Plasma gun, film forming device and negative ion generating device

Abstract

The present invention provides a plasma gun, a film forming device and a negative ion generating device that can stabilize discharge while suppressing the attachment of impurities to an electrode. A plasma gun according to one embodiment includes a cathode tube (80), wherein the cathode tube (80) includes: an outer tube (83) with one end open; a main cathode (84) disposed inside the outer tube (83); a cover (87) mounted on one end side of the outer tube (83) and having an opening (871) smaller than the cross-sectional size of one end of the outer tube (83); and a material of the cover (87) including the same material as that of the main cathode (84).

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2020-128098 filed on Jul. 29, 2020. The entire contents of the Japanese Patent Application are incorporated herein by reference.

[0002] The invention relates to a plasma gun, a film forming device and a negative ion generating device. Background Art

[0003] Patent document 1 describes a plasma gun assembled in a film forming device. The plasma gun includes an intermediate electrode including a first intermediate electrode and a second intermediate electrode and a cathode flange to which a cathode tube is fixed. The cathode tube includes an outer Mo tube and an inner Ta tube. The Mo tube and the Ta tube are both fixed to the cathode flange. If argon gas is supplied to the inside of the cathode tube, a plasma beam is generated by the collision of accelerated electrons and argon gas. The plasma beam passes through a hole formed in the center of the first intermediate electrode and the second intermediate electrode and is radiated into the film forming chamber.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2008-305724

[0005] As the material of the cover of the cathode tube, a high melting point material different from the electrode material, such as tungsten (W) or molybdenum (Mo), can be used. When the aforementioned plasma beam is generated, the gas ionized by the electrons released from the electrode is accelerated by a high voltage and collides with the cover of the cathode tube inside the cathode tube. At this time, the material of the cover of the cathode tube may be sputtered and attached to the electrode. If the material of the cover different from the electrode is attached to the electrode, the material sublimates or forms a film and is mixed into the film as an impurity, which may cause product defects. In addition, if impurities are attached to the electrode, the discharge may be unstable due to the attachment of the impurities, and it may be necessary to perform inspection and maintenance work at short intervals to manage the impurities. Summary of the invention

[0006] An object of the present invention is to provide a plasma gun, a film forming device, and a negative ion generating device that can stabilize discharge while suppressing the adhesion of impurities to electrodes.

[0007] A plasma gun according to one aspect of the present invention includes a cathode tube, wherein the cathode tube has: an outer tube having one end open; an electrode arranged inside the outer tube; and a cover body installed on one end side of the outer tube and having an opening smaller than the cross-sectional size of the one end of the outer tube, and the material of the cover body includes the same material as that of the electrode.

[0008] In this plasma gun, an electrode is arranged inside an outer cylinder which is open at one end, and a cover body with an opening is installed on the one end of the outer cylinder. The opening diameter of the cover body is smaller than the opening diameter of the outer cylinder, and the material of the cover body includes the same material as the material of the electrode. Therefore, even if the material of the cover body of the cathode tube adheres to the electrode, the amount of impurities attached to the electrode can be reduced by the material of the cover body including the material of the electrode. Therefore, it is possible to suppress the mixing of impurities into the film and the generation of product defects. Moreover, even if the material of the cover body including the material of the electrode adheres to the electrode, it is possible to prevent the discharge from becoming unstable. In addition, the cover body can function as an electrode by including the material of the electrode in the material of the cover body. Therefore, the surface area of ​​the part functioning as the electrode can be increased, and thus the discharge power can be increased. Therefore, a larger current than before can flow.

[0009] The cover may be made of the same material as the electrode. In this case, since the cover is made of the electrode material, it is possible to stabilize the discharge while preventing impurities from adhering to the electrode. In addition, the discharge power can be further increased to allow a larger current to flow.

[0010] The cover may be made of lanthanum hexaboride (LaB6). In this case, since the cover is made of LaB6, more electrons can be released. Thus, the cover can be used as a hot electron generation source, so a larger current can flow.

[0011] One aspect of the present invention relates to a film forming device, which has a plasma gun with a cathode tube, wherein the cathode tube includes: an outer tube with one end open; an electrode arranged inside the outer tube; and a cover body installed on one end side of the outer tube and having an opening smaller than the cross-sectional size of one end of the outer tube, and the material of the cover body includes the same material as that of the electrode.

[0012] In the film forming device, an electrode is provided inside an outer cylinder of a plasma gun which is open at one end, and a cover body with an opening is mounted on the one end of the outer cylinder, and the material of the cover body includes the same material as the material of the electrode. Therefore, as in the aforementioned plasma gun, even if the material of the cover body of the cathode tube adheres to the electrode, the amount of impurities adhering to the electrode can be reduced by the material of the cover body including the material of the electrode. As a result, the same effect as in the aforementioned plasma gun can be obtained.

[0013] One aspect of the present invention relates to a negative ion generating device, which is used to irradiate negative ions to an object. The negative ion generating device has a plasma source, which supplies plasma into a vacuum chamber. The plasma source has: an outer tube, one end of which is open; an electrode, which is arranged inside the outer tube; and a cover body, which is installed on one end side of the outer tube and has an opening with a cross-sectional size smaller than that of one end of the outer tube, and the material of the cover body includes the same material as that of the electrode.

[0014] In the negative ion generating device, an electrode is provided inside an outer cylinder of a plasma source which is open at one end, and a cover body with an opening is installed on the one end of the outer cylinder, and the material of the cover body includes the same material as the material of the electrode. Thus, as in the aforementioned plasma gun, even if the material of the cover body adheres to the electrode, the amount of impurities adhering to the electrode can be reduced by the material of the cover body including the material of the electrode. As a result, the same effect as in the aforementioned plasma gun can be obtained.

[0015] The negative ion generating device may include a control unit that controls the plasma source so that the plasma source generates plasma intermittently. In this case, the plasma source can be caused to generate plasma intermittently.

[0016] Effect of the invention:

[0017] According to the present invention, it is possible to stabilize discharge while suppressing adhesion of impurities to electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a film forming apparatus according to one embodiment.

[0019] Figure 2 This is a cross-sectional view illustrating the structure of a plasma gun.

[0020] Figure 3 This is a cross-sectional view illustrating the structure of a cathode tube.

[0021] Figure 4 This is a graph showing an example of the relationship between temperature and current density.

[0022] Figure 5 This is a graph showing the melting point, current density, and work function of each material.

[0023] Figure 6 This is a schematic structural diagram of a film forming device including a negative ion generating device according to one embodiment.

[0024] In the figure: 1, 101-film forming device, 2-furnace mechanism, 3-conveying mechanism, 6, 106-ring furnace, 6a-coil, 6b-permanent magnet, 7-plasma gun, 8-pressure adjustment device, 10-chamber, 10a-conveying part, 10b-film forming part, 10c, 110c-plasma port, 11-film-forming object, 12-steering coil, 15, 115-conveying roller, 16-film-forming object holding part, 21-main furnace, 70-intermediate electrode, 71-first intermediate electrode, 72-second intermediate Electrode, 73-sealing gasket, 74-hollow coil, 75-permanent magnet, 80-cathode tube, 81-auxiliary electrode, 82-tube seat, 83-outer cylinder, 84-main cathode (electrode), 85-first supporting member, 86-second supporting member, 87-cover, 88-third supporting member, 90-cathode flange, 92-glass tube, 103-non-single crystal substrate, 107-plasma source, 109-coil, 110-vacuum chamber, 110a-transport chamber, 110b-film forming chamber, 110h-side wall , 110i-side wall, 110j-bottom wall, 110w-wall, 112-container, 113-transport mechanism, 114-film forming part, 116-non-single crystal substrate holding part, 117-main furnace, 117a-filling part, 117b-flange part, 117c-through hole, 120-permanent magnet part, 122-furnace mechanism, 124-negative ion generating device, 125-steering coil, 130-magnetic field generating coil, 130a, 130b-coil, 134-circuit part, 140-original Material gas supply part, 141-gas supply port, 150-control part, 160-electrode, 161, 162-intermediate electrodes, 161a-annular permanent magnet, 162a-electromagnet coil, 171, 172-wiring, 180-variable power supply, 821-recess, 822-through hole, 871-opening, Ma-film forming material, Mb-film forming material particles, P-plasma beam (plasma), R-channel, R1, R2, R3, R4-resistors, SW1, SW2-short-circuit switches. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the plasma gun, film forming device, and negative ion generating device according to the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are marked with the same symbols, and repeated descriptions are appropriately omitted. In addition, for ease of understanding, a portion of the drawings is sometimes simplified or enlarged, and the dimensional ratios are not limited to the dimensional ratios recorded in the drawings.

[0026] Figure 11 is a side sectional view showing a film forming apparatus according to the present embodiment. The film forming apparatus 1 according to the present embodiment is an ion plating apparatus used in an ion plating method. First, an exemplary film forming apparatus 1 to which the plasma gun according to the present embodiment can be applied is described. Figure 1 As shown, the XYZ coordinate system is used for explanation. The X-axis direction is the direction in which the film-forming object to be formed by the film-forming device 1 is opposite to the furnace mechanism 2 described later. The Y-axis direction is the conveying direction in which the film-forming object is conveyed. The Z-axis direction is a direction orthogonal to both the X-axis direction and the Y-axis direction.

[0027] The film forming device 1 includes a furnace mechanism 2, a conveying mechanism 3, a ring furnace 6, a plasma gun 7, a pressure regulating device 8, and a chamber 10. The chamber 10 includes: a conveying section 10a for conveying a film-forming object 11 on which a film of a film-forming material Ma is formed; a film-forming section 10b for diffusing the film-forming material Ma; and a plasma port 10c for collecting a plasma beam P irradiated from a plasma gun 7 into the chamber 10. The conveying section 10a is set along a predetermined conveying direction (the direction of arrow A in the figure, the positive direction of the Y axis). The conveying section 10a is made of a conductive material. The conveying section 10a is connected to the ground potential.

[0028] The conveying mechanism 3 conveys the object to be filmed 11 in a conveying direction A by holding the object to be filmed 11 in a state opposite to the film-forming material Ma. The conveying mechanism 3 is composed of a plurality of conveying rollers 15 provided inside the conveying portion 10a. The conveying rollers 15 are arranged, for example, at equal intervals along the conveying direction A, and convey the object to be filmed in the conveying direction A while supporting the object to be filmed holding portion 16. In addition, the object to be filmed 11 is a plate-shaped member such as a glass substrate or a plastic substrate.

[0029] The plasma gun 7 generates a plasma beam P inside the chamber 10. The plasma gun 7 is a pressure gradient type. The plasma gun 7 is connected to the film forming part 10b via a plasma port 10c provided on the side wall of the film forming part 10b. The plasma beam P generated in the plasma gun 7 is emitted from the plasma port 10c to the inside of the film forming part 10b. The emission direction of the plasma beam P is controlled by a steering coil 12 provided on the plasma port 10c. In addition, the plasma gun 7 will be described in detail later.

[0030] The pressure regulating device 8 is connected to the chamber 10 and regulates the pressure inside the chamber 10. The pressure regulating device 8 includes a decompression unit such as a turbomolecular pump or a cryopump and a pressure measuring unit for measuring the pressure inside the chamber 10, for example.

[0031] The hearth mechanism 2 is a mechanism for holding the film-forming material Ma. The hearth mechanism 2 is provided inside the film-forming section 10b of the chamber 10, and is arranged on the negative side of the X-axis when viewed from the conveying mechanism 3. The hearth mechanism 2 has a main hearth 21, which is a main anode that guides the plasma beam P emitted from the plasma gun 7 to the film-forming material Ma, or a main anode that guides the plasma beam P emitted from the plasma gun 7. The main hearth 21 is filled with the film-forming material Ma. Since the main hearth 21 maintains a positive potential relative to the ground potential of the chamber 10, it attracts the plasma beam P of the negative potential. In addition, the main hearth 21 is connected to a main power supply (not shown).

[0032] The annular hearth 6 is an auxiliary anode having an electromagnet for guiding the plasma beam P. The annular hearth 6 is arranged around the main hearth 21 that holds the film-forming material Ma. The annular hearth 6 has a coil 6a and a permanent magnet 6b. The annular hearth 6 controls the direction of the plasma beam P incident on the film-forming material Ma or the direction of the plasma beam P incident on the main hearth 21 according to the magnitude of the current flowing through the coil 6a.

[0033] As the film-forming material Ma, conductive materials such as ITO and ZnO, or insulating materials such as SiON are exemplified. When the film-forming material Ma is composed of an insulating material, when the plasma beam P is irradiated to the main furnace 21, the main furnace 21 is heated by the current from the plasma beam P. The front end portion of the film-forming material Ma heated by the main furnace 21 evaporates (gasifies), and the film-forming material particles Mb ionized by the plasma beam P diffuse into the inside of the film-forming part 10b.

[0034] When the film-forming material Ma is made of a conductive material, if the plasma beam P is irradiated on the main furnace 21, the plasma beam P directly enters the film-forming material Ma. As a result, the front end portion of the film-forming material Ma is heated and evaporated (gasified), and the film-forming material particles Mb ionized by the plasma beam P move in the positive direction of the X axis of the film-forming section 10b and adhere to the surface of the film-forming object 11 inside the conveying section 10a.

[0035] In addition, the film-forming material Ma is a solid object formed into a cylindrical shape, and a plurality of film-forming materials Ma are filled into the furnace mechanism 2 at one time. Then, according to the consumption of the film-forming material Ma, the film-forming material Ma is sequentially extruded from the negative direction side of the X-axis of the furnace mechanism 2 so that the front end portion of the film-forming material Ma maintains a predetermined positional relationship with respect to the upper end of the main furnace 21.

[0036] Next, refer to Figure 2 The plasma gun 7 will be described. Figure 22 is an exemplary cross-sectional view of the plasma gun 7. The plasma gun 7 includes an intermediate electrode 70 including a first intermediate electrode 71 and a second intermediate electrode 72, and a cathode flange 90 to which a cathode tube 80 is fixed. A glass tube (insulating tube) 92 accommodating the cathode tube 80 is disposed between the intermediate electrode 70 and the cathode flange 90.

[0037] The hole R provided in the intermediate electrode 70 keeps the pressure of the glass tube 92 higher than that of the chamber 10. The pressure difference between the pressure of the glass tube 92 and the pressure of the chamber 10 suppresses the mixing of reaction gases such as oxygen into the interior of the glass tube 92. As a result, the influence of oxygen during discharge is eliminated, and long-term continuous use is achieved. In addition, the intermediate electrode 70 is connected to a main power supply (not shown).

[0038] The second intermediate electrode 72 is annular. The second intermediate electrode 72 is fixed to the chamber 10 via a sealing gasket 73. On the side of the second intermediate electrode 72 opposite to the chamber 10 (the cathode flange 90 side), an annular first intermediate electrode 71 is fixed in a concentric overlapping manner via a sealing gasket 73. An air-core coil 74 is built into the second intermediate electrode 72. A permanent magnet 75 is built into the first intermediate electrode 71 in such a manner that the magnetic pole axis is parallel to the center line of the cathode tube 80. A glass tube 92 is mounted on the cathode flange 90 side of the first intermediate electrode 71.

[0039] A cathode tube 80 is fixed at the center of the cathode flange 90. Figure 3 Provide explanation. Figure 3 : is a cross-sectional view of the cathode tube 80. The cathode tube 80 comprises: a central tubular auxiliary electrode 81; a tube seat 82, which supports the auxiliary electrode 81 in a state fixed to the cathode flange 90; an outer tube 83, which surrounds the auxiliary electrode 81 and protrudes from the outer circumference of the tube seat 82 in the axial direction (extension direction) of the auxiliary electrode 81; and an annular main cathode 84 (electrode), which is arranged inside the outer tube 83 in a manner surrounding the front end of the auxiliary electrode 81.

[0040] The auxiliary electrode 81 is fixed in a state of being inserted into the recess 821 of the stem 82. A through hole 822 is connected to the recess 821. When the auxiliary electrode 81 is fixed inside the recess 821, the inside of the auxiliary electrode 81 and the through hole 822 are connected to each other. The through hole 822 of the stem 82 is connected to the cathode flange 90 (see Figure 2 ) is connected to a through hole (not shown) in the auxiliary electrode 81 and becomes a supply flow path for supplying an inert gas for discharge such as argon (Ar) gas. Thus, the auxiliary electrode 81 functions as an inert gas supply pipe for supplying an inert gas. As an example, the auxiliary electrode 81 is made of tungsten (W).

[0041] The outer cylinder 83 is a tubular member arranged in a manner surrounding the auxiliary electrode 81. The outer cylinder 83 opens one end side of the front end side (the side opposite to the tube seat 82) of the auxiliary electrode 81. The main cathode 84 is composed of, for example, lanthanum hexaboride (Lab6). In this case, more electrons can be released at low energy. However, the material of the main cathode 84 can be a material other than lanthanum hexaboride (Lab6), and can also include a material other than lanthanum hexaboride (Lab6). The materials of the electrodes used in the cathode tube 80, such as the main cathode 84, will be described in detail later.

[0042] The cathode is composed of the auxiliary electrode 81 and the main cathode 84. The main cathode 84 is supported by the outer cylinder 83 by being sandwiched by, for example, a first annular support member 85 and a second support member 86 (gasket) fixed in a manner of contacting the inner wall of the outer cylinder 83. However, the method of supporting the main cathode 84 inside the outer cylinder 83 is not limited to the above example. In addition, the cathode composed of the main cathode 84 and the auxiliary electrode 81 is connected to a main power supply not shown in the figure.

[0043] A circular cover 87 is provided at the front end of the outer cylinder 83 (the end on the side opposite to the tube seat 82). The cover 87 has an opening 871. The diameter (inner diameter) of the opening 871 is smaller than the opening diameter of the outer cylinder 83 and larger than the inner diameter of the auxiliary electrode 81. The cover 87 is fixed to the outer cylinder 83 via a third support member 88 having an opening larger than the opening 871. In addition, there is no particular limitation on the fixing method of the cover 87. The main cathode 84 and the auxiliary electrode 81 are protected by the cover 87 and the outer cylinder 83.

[0044] In the plasma gun 7 including the cathode tube 80 configured as described above, the inert gas supplied from the gas tank (not shown) passes through the through hole 822 of the tube base 82 and the inside of the auxiliary electrode 81. Then, the inert gas is released from the front end of the auxiliary electrode 81 and supplied to the internal space of the glass tube 92. As a result, a pressure gradient is generated inside the plasma gun 7 in which the pressure on the cathode (main cathode 84 and auxiliary electrode 81) side becomes higher.

[0045] When a voltage is applied between the main furnace 21, which serves as an anode, and the main cathode 84, which serves as a cathode, and the auxiliary electrode 81, which serves as a cathode, by a main power supply (not shown), glow discharge occurs in the auxiliary electrode 81. The temperature of the tip portion of the auxiliary electrode 81 rises due to the glow discharge, and the main cathode 84 is heated by the heat to a high temperature. As a result, arc discharge (DC arc discharge) occurs in the auxiliary electrode 81 and the main cathode 84, and high-temperature electrons are emitted from the cathodes (auxiliary electrode 81 and main cathode 84) to generate plasma. The generated plasma passes through the hole R formed in the center of the first intermediate electrode 71 and the second intermediate electrode 72, and is emitted from the plasma port 10c to the inside of the chamber 10. The plasma emitted into the inside of the chamber 10 reaches the main furnace 21 as a plasma beam P while being guided by the steering coil 12 and the like in the inside of the chamber 10, and heats the film-forming material Ma contained in the main furnace 21. The evaporated metal particles are ionized in the plasma, and adhere to the film-forming object 11 to which a negative voltage is applied, and a film is formed on the film-forming object 11.

[0046] The outer tube 83, the first support member 85, the second support member 86, and the third support member 88 of the cathode tube 80 are made of, for example, molybdenum (Mo). On the other hand, the material of the cover 87 includes the same material as the material of the main cathode 84. As described above, since the material of the main cathode 84 is, for example, lanthanum hexaboride (Lab6), the material of the cover 87 includes lanthanum hexaboride (Lab6).

[0047] Figure 4 is a graph showing the relationship between the temperature of the material used as the electrode of the cathode tube 80 and the current density. Figure 5 is a table showing the properties of materials used as electrodes of the cathode tube 80. Figure 4 and Figure 5 As shown, the electrode of the cathode tube 80 may include at least one of lanthanum hexaboride (Lab6), W / Th (thorium dispersed tungsten), Nb (niobium), Ta (tantalum), Zr (zirconium), Mo (molybdenum), W (tungsten) and Re (rhenium). However, as the material of the electrode of the cathode tube 80, it is preferred that the work function φw is small, that is, a high current density can be obtained even at low temperatures. From this point of view, lanthanum hexaboride and thorium dispersed tungsten are preferred. However, compared with thorium dispersed tungsten, lanthanum hexaboride is more readily available and can be used in various operating environments, so it has the advantages of suppressing costs and good operability. Therefore, in this embodiment, lanthanum hexaboride is used as the material of the electrode (main cathode 84) of the cathode tube 80.

[0048] As described above, the material of the cover 87 includes the same material as the electrode material of the cathode tube 80. Thus, the cover 87 may include at least one of lanthanum hexaboride (Lab6), W / Th (thorium dispersed tungsten), Nb (niobium), Ta (tantalum), Zr (zirconium), Mo (molybdenum), W (tungsten) and Re (rhenium). Furthermore, as the material of the cover 87, lanthanum hexaboride and thorium dispersed tungsten are preferred, and lanthanum hexaboride is further preferred. In this case, the cover 87 can function in the same manner as the electrode (main cathode 84) of the cathode tube 80. In addition, the material of the outer cylinder 83, the first support member 85, the second support member 86 and the third support member 88 may be the same as the material of the cover 87.

[0049] Next, the effects of the plasma gun 7 according to this embodiment will be described. Figure 3 As shown, in the plasma gun 7, the main cathode 84 is arranged inside the outer cylinder 83 opened at one end, and the cover 87 with the opening 871 is installed at one end of the outer cylinder 83. The diameter of the opening 871 of the cover 87 is smaller than the opening diameter of the outer cylinder 83, and the material of the cover 87 includes the same material as the material of the main cathode 84. Therefore, even if the material of the cover 87 of the cathode tube 80 adheres to the main cathode 84, the amount of impurities adhering to the main cathode 84 can be reduced by the material of the cover 87 including the material of the main cathode 84.

[0050] Thus, it is possible to suppress the mixing of impurities into the film (film-forming material Ma) and the generation of defects in the product (film-forming object 11). Furthermore, even if the material of the cover 87 containing the material of the main cathode 84 is attached to the main cathode 84, the discharge is not likely to become unstable. In addition, since the material of the cover 87 contains the material of the cathode 84, the cover 87 can function as an electrode. Therefore, the surface area of ​​the portion that functions as an electrode can be increased, so the discharge power can be increased. Thus, a larger current than before can be passed.

[0051] As described above, the cover 87 may be made of the same material as the main cathode 84. In this case, since the cover 87 is made of the electrode material, it is possible to stabilize the discharge while preventing impurities from adhering to the main cathode 84. In addition, the discharge power can be increased so that a larger current can flow.

[0052] As described above, the cover 87 may be made of lanthanum hexaboride (Lab6). In this case, since the cover 87 is made of Lab6, more electrons can be released. Therefore, since the cover 87 can be used as a hot electron generation source, a larger current can flow.

[0053] The film forming apparatus 1 has been described above. However, the structure of the film forming apparatus is not limited to the above examples. A negative ion generating device for irradiating negative ions to the semiconductor film may be incorporated into the film forming apparatus. Figure 6 The film forming apparatus 101 in which the negative ion generating apparatus 124 is incorporated will be described.

[0054] The negative ions used in the film forming device 101 are substances with positive electron affinity, and oxygen negative ions can be used. As negative ions, atoms such as H, C, O, F, Si, S, Cl, Br, or I can be used, and molecules such as O2, Cl2, Br2, I2, CH, OH, CN, HCl, HBr, NH2, N2O, NO2, CCl4, or SF6 can be used. There is no particular limitation on the degree of negative ions irradiated to the semiconductor film by the negative ion generating device 124, but for example, 1×10 19 cm -3 The irradiation amount of negative ions may be an amount that allows surface precipitation or grain boundary precipitation. In this case, the irradiated negative ions diffuse into the semiconductor film and act as an effective dopant.

[0055] The film forming device 101 is an ion plating device used in the so-called ion plating method. Figure 6 : The XYZ coordinate system is shown in . The Y-axis direction is the direction in which the non-single crystal substrate 103 described later is transported. The X-axis direction is the direction in which the non-single crystal substrate 103 and the furnace mechanism described later are opposed. The Z-axis direction is a direction orthogonal to the Y-axis direction and the X-axis direction.

[0056] The film forming apparatus 101 is a so-called vertical film forming apparatus, and the non-single crystal substrate 103 is arranged in a horizontal direction ( Figure 6 The non-single crystal substrate 103 is placed in a vacuum chamber 110 and transported in a state where the non-single crystal substrate 103 is upright or tilted from the upright state (in the X-axis direction). The film forming apparatus 101 includes a vacuum chamber 110, a transport mechanism 113, a film forming unit 114, a negative ion generating device 124, and a magnetic field generating coil 130.

[0057] The vacuum chamber 110 accommodates the non-single crystal substrate 103 and performs film forming. The vacuum chamber 110 has: a conveying chamber 110a for conveying the non-single crystal substrate 103 on which a film of a film forming material Ma is formed; a film forming chamber 110b for diffusing the film forming material Ma; and a plasma port 110c for receiving the plasma P irradiated in a beam form from the plasma source 107 into the vacuum chamber 110.

[0058] The film forming chamber 110b is, for example, a negative ion generating chamber, which attaches electrons to the negative ion raw material by supplying plasma P to the raw material. The film forming chamber 110b has a pair of side walls along the conveying direction (arrow A) as a wall portion 110w, a pair of side walls 110h and 110i along the direction (Z-axis direction) intersecting the conveying direction (arrow A), and a bottom wall 110j arranged to intersect the X-axis direction. The conveying mechanism 113 conveys the non-single crystal substrate holding member 116 that holds the non-single crystal substrate 103 in a state opposite to the film forming material Ma in the conveying direction (arrow A). For example, the non-single crystal substrate holding member 116 is a frame that holds the outer periphery of the non-single crystal substrate 103. The conveying mechanism 113 is composed of a plurality of conveying rollers 115 provided in the conveying chamber 110a. The conveying rollers 115 are arranged at equal intervals along the conveying direction (arrow A), and convey the non-single crystal substrate holding member 116 in the conveying direction (arrow A) while supporting it. In addition, as the non-single-crystal substrate 103 , for example, a plate-shaped member such as a non-single-crystal substrate or a plastic substrate is used.

[0059] Next, the structure of the film forming unit 114 is described in detail. The film forming unit 114 attaches particles of the film forming material Ma to the non-single crystal substrate 103 by ion plating. The film forming unit 114 includes a plasma source 107, a steering coil 125, a furnace mechanism 122, and a ring furnace 106. The plasma source 107 is, for example, a pressure gradient type plasma gun, and its main body is connected to the film forming chamber 110b via a plasma port 110c provided on the side wall of the film forming chamber 110b. The plasma source 107 generates plasma P in the vacuum chamber 110. The plasma P generated in the plasma source 107 is ejected from the plasma port 110c into the film forming chamber 110b in a beam shape.

[0060] One end of the plasma source 107 is closed by an electrode 160. As with the plasma gun 7, Figure 3 As shown in the example, the plasma source 107 is provided with an electrode 160 inside an outer cylinder 83 opened at one end, and a cover 87 with an opening 871 is installed at one end of the outer cylinder 83. The diameter of the opening 871 of the cover 87 is smaller than the opening diameter of the outer cylinder 83, and the material of the cover 87 includes the same material as the material of the electrode 160. The cover 87 is made of the same material as the material of the electrode 160, for example.

[0061] like Figure 6 As shown, a first intermediate electrode (grid) 161 and a second intermediate electrode (grid) 162 are concentrically arranged between the electrode 160 and the plasma port 110c. An annular permanent magnet 161a for converging the plasma P is built into the first intermediate electrode 161. An electromagnetic coil 162a for converging the plasma P is also built into the second intermediate electrode 162.

[0062] The steering coil 125 is disposed around the plasma port 110c to which the plasma source 107 is installed. The steering coil 125 guides the plasma P into the film forming chamber 110b. The steering coil 125 is excited by a steering coil power supply (not shown). The furnace mechanism 122 holds the film forming material Ma. The furnace mechanism 122 is disposed in the film forming chamber 110b of the vacuum chamber 110, and is arranged in the negative direction of the X-axis direction when viewed from the conveying mechanism 113. The furnace mechanism 122 has a main furnace 117, which is a main anode that guides the plasma P emitted from the plasma source 107 to the film forming material Ma, or a main anode to which the plasma P emitted from the plasma source 107 is guided.

[0063] The main furnace 117 has a cylindrical filling portion 117a extending in the positive direction of the X-axis direction and filled with a film-forming material Ma, and a flange portion 117b protruding from the filling portion 117a. In the filling portion 117a of the main furnace 117 into which the plasma P is incident, a through hole 117c for filling the film-forming material Ma is formed. Moreover, the front end portion of the film-forming material Ma is exposed to the film-forming chamber 110b at one end of the through hole 117c. In the case where the film-forming material Ma is composed of an insulating material, if the plasma P is irradiated to the main furnace 117, the main furnace 117 is heated by the current from the plasma P, the front end portion of the film-forming material Ma evaporates or sublimates, and the film-forming material particles (evaporated particles) Mb ionized by the plasma P diffuse into the film-forming chamber 110b. Furthermore, when the film-forming material Ma is composed of a conductive material, if the plasma P is irradiated on the main furnace 117, the plasma P directly enters the film-forming material Ma, the front end portion of the film-forming material Ma is heated and evaporated or sublimated, and the film-forming material particles Mb ionized by the plasma P diffuse into the film-forming chamber 110b. The film-forming material particles Mb diffused into the film-forming chamber 110b move in the positive direction of the X-axis of the film-forming chamber 110b, and adhere to the surface of the non-single crystal substrate 103 in the conveying chamber 110a.

[0064] The annular furnace 106 is an auxiliary anode having an electromagnet for guiding plasma P. The annular furnace 106 is arranged around the filling part 117a of the main furnace 117 that holds the film-forming material Ma. The annular furnace 106 has an annular coil 109, an annular permanent magnet part 120 and an annular container 112, and the coil 109 and the permanent magnet part 120 are accommodated in the container 112. The annular furnace 106 controls the direction of the plasma P incident on the film-forming material Ma or the direction of the plasma P incident on the main furnace 117 according to the magnitude of the current flowing through the coil 109.

[0065] Next, the structure of the negative ion generating device 124 is described in detail. The negative ion generating device 124 includes a plasma source 107, a raw material gas supply unit 140, a control unit 150, and a circuit unit 134. The plasma source 107 intermittently generates plasma P in the film forming chamber 110b. Specifically, the plasma source 107 is controlled by the control unit 150 to intermittently generate plasma P in the film forming chamber 110b.

[0066] The control unit 150 controls, for example, the generation state of the plasma P in the vacuum chamber 110. The control unit 150 reduces the electron temperature of the plasma P in the vacuum chamber 110. The raw gas supply unit 140 is arranged outside the vacuum chamber 110. The raw gas supply unit 140 supplies raw gas of oxygen anions, i.e., oxygen, into the vacuum chamber 110 through a gas supply port 141 provided on a side wall (e.g., side wall 110h) of the film forming chamber 110b. If, for example, the raw gas supply unit 140 switches from the film forming process mode to the oxygen anion generation mode, the supply of oxygen starts. Furthermore, the raw gas supply unit 140 can continuously supply oxygen in both the film forming process mode and the oxygen anion generation mode.

[0067] The position of the gas supply port 141 may be near the boundary between the film forming chamber 110b and the transport chamber 110a. In this case, since the oxygen gas from the raw material gas supply unit 140 can be supplied near the boundary between the film forming chamber 110b and the transport chamber 110a, oxygen anions described later are generated near the boundary. Therefore, the generated oxygen anions can be appropriately attached to the non-single crystal substrate 103 in the transport chamber 110a.

[0068] The control unit 150 is arranged outside the vacuum chamber 110. The control unit 150 switches the switching unit of the circuit unit 134. The switching of the switching unit by the control unit 150 will be described in detail below together with the description of the circuit unit 134. The circuit unit 134 includes a variable power supply 180, a first wiring 171, a second wiring 172, resistors R1 to R4, and short-circuit switches SW1 and SW2. The variable power supply 180 applies a negative voltage to the electrode 160 of the plasma source 107 and a positive voltage to the main furnace 117 of the furnace mechanism 122 via the vacuum chamber 110 at the ground potential. Thus, the variable power supply 180 generates a potential difference between the electrode 160 of the plasma source 107 and the main furnace 117 of the furnace mechanism 122.

[0069] The first wiring 171 electrically connects the electrode 160 of the plasma source 107 to the negative potential side of the variable power supply 180. The second wiring 172 electrically connects the main furnace 117 (anode) of the furnace mechanism 122 to the positive potential side of the variable power supply 180. One end of the resistor R1 is electrically connected to the first intermediate electrode 161 of the plasma source 107, and the other end thereof is electrically connected to the variable power supply 180 via the second wiring 172. That is, the resistor R1 is connected in series between the first intermediate electrode 161 and the variable power supply 180.

[0070] One end of the resistor R2 is electrically connected to the second intermediate electrode 162 of the plasma source 107, and the other end thereof is electrically connected to the variable power supply 180 via the second wiring 172. That is, the resistor R2 is connected in series between the second intermediate electrode 162 and the variable power supply 180. One end of the resistor R3 is electrically connected to the wall portion 110w of the film forming chamber 110b, and the other end thereof is electrically connected to the variable power supply 180 via the second wiring 172. That is, the resistor R3 is connected in series between the wall portion 110w of the film forming chamber 110b and the variable power supply 180.

[0071] One end of the resistor R4 is electrically connected to the ring hearth 106, and the other end thereof is electrically connected to the variable power supply 180 via the second wiring 172. That is, the resistor R4 is connected in series between the ring hearth 106 and the variable power supply 180. The short-circuit switches SW1 and SW2 are switching parts that are switched to the ON / OFF state by receiving command signals from the aforementioned control part 150, respectively. The ease of flow of current to the electrode (the second intermediate electrode 162) is switched by the switching part.

[0072] The short-circuit switch SW1 is connected in parallel with the resistor R2. The short-circuit switch SW1 is switched to an ON / OFF state by the control unit 150 according to whether it is the film forming process mode or the oxygen negative ion mode. The short-circuit switch SW1 is set to an OFF state in the film forming process mode. Thus, in the film forming process mode, the second intermediate electrode 162 and the variable power supply 180 are electrically connected to each other via the resistor R2, so that it is difficult for current to flow between the second intermediate electrode 162 and the variable power supply 180. As a result, the plasma P from the plasma source 107 is ejected into the vacuum chamber 110 and incident on the film forming material Ma.

[0073] On the other hand, the short-circuit switch SW1 is switched between ON and OFF at predetermined intervals by the control unit 150 in the oxygen negative ion generation mode to intermittently generate plasma P from the plasma source 107 in the vacuum chamber 110. When the short-circuit switch SW1 is switched to the ON state, the electrical connection between the second intermediate electrode 162 and the variable power supply 180 is short-circuited, so that current flows between the second intermediate electrode 162 and the variable power supply 180. That is, a short-circuit current flows in the plasma source 107. As a result, the plasma P from the plasma source 107 is not ejected into the vacuum chamber 110.

[0074] When the short-circuit switch SW1 is switched to the OFF state, since the second intermediate electrode 162 and the variable power supply 180 are electrically connected to each other via the resistor R2, it is difficult for current to flow between the second intermediate electrode 162 and the variable power supply 180. As a result, the plasma P from the plasma source 107 is ejected into the vacuum chamber 110. In this way, the ON / OFF state of the short-circuit switch SW1 is switched by the control unit 150 at a predetermined interval, so that the plasma P from the plasma source 107 is intermittently generated in the vacuum chamber 110. That is, the short-circuit switch SW1 is a switching unit that switches the supply and cutoff of the plasma P into the vacuum chamber 110.

[0075] The short-circuit switch SW2 is connected in parallel with the resistor R4. The short-circuit switch SW2 is switched to an ON / OFF state by the control unit 150, for example, depending on whether the state before the non-single crystal substrate 103 is transported before the film forming process mode, that is, the standby mode, or the film forming process mode. The short-circuit switch SW2 is set to an ON state in the standby mode. Thus, since the electrical connection between the ring furnace 106 and the variable power supply 180 is short-circuited, it is easier for current to flow in the ring furnace 106 than in the main furnace 117, and unnecessary waste of the film forming material Ma can be prevented.

[0076] On the other hand, the short-circuit switch SW2 is set to the OFF state in the film forming processing mode. Therefore, since the ring furnace 106 and the variable power supply 180 are electrically connected via the resistor R4, it is easier for current to flow through the main furnace 117 than the ring furnace 106, and the emission direction of the plasma P can be appropriately directed toward the film forming material Ma. In addition, the short-circuit switch SW2 can be set to either the ON state or the OFF state in the oxygen negative ion generation mode.

[0077] The magnetic field generating coil 130 suppresses the flow of electrons in the film forming chamber 110b into the conveying chamber 110a during the generation of negative ions in the negative ion generating chamber, i.e., the film forming chamber 110b. The magnetic field generating coil 130 is disposed between the film forming chamber 110b and the conveying chamber 110a in the vacuum chamber 110. The magnetic field generating coil 130 is disposed, for example, between the furnace mechanism 122 and the conveying mechanism 113. More specifically, the magnetic field generating coil 130 is located between the end of the film forming chamber 110b on the conveying chamber 110a side and the end of the conveying chamber 110a on the film forming chamber 110b side. The magnetic field generating coil 130 has a pair of coils 130a and 130b facing each other. The respective coils 130a and 130b face each other, for example, in a direction intersecting with the direction from the film forming chamber 110b toward the conveying chamber 110a (the direction from the furnace mechanism 122 toward the conveying mechanism 113). The magnetic field generating coil 130 forms, for example, a sealing magnetic field in the vacuum chamber 110 , the sealing magnetic field having magnetic force lines extending in a direction intersecting a direction from the film forming chamber 110 b toward the transfer chamber 110 a .

[0078] The magnetic field generating coil 130 is not excited in the film forming process mode, but is excited by a power supply (not shown) in the oxygen negative ion generating mode. Here, the film forming process mode is a mode in which a film forming process is performed on the non-single crystal substrate 103 in the vacuum chamber 110. The oxygen negative ion generating mode is a mode in which oxygen negative ions are generated in the vacuum chamber 110 to adhere to the surface of the film formed on the non-single crystal substrate 103.

[0079] As described above, in the film forming device 101 equipped with the negative ion generating device 124, Figure 3 As illustrated, in the plasma source 107, the electrode 160 is provided inside the outer cylinder 83 opened at one end, and the cover 87 with the opening 871 is installed at one end of the outer cylinder 83. The diameter of the opening 871 of the cover 87 is smaller than the opening diameter of the outer cylinder 83, and the material of the cover 87 includes the same material as the material of the electrode 160. Therefore, even if the material of the cover 87 adheres to the electrode 160, the amount of impurities adhering to the electrode 160 can be reduced by the material of the cover 87 including the material of the electrode 160.

[0080] As a specific example, when the electrode 160 is made of LaB6 and the cover 87 is made of tungsten, tungsten adheres to the electrode 160 during use of the negative ion generating device 124, and the attached tungsten does not peel off, so it can be assumed that the re-discharge after the device is stopped is unstable. In contrast, in this embodiment, since the amount of tungsten attached to the electrode 160 can be reduced by including the material of the electrode 160 in the material of the cover 87, it helps to stabilize the electrode 160. Therefore, the film forming device 101 equipped with the negative ion generating device 124 can obtain the same effect as the aforementioned film forming device 1.

[0081] The above describes the embodiments of the plasma gun, film-forming device, and negative ion generating device involved in the present invention. However, the present invention is not limited to the aforementioned embodiments, and can be modified without changing the main purpose described in the various technical schemes. The structure, function, shape, size, quantity, material, and configuration of each part of the plasma gun, film-forming device, and negative ion generating device involved in the present invention can be appropriately changed without departing from the above-mentioned main purpose. That is, the structure of the aforementioned film-forming device 1, plasma gun 7, cathode tube 80, and negative ion generating device 124 is only an example, and the shape and structure of the film-forming device, plasma gun, cathode tube, and negative ion generating device can be appropriately changed.

Claims

1. A plasma gun, comprising a cathode tube, wherein the cathode tube has: The outer tube is open at one end; A main cathode is disposed inside the outer cylinder; and a cover body, mounted on the one end side of the outer tube and having an opening smaller than the cross-sectional size of the one end of the outer tube, The material of the cover body includes the same material as that of the main cathode.

2. The plasma gun according to claim 1, wherein: The cover is made of the same material as that of the main cathode.

3. The plasma gun according to claim 1 or 2, wherein: The cover is made of lanthanum hexaboride (LaB6).

4. A film forming device, comprising a plasma gun having a cathode tube, wherein the cathode tube comprises: An outer cylinder, one end of which is open; a main cathode, which is arranged inside the outer cylinder; and a cover body, which is mounted on the one end side of the outer tube and has an opening smaller than the cross-sectional size of the one end of the outer tube, The material of the cover body includes the same material as that of the main cathode.

5. A negative ion generating device for irradiating an object with negative ions, The negative ion generating device includes a plasma source for supplying plasma into a vacuum chamber. The plasma source has: The outer tube is open at one end; A main cathode is disposed inside the outer cylinder; and a cover body, mounted on the one end side of the outer tube and having an opening smaller than the cross-sectional size of the one end of the outer tube, The material of the cover body includes the same material as that of the main cathode.

6. The negative ion generating device according to claim 5, The plasma source includes a control unit configured to control the plasma source so that the plasma source intermittently generates plasma.

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