voltage application unit at a timing when the potential falls and reaches a peak of the fall, based on a measurement result of the potential measurement unit. The timing at which the potential drop reaches the peak is close to the timing at which the amount of generated negative ions becomes the peak after the generation of plasma is stopped. Therefore, the control unit can irradiate the negative ions to the object at a timing when there are many negative ions by starting the application of the voltage at the timing.

The control unit may start the application of the voltage by the voltage applying unit at a timing when the potential rises based on a measurement result of the potential measuring unit. In this case, more negative ions can be irradiated to the object than in the case where the application is started at the timing when the potential rises and then falls and the peak of the potential falls and reaches the fall. However, since there is a possibility that irradiation with a large amount of electrons is mixed, it is preferable to be an object that can allow electron irradiation, as compared with the case where application is started at a timing when the potential falls after rising and a timing when the potential falls and reaches a peak of the fall.

The potential measuring unit can measure the potential of the space around the object. In this case, control can be performed according to the situation in the vicinity of the object to be irradiated with negative ions.

The control unit repeats generation of plasma by the plasma gun and generation of negative ions based on stoppage of the generation of the plasma, the potential measuring unit measures a potential for each generation of negative ions, and the control unit controls application of voltage by the voltage applying unit based on a measurement result of the potential measuring unit. The voltage applied by the voltage applying unit affects the state of the plasma in the chamber. For example, even if the operating conditions for the 1 st generation of negative ions and the 2 nd generation of negative ions are the same, there is a case where the timing of generating negative ions after the plasma generation is stopped is changed between the two. Therefore, by controlling the measurement by the potential measuring section and the application of voltage based on the measurement result every time negative ions are generated, the negative ions can be irradiated to the object at an appropriate timing.

Effects of the invention

The present invention can provide an anion generator capable of irradiating an object with anions at an appropriate timing.

Drawings

Fig. 1 is a schematic cross-sectional view showing the structure of a film formation/negative ion generation device according to an embodiment of the present invention, and is a diagram showing an operation state in a film formation processing mode.

Fig. 2 is a schematic cross-sectional view showing the structure of the film formation/negative ion generation device of fig. 1, and is a view showing an operation state in a negative ion generation mode.

Fig. 3 is a flowchart showing the control contents of the control unit in the film formation/negative ion generation device according to the embodiment of the present invention.

In fig. 4, fig. 4(a) is a graph showing the floating potential at a predetermined position in the space of the vacuum chamber at the time of negative ion generation, and fig. 4(b) is a graph showing the number of negative ions per unit square area at a predetermined position in the space of the vacuum chamber.

Fig. 5 is a graph showing the state of the floating potential immediately after the generation of plasma is stopped.

Fig. 6 is a diagram showing a modification of the electrode unit of the potential measuring unit.

Fig. 7 is a flowchart showing the control contents of the control unit in the film formation/negative ion generation device according to the embodiment of the present invention.

Description of the symbols

1-film formation/negative ion generation device (negative ion generation device), 7-plasma gun, 10-vacuum chamber, 11-object to be film formed, 50-control section, 90-voltage application section, 110-potential measurement section, P-plasma.

Detailed Description

Hereinafter, a film deposition apparatus according to an embodiment of the present invention will be described with reference to the drawings.

In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

First, the structure of the film formation/negative ion generation device according to the embodiment of the present invention will be described with reference to fig. 1 and 2. Fig. 1 and 2 are schematic cross-sectional views showing the structure of the film formation/negative ion generation device according to the present embodiment. Fig. 1 shows an operation state in the film formation processing mode, and fig. 2 shows an operation state in the negative ion generation mode. The details of the film formation processing mode and the negative ion generation mode will be described later.

As shown in fig. 1 and 2, a film formation/negative ion generation apparatus 1 according to the present embodiment is an ion plating apparatus used for a so-called ion plating method. For convenience of explanation, fig. 1 and 2 show XYZ coordinate systems. The Y-axis direction is a direction in which an object to be film-formed, which will be described later, is conveyed. The X-axis direction is a direction in which the object to be film-formed faces a hearth mechanism described later. The Z-axis direction is a direction orthogonal to the Y-axis direction and the X-axis direction.

The film formation/negative ion generation apparatus 1 may be a so-called horizontal film formation/negative ion generation apparatus in which the object 11 to be film formed is placed in the vacuum chamber 10 and conveyed so that the thickness direction of the object 11 to be film formed is substantially perpendicular. In this case, the Z-axis and Y-axis directions are horizontal directions, and the X-axis direction is a vertical direction and a plate thickness direction. The film formation/negative ion generation apparatus 1 may be a so-called vertical film formation/negative ion generation apparatus in which the object 11 to be film formed is placed in the vacuum chamber 10 and conveyed in a state in which the object 11 to be film formed is upright or inclined from the upright state so that the direction of the thickness of the object 11 to be film formed is horizontal (the X-axis direction in fig. 1 and 2). In this case, the X-axis direction is a horizontal direction and a thickness direction of the film formation object 11, the Y-axis direction is a horizontal direction, and the Z-axis direction is a vertical direction. The film forming/negative ion generating apparatus according to an embodiment of the present invention will be described below by taking a horizontal film forming/negative ion generating apparatus as an example.

The film forming/negative ion generating apparatus 1 includes a vacuum chamber 10, a conveying mechanism 3, a film forming section 14, a negative ion generating section 24, a voltage applying section 90, a potential measuring section 110, and a control section 50.

The vacuum chamber 10 is a member for accommodating an object 11 to be film-formed and performing a film formation process. The vacuum chamber 10 includes a conveyance chamber 10a for conveying an object 11 to be film-formed, which is to be formed with a film of a film forming material Ma, a film forming chamber 10b for diffusing the film forming material Ma, and a plasma port 10c for receiving plasma P irradiated in a beam form from the plasma gun 7 into the vacuum chamber 10. The transfer chamber 10a, the film forming chamber 10b, and the plasma port 10c communicate with each other. The conveyance chamber 10a is set in a predetermined conveyance direction (arrow a in the figure) (Y axis). The vacuum chamber 10 is made of a conductive material and is connected to a ground potential.

The film forming chamber 10b includes, as a wall portion 10W: a pair of side walls along the conveying direction (arrow a), a pair of

side walls

10h, 10i along the direction (Z-axis direction) intersecting the conveying direction (arrow a), and a bottom wall 10j disposed so as to intersect the X-axis direction.

The conveyance mechanism 3 conveys the object-to-be-deposited holding member 16, which holds the object 11 to be deposited in a state facing the material Ma, in the conveyance direction (arrow a). For example, the object holding member 16 is a frame that holds the outer periphery of the object 11. The conveyance mechanism 3 is constituted by a plurality of conveyance rollers 15 provided in the conveyance chamber 10 a. The transport rollers 15 are arranged at equal intervals in the transport direction (arrow a), and transport in the transport direction (arrow a) while supporting the film formation object holding member 16. The object 11 to be film-formed is a plate-like member such as a glass substrate or a plastic substrate.

Next, the structure of the film forming section 14 will be described in detail. The film forming section 14 attaches particles of the film forming material Ma to the object 11 to be film formed by ion plating. The film forming section 14 includes a plasma gun 7, a steering coil 5, a hearth mechanism 2, and a ring hearth 6.

The plasma gun 7 is, for example, a pressure gradient type plasma gun, and a main body thereof is connected to the film forming chamber 10b through a plasma port 10c provided in a side wall of the film forming chamber 10 b. The plasma gun 7 generates plasma P in the vacuum chamber 10. The plasma P generated by the plasma gun 7 is emitted in a beam shape from the plasma port 10c into the film forming chamber 10 b. Thereby, plasma P is generated in the film forming chamber 10 b.

The plasma gun 7 is closed at one end by a cathode 60. A 1 st intermediate electrode (grid) 61 and a 2 nd intermediate electrode (grid) 62 are concentrically arranged between the cathode 60 and the plasma port 10 c. The 1 st intermediate electrode 61 incorporates a ring-shaped permanent magnet 61a for converging the plasma P. An electromagnet coil 62a for converging the plasma P is also built in the 2 nd intermediate electrode 62. The plasma gun 7 also functions as a negative ion generator 24 described later. The details of this will be described later in the description of the negative ion generator 24.

The steering coil 5 is provided around the plasma port 10c to which the plasma gun is attached. The turn coil 5 guides the plasma P into the film forming chamber 10 b. The steering coil 5 is excited by a power supply for the steering coil (not shown).

The hearth mechanism 2 holds the film forming material Ma. The crucible mechanism 2 is provided in the film forming chamber 10b of the vacuum chamber 10, and is disposed along the negative direction of the X-axis direction when viewed from the conveying mechanism 3. The hearth mechanism 2 includes a main hearth 17 as a main anode for guiding the plasma P emitted from the plasma gun 7 to the film forming material Ma or a main anode for guiding the plasma P emitted from the plasma gun 7.

The main furnace hearth 17 has a cylindrical filling portion 17a extending in the positive direction of the X-axis direction and filled with the film forming material Ma, and a flange portion 17b protruding from the filling portion 17 a. The main crucible 17 is held at a positive potential with respect to the ground potential of the vacuum chamber 10, and therefore, the plasma P of a negative potential is attracted. The filling portion 17a of the main furnace 17 into which the plasma P is incident has a through hole 17c for filling the film forming material Ma. The tip of the film forming material Ma is exposed to the film forming chamber 10b at one end of the through hole 17 c.

Examples of the film forming material Ma include a transparent conductive material such as ITO or ZnO, and an insulating sealing material such as SiON. When the film formation material Ma is made of an insulating material, when the main furnace 17 is irradiated with the plasma P, the main furnace 17 is heated by the current from the plasma P, and the leading end portion of the film formation material Ma is evaporated or sublimated, and the film formation material particles (evaporation particles) Mb ionized by the plasma P are diffused in the film formation chamber 10 b. When the film formation material Ma is made of a conductive material, when the main furnace 17 is irradiated with the plasma P, the plasma P is directly incident on the film formation material Ma, the front end portion of the film formation material Ma is heated and evaporated or sublimated, and the film formation material particles Mb ionized by the plasma P are diffused in the film formation chamber 10 b. The film forming material particles Mb diffused in the film forming chamber 10b move in the positive X-axis direction of the film forming chamber 10b, and adhere to the surface of the object 11 to be film formed in the transport chamber 10 a. The film forming material Ma is a solid formed into a cylindrical shape having a predetermined length, and a plurality of film forming materials Ma are charged into the hearth mechanism 2 at one time. Then, the film forming material Ma is extruded in order from the X-axis negative side of the hearth mechanism 2 in accordance with the consumption of the film forming material Ma so that the front end portion of the film forming material Ma on the forefront side is kept in a predetermined positional relationship with the upper end of the main hearth 17.

The ring hearth 6 is an auxiliary anode having an electromagnet for inducing the plasma P. The ring hearth 6 is disposed around the filling portion 17a of the main hearth 17 that holds the film forming material Ma. The ring hearth 6 includes an annular coil 9, an annular permanent magnet portion 20, and an annular container 12, and the coil 9 and the permanent magnet portion 20 are accommodated in the container 12. In the present embodiment, the coil 9 and the permanent magnet section 20 are provided in this order in the X-axis negative direction when viewed from the conveyance mechanism 3, but the permanent magnet section 20 and the coil 9 may be provided in this order in the X-axis negative direction. The ring hearth 6 controls the orientation of the plasma P incident on the film forming material Ma or the orientation of the plasma P incident on the main hearth 17 according to the magnitude of the current flowing through the coil 9.

Next, the structure of the negative ion generator 24 will be described in detail. The negative ion generating unit 24 includes the plasma gun 7, the raw material gas supply unit 40, and the circuit unit 34. Further, a part of the components of the control unit 50 also functions as the negative ion generating unit 24. The functions of a part of the control unit 50 and the circuit unit 34 also belong to the film forming unit 14.

The plasma gun 7 is the same as the plasma gun 7 provided in the film forming section 14. That is, in the present embodiment, the plasma gun 7 of the film forming section 14 also serves as the plasma gun 7 of the negative ion generating section 24. The plasma gun 7 functions as the film forming section 14 and also functions as the negative ion generating section 24. Further, the film forming section 14 and the negative ion generating section 24 may have separate plasma guns different from each other.

The plasma gun 7 intermittently generates plasma P in the film forming chamber 10 b. Specifically, the plasma gun 7 is controlled by a control unit 50 described later so as to intermittently generate plasma P in the film forming chamber 10 b. This control will be described later in the description of the control unit 50 to be described later.

The raw material gas supply unit 40 is disposed outside the vacuum chamber 10. The raw material gas supply unit 40 supplies a raw material gas into the vacuum chamber 10 through a gas supply port 41 provided in a side wall (for example, side wall 10h) of the film forming chamber 10 b. As the raw material gas, for example, oxygen gas, which is a raw material gas of oxygen anions, or the like can be used. The source gas supply unit 40 starts the supply of oxygen gas when, for example, the film formation processing mode is switched to the negative ion generation mode. The source gas supply unit 40 may continue to supply oxygen gas in both the film formation process mode and the negative ion generation mode.

The position of the gas supply port 41 is preferably a position near the boundary between the film forming chamber 10b and the transport chamber 10 a. At this time, since the oxygen gas from the raw material gas supply unit 40 can be supplied to the vicinity of the boundary between the film forming chamber 10b and the transport chamber 10a, negative ions to be described later are generated in the vicinity of the boundary. Therefore, the generated negative ions can be favorably attached to the object 11 to be film-formed in the transfer chamber 10 a. The position of the gas supply port 41 is not limited to the vicinity of the boundary between the film forming chamber 10b and the transfer chamber 10 a.

The circuit unit 34 includes a variable power source 80, a 1 st wiring 71, a 2 nd wiring 72, resistors R1 to R4, and short-circuit switches SW1 and SW 2.

The variable power supply 80 applies a negative voltage to the cathode 60 of the plasma gun 7 and a positive voltage to the main hearth 17 of the hearth mechanism 2 across the vacuum chamber 10 at the ground potential. Thereby, the variable power source 80 generates a potential difference between the cathode 60 of the plasma gun 7 and the main hearth 17 of the hearth mechanism 2.

The 1 st wire 71 electrically connects the cathode 60 of the plasma gun 7 and the negative potential side of the variable power supply 80. The 2 nd wire 72 electrically connects the main hearth 17 (anode) of the hearth mechanism 2 and the positive potential side of the variable power supply 80.

One end of the resistor R1 is electrically connected to the 1 st intermediate electrode 61 of the plasma gun 7, and the other end is electrically connected to the variable power supply 80 via the 2 nd wiring 72. That is, the resistor R1 is connected in series between the 1 st intermediate electrode 61 and the variable power supply 80.

One end of the resistor R2 is electrically connected to the 2 nd intermediate electrode 62 of the plasma gun 7, and the other end is electrically connected to the variable power supply 80 via the 2 nd wiring 72. That is, the resistor R2 is connected in series between the 2 nd intermediate electrode 62 and the variable power supply 80.

One end of the resistor R3 is electrically connected to the wall portion 10W of the film forming chamber 10b, and the other end is electrically connected to the variable power supply 80 via the 2 nd wiring 72. That is, the resistor R3 is connected in series between the wall portion 10W of the film forming chamber 10b and the variable power source 80.

One end of the resistor R4 is electrically connected to the ring furnace cylinder 6, and the other end is electrically connected to the variable power source 80 via the 2 nd wiring 72. That is, the resistor R4 is connected in series between the ring furnace cylinder 6 and the variable power source 80.

The short-circuit switches SW1 and SW2 are switching units that are switched on/off by receiving an instruction signal from the control unit 50.

The short-circuit switch SW1 is connected in parallel with the resistor R2. The short-circuit switch SW1 is switched between on and off by the control unit 50 depending on whether the film formation processing mode or the negative ion generation mode is set. Here, the film formation process mode is a mode for performing a film formation process on the object 11 to be film-formed in the vacuum chamber 10. The negative ion generation mode is a mode in which negative ions are generated in the vacuum chamber 10 so as to adhere to the surface of the film formed on the object 11 to be film-formed. The short switch SW1 is turned off in the film formation processing mode. Thus, in the film formation processing mode, the 2 nd intermediate electrode 62 and the variable power supply 80 are electrically connected to each other via the resistor R2, and thus a current is less likely to flow between the 2 nd intermediate electrode 62 and the variable power supply 80. As a result, the plasma P from the plasma gun 7 is emitted into the vacuum chamber 10 and is incident on the film forming material Ma (see fig. 1). In addition, when the plasma P from the plasma gun 7 is emitted into the vacuum chamber 10, instead of making it difficult for the current to flow to the 2 nd intermediate electrode 62, it is possible to make it difficult for the current to flow to the 1 st intermediate electrode 61. At this time, the short-circuit switch SW1 is connected to the 1 st intermediate electrode 61 side instead of the 2 nd intermediate electrode 62 side.

On the other hand, in the negative ion generation mode, the short-circuit switch SW1 intermittently generates the plasma P from the plasma gun 7 in the vacuum chamber 10, and therefore, the on/off state is switched at predetermined intervals by the control unit 50. When the short-circuit switch SW1 is switched to the on state, the electrical connection between the 2 nd intermediate electrode 62 and the variable power supply 80 is short-circuited, and thus a current flows between the 2 nd intermediate electrode 62 and the variable power supply 80. That is, a short-circuit current flows to the plasma gun 7. As a result, the plasma P from the plasma gun 7 is not emitted into the vacuum chamber 10.

When the short-circuit switch SW1 is switched to the off state, the 2 nd intermediate electrode 62 and the variable power supply 80 are electrically connected to each other via the resistor R2, and thus current is hard to flow between the 2 nd intermediate electrode 62 and the variable power supply 80. As a result, the plasma P from the plasma gun 7 is emitted into the vacuum chamber 10. In this way, the controller 50 switches the on/off state of the short-circuit switch SW1 at predetermined intervals, thereby intermittently generating the plasma P from the plasma gun 7 in the vacuum chamber 10. That is, the short-circuit switch SW1 is a switching unit that switches between supply and interruption of the plasma P in the vacuum chamber 10.

The short-circuit switch SW2 is connected in parallel with the resistor R4. The on/off state of the short-circuit switch SW2 is switched by the control unit 50 depending on whether the film formation processing mode is a standby mode, which is a state before the film formation object 11 is conveyed before the film formation processing mode, or the film formation processing mode. The short-circuit switch SW2 is turned on in the standby mode. Accordingly, since the electrical connection between the ring hearth 6 and the variable power source 80 is short-circuited, the current flows more easily to the ring hearth 6 than to the main hearth 17, and thus the film forming material Ma can be prevented from being unnecessarily consumed.

On the other hand, the short-circuit switch SW2 is turned off in the film formation processing mode. Accordingly, since the ring hearth 6 and the variable power supply 80 are electrically connected via the resistor R4, the current flows more easily to the main hearth 17 than to the ring hearth 6, and the emission direction of the plasma P can be favorably directed toward the film forming material Ma. In addition, the short-circuit switch SW2 can be in either an on state or an off state in the negative ion generation mode.

The voltage applying unit 90 can apply a positive voltage to the film formation object (object) 11 after film formation. The voltage applying unit 90 includes the bias circuit 35 and the trolley wire 18.

The bias circuit 35 is a circuit for applying a positive bias voltage to the film formation object 11 after film formation. The bias circuit 35 includes a bias power supply 27 for applying a positive bias voltage (hereinafter, simply referred to as "bias voltage") to the object 11, a 3 rd wire 73 for electrically connecting the bias power supply 27 and the trolley wire 18, and a short-circuit switch SW3 provided on the 3 rd wire 73. The bias power supply 27 applies a voltage signal (periodic electric signal) of a rectangular wave that periodically increases or decreases as a bias voltage. The bias power supply 27 is configured to be able to change the frequency of the applied bias voltage by the control of the control unit 50. One end of the 3 rd wiring 73 is connected to the positive potential side of the bias power supply 27, and the other end is connected to the trolley wire 18. Thereby, the 3 rd wiring 73 electrically connects the trolley wire 18 and the bias power supply 27.

The short-circuit switch SW3 is connected in series between the trolley wire 18 and the positive potential side of the bias power supply 27 through the 3 rd wiring 73. The short-circuit switch SW3 is a switching unit that switches whether or not a bias voltage is applied to the trolley wire 18. The short-circuit switch SW3 is switched in its on/off state by the control section 50. The short-circuit switch SW3 is turned on at a predetermined timing in the negative ion generation mode. When the short-circuit switch SW3 is turned on, the trolley wire 18 and the positive potential side of the bias power supply 27 are electrically connected to each other, and a bias voltage is applied to the trolley wire 18.

On the other hand, the short-circuit switch SW3 is turned off at a predetermined timing in the film formation processing mode and the negative ion generation mode. When the short-circuit switch SW3 is turned off, the trolley wire 18 and the bias power supply 27 are electrically disconnected from each other, and no bias voltage is applied to the trolley wire 18. The timing of applying the bias voltage will be described later in detail.

The trolley wire 18 is a wire for supplying power to the film formation object holding member 16. The trolley wire 18 extends in the conveying direction (arrow B) in the conveying chamber 10 a. The trolley wire 18 is in contact with a power supply brush 42 provided on the film formation object holding member 16, and thereby power is supplied to the film formation object holding member 16 through the power supply brush 42. The trolley wire 18 is made of, for example, a stainless steel wire or the like.

The potential measuring unit 110 measures the potential in the vacuum chamber 10. The potential measuring unit 110 measures the potential of the space around the object 11. The potential measuring unit 110 includes a potential detecting unit 111 and an electrode unit 112. The potential detection unit 111 is electrically connected to the electrode unit 112. The potential detection section 111 detects a value of a floating potential at a position where the electrode section 112 is provided, from the potential of the electrode section 112. The potential detection unit 111 transmits the detected value to the control unit 50 as a measurement value.

The electrode portion 112 is a member that enters the internal space from the outside of the vacuum chamber 10. The electrode 112 is disposed at a position not interfering with the moving object holding member 16. The front end 112a of the electrode 112 is disposed in a space around the object 11. The front end 112a of the electrode 112 is disposed in the transfer chamber 10a of the vacuum chamber 10. The distal end portion 11a is disposed in the vicinity of a communicating portion between the conveyance chamber 10a and the film formation chamber 10b and at substantially the same position as the object to be film-formed 11 in the Z-axis direction.

In addition, the electrode portion 112 may be covered with an insulating member except for the front end portion 112 a. For example, as shown in fig. 6, the region of the electrode portion 112 inside the wall portion of the vacuum chamber 10 may be covered with an insulating member 140. Only the distal end portion 112a may be exposed from the insulating member 140 to the space of the vacuum chamber 10. In this case, since the floating potential is not detected except for the tip portion 112a, the potential at a desired position can be measured in a concentrated manner.

The control unit 50 controls the entire film formation/negative ion generation apparatus 1, and is composed of a CPU, a RAM, a ROM, an input/output interface, and the like. The controller 50 is disposed outside the vacuum chamber 10. The control unit 50 includes a mode switching unit 51 for switching between a film formation processing mode and a negative ion generation mode, a plasma control unit 52 for controlling generation of the plasma P by the plasma gun 7, and a voltage control unit 53 for controlling application of a voltage by the voltage application unit 90.

When the mode switching unit 51 of the control unit 50 is set to the negative ion generation mode, the control unit 50 controls the raw material gas supply unit 40 to supply oxygen gas into the film forming chamber 10 b. Next, the plasma control unit 52 of the control unit 50 controls the plasma gun 7 so as to intermittently generate the plasma P from the plasma gun 7 in the film forming chamber 10 b. For example, the control unit 50 intermittently generates the plasma P from the plasma gun 7 in the film forming chamber 10b by switching the on/off state of the short-circuit switch SW1 at predetermined intervals.

When the short-circuit switch SW1 is turned on, the plasma P from the plasma gun 7 is not emitted into the film forming chamber 10b, and therefore the electron temperature of the plasma P in the film forming chamber 10b is rapidly lowered. Therefore, the electrons of the plasma P are likely to adhere to the particles of the oxygen gas supplied into the film forming chamber 10b in the raw material gas supply step S21. Thereby, negative ions are efficiently generated in the film forming chamber 10 b.

The control unit 50 stops the generation of the plasma P by the plasma gun 7, and then controls the application of the voltage by the voltage application unit 90 based on the measurement result of the potential measurement unit 110. The control unit 50 starts voltage application by the voltage application unit 90 at a predetermined timing based on the measurement result of the potential measurement unit 110. The timing for starting the application of the voltage by the voltage application unit 90 is set in advance by the control unit 50.

Here, the relationship between the generation of the plasma P and the generation of the negative ions will be described with reference to fig. 4 and 5. The solid line in fig. 4(a) is a graph showing the floating potential at a predetermined position in the space of the vacuum chamber 10 at the time of negative ion generation. The floating potential rises as electrons or negative ions in the vacuum chamber 10 increase, and falls as electrons or negative ions in the vacuum chamber 10 decrease. Fig. 4(b) shows the number of negative ions per unit square area at a predetermined position in the space of the vacuum chamber 10. Fig. 5 is a graph showing the state of the floating potential immediately after the generation of plasma is stopped. In fig. 4, the generation of the plasma P is started at time "0", and the generation of the plasma is stopped at time "t 1". As shown in fig. 4(a), the floating potential rises sharply at the moment when the plasma P is stopped. As shown in fig. 4(b), after stopping the plasma P, the amount of negative ions rapidly decreases, then increases greatly at time t3, and reaches a rising peak at time t 2. At a time corresponding to time t3 of fig. 4(a), the floating potential reaches a peak of rising and then falls.

As shown in fig. 5, after the plasma P stops, the floating potential rises rapidly in the interval E1 and gradually in the interval E2. The floating potential reaches a peak of rising near time t3, and then falls in an interval E3. The floating potential after the fall reaches a peak of the fall near time t2, and then, after interval E4, the floating potential rises gradually. The interval E3 is also an interval in which the amount of negative ions increases sharply (see fig. 4 (b)). In the interval E3, the amount of negative ions increases and the floating potential decreases, and therefore, the interval is considered to be an interval in which the amount of electrons decreases.

From time t1 to time t3, Ar plasma (Ar) remains in the vacuum chamber 10⁺，e^-). This is because, even if the short-circuit switch SW1 is short-circuited, the voltage between the main hearth 17 and the 2 nd intermediate electrode 62 is positive. For example, with Ar⁺+e^-→ e of Ar extinction, flows into the vacuum chamber 10 and the potential measuring section 110^-The amount of (c) is reduced. On the other hand, if the electron temperature is decreased (O)₂Is O₂Active state of) then O is carried out₂*+e^-→O^-+ O (dissociative electron attachment), O + e^-→O^-(electron attachment) and the like to form O having a lower speed than that of electrons^-。e^-And O^-Faster than it does, and therefore flows into the vacuum chamber 10, but O^-The velocity is slower and therefore the diffusion is at the rate of the gas temperature. Since there is a potential difference between the main hearth 17 and the 2 nd intermediate electrode 62 until time t3, e^-And O^-Is pulled toward the plasma P side in the vacuum chamber 10, and the pulling force disappears after time t3, so that e^-And O^-And (4) diffusion. e.g. of the type^-And O^-Are in greater difference, and therefore are slower^-Is left in the O^-With a negative charge. O is^-Generation of and Ar⁺+e^-→Ar、O⁺+e^-→O、O₂ ⁺+e^-→O₂Ee of etc^-The extinction proceeds simultaneously, showing the behavior of the floating potential as shown in fig. 4. Considering the balance between plasma generation and extinction, and considering e^-In case of conflict of (1), only O^-And O₂ ^-Survive the negative charge. O is^-90% or more, and therefore, it is substantially O^-. Therefore, even if the plasma P is turned off, that is, the electron supply is lost, the negatively charged one is O due to the above-mentioned condition^-。

The control unit 50 starts the application of the voltage by the voltage application unit 90 at a timing when the potential rises and then falls based on the measurement result of the potential measurement unit 110. In the example shown in fig. 5, the intervals in which the potential rises are interval E1 and interval E2. The potential drop interval is interval E3. Voltage controller 53 of controller 50 starts application of the voltage by voltage applicator 90 at any timing in section E3 (including time t3 at which the peak value of the drop occurs). In the section E3, the voltage control unit 53 of the control unit 50 may start the application of the voltage by the voltage application unit 90 in the region on the second half side where the generation of negative ions proceeds to some extent. The voltage control unit 53 of the control unit 50 may start to apply the voltage at a timing when the potential reaches the predetermined threshold value in the section E3.

The control unit 50 may start the application of the voltage by the voltage application unit 90 at a timing when the potential falls and reaches a peak of the fall, based on the measurement result of the potential measurement unit 110. That is, the voltage control unit 53 of the control unit 50 starts the application of the voltage by the voltage application unit 90 at the timing when the peak P1 of the drop in the floating potential is reached. The control unit 50 monitors the amount of change in potential based on the measurement result from the potential measuring unit 110, and thereby recognizes that the potential has reached the peak P1 of the drop. The timing of starting the application of the voltage does not need to completely coincide with the timing at which the potential measured by the potential measuring unit 110 becomes the peak value P1, but may be a timing shifted from the timing at which the potential becomes the peak value P1.

The control unit 50 may start the application of the voltage by the voltage application unit 90 at a timing when the potential rises, based on the measurement result of the potential measurement unit 110. Voltage controller 53 of controller 50 starts application of the voltage by voltage applicator 90 at the timing of interval E1 or interval E2. The voltage control unit 53 of the control unit 50 may start the application of the voltage by the voltage application unit 90 at the timing of the interval E2 after a certain time has elapsed from the stop of the plasma P.

Next, a part of the control content in the negative ion generation by the control unit 50 will be described with reference to a flowchart shown in fig. 3. The processing of the control unit 50 is not limited to fig. 3.

As shown in fig. 3, the plasma control unit 52 of the control unit 50 starts generation of the plasma P by the plasma gun 7 (step S10). After a predetermined time has elapsed, the plasma control unit 52 of the control unit 50 stops the generation of the plasma P by the plasma gun 7 (step S20). As a result, the floating potential changes in the vacuum chamber 10 as shown in fig. 5. The voltage control unit 53 of the control unit 50 acquires the measurement result from the potential measurement unit 110 (step S30). Next, voltage control unit 53 of control unit 50 determines whether or not it is timing to start application of the voltage by voltage application unit 90, based on the potential acquired in S30 (step S40).

If it is determined at S40 that the timing is not the timing of voltage application, the process is repeated again from S30. On the other hand, when it is determined at S40 that the timing is the voltage application timing, the voltage control unit 53 of the control unit 50 starts the voltage application. Thus, by applying a positive bias voltage to the object 11, negative ions in the vacuum chamber 10 are guided to the object 11.

Fig. 3 illustrates the generation of negative ions in one time in the negative ion generation mode, that is, the generation of plasma P by the plasma gun 7 and the processing in one time for stopping the generation of plasma P. The film forming/negative ion generating apparatus 1 performs negative ion generation a plurality of times. That is, the control unit 50 repeats the generation of the plasma P by the plasma gun 7 and the generation of negative ions based on the stop of the generation of the plasma P. Therefore, the control content of the control unit 50 when the negative ions are repeatedly generated will be described with reference to fig. 7. At this time, the potential measuring unit 110 measures the potential each time the negative ions are generated, and the control unit 50 controls the application of the voltage by the voltage applying unit 90 based on the measurement result of the potential measuring unit 110.

As shown in fig. 7, the same processing as in fig. 3 is performed up to S10 to S50. After S50, controller 50 stops applying the voltage by voltage applicator 90 after a predetermined time has elapsed (step S60). Next, the control unit 50 determines whether or not the negative ion irradiation is ended (step S70). When it is determined at S70 that the negative ion irradiation is ended, the processing shown in fig. 7 is ended. When it is determined at S70 that the negative ion irradiation has not been completed, the process is repeated again from S10. That is, the controller 50 generates the plasma P again (step S10), and stops the generation of the plasma P (step S20). At this time, the measurement by the potential measuring unit 110 is continued, and the control unit 50 acquires the measurement result from the potential measuring unit 110 (step S30). Then, the control unit 50 resumes the application of the voltage by the voltage application unit 90 based on the measurement result of the potential measurement unit 110 (step S40). In this manner, when negative ions are generated, the measurement by the potential measuring unit 110 and the voltage application by the voltage applying unit 90 are repeated each time.

The operation and effect of the film forming/negative ion generating apparatus 1 of the present embodiment will be described.

In the film formation/negative ion generation apparatus 1, the plasma gun 7 generates plasma P inside the vacuum chamber 10, thereby generating negative ions inside the vacuum chamber 10. Then, the voltage applying unit 90 applies a positive voltage to the object 11, and negative ions in the vacuum chamber 10 are guided to the object 11 side, so that the negative ions are irradiated to the object 11. Here, after the generation of the plasma P by the plasma gun 7 is stopped, electrons are likely to adhere to the raw material of negative ions, and the negative ions are generated. Therefore, the negative ions and electrons increase and decrease in the vacuum chamber 10, and thus the potential inside the vacuum chamber 10 varies. Therefore, the measurement result of the potential measuring unit 110 that measures the potential in the vacuum chamber 10 can determine the appropriate timing for irradiating the object 11 with negative ions. Therefore, the control unit 50 stops the generation of the plasma P by the plasma gun 7, and then controls the application of the voltage by the voltage application unit 90 based on the measurement result of the potential measurement unit 110. Thus, the control unit 50 can irradiate the negative ions to the object 11 at a timing at which a large amount of electrons can be prevented from being irradiated to the object. As described above, the negative ions can be irradiated to the object 11 to be film-formed at an appropriate timing.

The control unit 50 may start the application of the voltage by the voltage application unit 90 at a timing when the potential rises and then falls based on the measurement result of the potential measurement unit 110. The timing of the fall after the potential rise is the timing when the generation of negative ions proceeds to some extent after the generation of plasma P is stopped. Therefore, the control unit 50 can irradiate the negative ions to the object 11 at the timing when the negative ions are generated by starting the application of the voltage at the timing.

The control unit 50 may start the application of the voltage by the voltage application unit 90 at a timing when the potential falls and reaches a peak of the fall, based on the measurement result of the potential measurement unit 110. The timing to reach the peak of the drop in potential is close to the timing at which the amount of generated negative ions becomes a peak after the generation of the plasma P is stopped. Therefore, the control unit can irradiate the negative ions to the object 11 at a timing when there are many negative ions by starting the application of the voltage at this timing.

The control unit 50 can start the application of the voltage by the voltage application unit 90 at the timing of the potential rise based on the measurement result of the potential measurement unit 110. In this case, more negative ions can be irradiated to the object than in the case where the application is started at the timing when the potential rises and then falls and at the timing when the potential falls and then reaches the peak of the fall. However, since there is a possibility that irradiation with a large amount of electrons is mixed, it is preferable to be an object that can allow electron irradiation, as compared with the case where application is started at the timing when the potential rises and then falls and the timing when the potential falls and reaches the peak of the fall.

The potential measuring unit 110 can measure the potential of the space around the object 11. In this case, control can be performed according to the situation in the vicinity of the object 11 to be film-formed, which is the object to be irradiated with negative ions.

The control unit 50 repeats the generation of the plasma P by the plasma gun 7 and the generation of negative ions based on the stop of the generation of the plasma P, and the potential measuring unit 110 measures the potential for each generation of negative ions, and the control unit 50 controls the application of voltage by the voltage applying unit 90 based on the measurement result of the potential measuring unit 110. The voltage application by the voltage application unit 90 affects the state of the plasma P in the vacuum chamber 10. For example, even if the operating conditions for the 1 st generation of negative ions and the 2 nd generation of negative ions are the same, there is a case where the timing of generating negative ions changes after the generation of plasma P is stopped. For example, there is a case where electrons at the 2 nd time are reduced compared to the 1 st time. After the timing of voltage application is determined based on the measurement result of the potential measuring unit 110 at the time of negative ion generation for the 1 st time, when voltage application is performed at the time of negative ion generation for the second time or later at the same timing, negative ion irradiation may not be performed at an appropriate timing (however, this control method is not excluded from the scope of claim 1). Therefore, as shown in fig. 7, by performing control of measurement by the potential measuring unit 110 and application of voltage based on the measurement result every time negative ions are generated, the object can be irradiated with negative ions at an appropriate timing.

Here, when the voltage value of the voltage application is changed in the negative ion irradiation, the state of the plasma P is changed, and when the voltage value is high, electrons increase. In each generation of negative ions, when the potential measuring unit 110 measures the potential, the influence of the change in the voltage value applied by the voltage application can be reflected in the control. This can cope with a case where the irradiation amount of negative ions and the incident energy are changed during the process.

While one embodiment of the present embodiment has been described above, the present invention is not limited to the above embodiment, and may be modified and applied to other embodiments without departing from the spirit of the invention described in the claims.

In the above embodiment, the ion plating type film deposition apparatus and the negative ion generator are combined, and therefore the plasma P emitted from the plasma gun is guided to the main furnace. However, the negative ion generating apparatus may not be combined with the film forming apparatus. Therefore, the plasma P can be guided to, for example, an electrode or the like of a wall portion opposed to the plasma gun.

For example, although the plasma gun 7 is a pressure gradient type plasma gun in the above embodiment, the plasma gun 7 is not limited to a pressure gradient type plasma gun as long as it can generate plasma in the vacuum chamber 10.

In the above embodiment, the set of the plasma gun 7 and the hearth mechanism 2 is provided only one set in the vacuum chamber 10, but a plurality of sets may be provided. Further, the plasma P can be supplied from the plurality of plasma guns 7 to one material. In the above embodiment, the annular hearth 6 is provided, but the annular hearth 6 may be omitted by devising the orientation of the plasma gun 7 and the position or orientation of the material in the hearth mechanism 2.

Claims

1. An anion generating apparatus for generating anions using plasma and irradiating the anions to an object, the anion generating apparatus comprising:

a chamber for accommodating the object and generating the negative ions therein;

a plasma gun generating the plasma within the chamber;

a potential measuring unit for measuring a potential in the chamber;

a voltage applying unit capable of applying a positive voltage to the object; and

a control unit for controlling the negative ion generator,

the control unit controls the application of the voltage by the voltage application unit based on the measurement result of the potential measurement unit after the generation of the plasma by the plasma gun is stopped.

2. The negative ion generating apparatus according to claim 1,

the control unit starts the application of the voltage by the voltage application unit at a timing when the potential rises and falls based on the measurement result of the potential measurement unit.

3. The negative ion generating apparatus according to claim 2,

the control unit starts the application of the voltage by the voltage application unit at a timing when the potential decreases and reaches a peak of the decrease, based on a measurement result of the potential measurement unit.

4. The negative ion generating apparatus according to claim 1,

the control unit starts the application of the voltage by the voltage application unit at a timing when the potential rises based on the measurement result of the potential measurement unit.

5. The negative ion generation device according to any one of claims 1 to 4,

the potential measuring unit measures a potential of a space around the object.

6. The negative ion generation device according to any one of claims 1 to 5,

the control unit repeats the generation of the plasma by the plasma gun and the generation of the negative ions based on the stop of the generation of the plasma,

the potential measuring unit measures the potential each time the negative ions are generated, and the control unit controls the application of the voltage by the voltage applying unit based on the measurement result of the potential measuring unit.