Patent Publication Number: US-2012037504-A1

Title: Multiply Divided Anode Wall Type Plasma Generating Apparatus and Plasma Processing Apparatus

Description:
FIELD OF THE INVENTION 
     The present invention concerns a plasma generation apparatus in which the supply source of the plasma constituent is made to be the cathode, a cylinder-like anode is set up at the front or perimeter of said cathode, and plasma is generated from the surface of said cathode by doing a vacuum arc discharge between said cathode and said anode under a vacuum environment, and a plasma processing apparatus that does plasma treatment such as film formation by anode by means of the generated plasma from said plasma generation apparatus. To be specific, the present invention concerns a multiply divided anode wall type plasma generation apparatus, and a plasma processing apparatus that uses the former. 
     BACKGROUND ART 
     Normally, it is known that by forming a thin film or injecting ions in plasma onto the surface of a solid material, the solid surface characteristics are improved. A film formed using plasma including metal ions and nonmetal ions strengthens the abrasion and corrosion resistances of a solid surface, and it is useful as a protective film, an optical thin film, and a transparent electroconductive film among others. In particular, as for carbon films using carbon plasma, the utility value is high as diamond like carbon films (so-called DLC films) comprising amorphous mixed crystals of diamond and graphite structures. 
     As a method for generating plasma including metal ions and nonmetal ions, there is a vacuum arc plasma method. Vacuum are plasma is formed by an arc discharge occurring between a cathode and an anode. The cathode material evaporates from an existing cathode spot of the cathode surface, and it is plasma formed by this vaporized cathode material. Also, when a reactive gas is introduced as the environmental gas, the reactive gas is ionized simultaneously. An inert gas (so-called noble gas) may be introduced together with said reactive gas, and said inert gas can also be introduced instead of said reactive gas. By means of such plasma, a surface treatment can be done by a thin film formation or an ion injection onto a solid surface. 
     Normally, in a vacuum arc discharge, at the same time as vacuum arc plasma constituent particles such as cathode material ions, electrons, and cathode material neutral atom groups (atoms and molecules) are ejected by a cathode spot, cathode material particles named droplets of size ranging from less than submicron to several hundred microns (0.01-1000 μm) are also ejected. When these droplets adhere to the surface of an object to be treated, the uniformity of a film formed on the surface of the object to be treated surface is lost, a defective thin film is produced, and the surface treatment result of the film formation is affected. 
     A plasma arc machining apparatus having a droplet collecting portion is disclosed in Japanese Patent Laid-Open No. 2002-8893 bulletin (Patent Document 1).  FIG. 21  is an outlined schematic diagram of a conventional plasma processing apparatus concerning Patent Document 1. At plasma generating portion  200 , an electric spark is caused between cathode  201  and trigger electrode  202 , and plasma  204  is produced by generating a vacuum arc between cathode  201  and anode  203 . Power supply  205  for generating an electric spark and a vacuum arc discharge is connected to plasma generating portion  200 , and plasma stabilizing magnetic field generators  206 ,  207  for stabilizing plasma  204  are positioned. Plasma  204  is guided to plasma processing portion  208  from plasma generating portion  200 , and object to be treated  209  placed in plasma processing portion  208  is surface-treated by plasma  204 . Also, a reactive gas is introduced as necessary by gas introduction system  210  connected to plasma processing portion  208 , and reactant gases and the plasma stream are exhausted by gas exhaust system  211 . 
     Plasma  204  ejected from plasma generating portion  200  is bent to a T-shape toward a direction away from plasma generating portion  200  by the magnetic field, and is flowed into plasma processing portion  208 . At the position facing plasma generating portion  200 , droplet collecting portion  212  is positioned, where cathode material particles (droplets)  213  generated as a byproduct at cathode at the time of generation of plasma  204  are collected. Therefore, droplets  213  not under an influence of the magnetic field advances to droplet collecting portion  212  and are collected, thereby preventing an intrusion of droplets  213  into plasma processing portion  208 . 
     [Patent Document 1] Japanese Patent Laid-Open No. 2002-8893 bulletin 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     The conventional plasma crafting apparatus uses anode  203  comprising a cylinder-shaped electrode cylindrical body  214  extending toward the front side of cathode  201 . 
       FIG. 22  shows the inner wall surface of a conventional electrode cylindrical body  214 . When anode  203  is made to be the whole of the tube inside wall, because a vacuum arc becomes hard to be generated between it and cathode  201 , many ring-like protruding portions  216  are set up by engraving multiple circular grooves  215  in the inner wall of electrode cylindrical body  214 , so that a vacuum arc is generated smoothly between it and cathode  201 . 
     When the plasma generated between cathode  201  and electrode cylindrical body  214  of anode  203  is released further forward than cathode  201  and diffused, diffusing material  218 , mainly carbon (C) particles among the vacuum arc plasma constituent particles, recrystallizes on the inner wall of electrode cylindrical body  214  mainly, to adhere and deposit. In particular, when the recrystallization proceeds on the surface of a protruding portion  216 , the deposited matter detaches in a flake-like configuration, and falls toward the cathode  201  side. However, because protruding portions  216  have a ring-like configuration, a problem occurs as shown in  FIG. 22 , in that when carbon flake  220  deposited in an elongated shape detaches from circular arc part  219  of a protruding portion  216  and falls toward the side of cathode  201 , one end of carbon flake  220  is caught at upper side  217  of cathode  201  in a bridging manner, the other end comes in contact with anode  203 , and cathode  201  and anode  203  are short-circuited. 
     The object of the present invention, in the view of the above problem, is to provide a multiply divided anode wall type plasma generation apparatus that can prevent a short-circuit between cathode and anode by a detached deposited matter that had adhered and deposited on the anode inner wall from the diffusion plasma, and a plasma processing apparatus that uses this. 
     Means to Solve the Problems 
     The present inventors, as a result of having studied intensively to solve the short-circuit problem that occurs through the detachment phenomenon of large carbon flakes from ringed protruding portions, have succeeded in a size reduction of carbon flakes by a multiple division of the anode inner wall, and have thus solved the problem. 
     The first form of the present invention is, in a plasma generation apparatus in which a supply source of a plasma constituent is made to be a cathode, a cylinder-shaped anode is installed at a front direction or a periphery of said cathode, a vacuum arc discharge is done between said cathode and said anode under a vacuum environment, and plasma is generated from said cathode surface, a plasma generation apparatus, characterized in that a large number of recesses and protrusions is built on a cylinder inner wall that comprises said anode, so that when a part of said plasma ejected from said cathode to a direction of said anode adheres and deposits to said recesses and protrusions, said deposited matter detaches from said anode as a minute fragment. 
     The second form of the present invention is the plasma generation apparatus of the first form, wherein the longest length of a protruding portion of said recesses and protrusions is made shorter than the width of a gap between said cylinder inner wall and an outer circumference of said cathode. 
     The third form of the present invention is the plasma generation apparatus of the first or second form, wherein a large number of said recesses and protrusions is formed from any one of lattice-like, diagonally crossing, and island-like patterns. 
     The fourth form of the present invention is the plasma generation apparatus of the first, second, or third form, wherein within said cylinder inner wall comprising said anode, the area near said cathode is made to be a formation area of said pattern for said recesses and protrusions, and an annular groove pattern, in which a multiple annular grooves are engraved in a front direction of said cathode, is formed on a remaining area of said cylinder inner wall. 
     The fifth form of the present invention is the plasma generation apparatus of any one of the first to fourth forms, wherein an annular recess position is formed at a periphery of said cathode, so that said minute piece detached from said anode is retained and collected in said annular recess position. 
     The sixth form of the present invention is the plasma generation apparatus of any one of the first to fifth forms, wherein a retention portion for said minute piece is installed beneath said cathode, and at the same time, an exposing portion that communicates with said retention portion is formed at a periphery of said cathode, so that said minute piece detached from said anode is retained and collected in said retention portion through said exposing portion. 
     The seventh form of the present invention is a plasma processing apparatus, characterized in that it includes the plasma generation apparatus concerning any one of the first to sixth forms, a plasma transport tube that transports said plasma generated by said plasma generating apparatus, and a plasma processing portion that processes an object to be treated by said plasma supplied from said plasma transport tube. 
     The eighth form of the present invention is the plasma processing apparatus of the seventh form, wherein a starting end side insulator is interposed between a plasma outlet in a cylindrical body of said anode and said plasma transport tube, a finishing end side insulator is interposed between said plasma transport tube and said plasma processing portion, and said plasma generating portion, said plasma transport tube, and said plasma processing portion are mutually separated electrically so that an electric influence from said plasma generating portion and said plasma processing portion on said plasma transport tube is blocked. 
     The ninth form of the present invention is the plasma processing apparatus of the seventh or eighth form, wherein said plasma transport tube comprises a plasma straightly advancing tube connected to said plasma generating portion, a first plasma advancing tube connected in a bent manner to said plasma straightly advancing tube, a second plasma advancing tube diagonally arranged and connected at a finishing end of said first plasma advancing tube in a bent manner with predetermined bending angle with respect to a tube axis of said first plasma advancing tube, a third plasma advancing tube connected in a bent manner to a finishing end of said second plasma advancing tube so that said plasma is exhausted from a plasma outlet, and total length L for said plasma to arrive from said target surface to said object to be treated is set to satisfy 900 mm≦L≦1350 mm. 
     The tenth form of the present invention is the plasma processing apparatus of the seventh, eighth, or ninth form, wherein said second plasma advancing tube is placed geometrically at a position off a straight line of sight from a plasma outlet of said third plasma advancing tube to a plasma outlet side of said first plasma advancing tube. 
     The eleventh form of the present invention is the plasma processing apparatus of the ninth or tenth form, wherein θ≧θ 0  is satisfied when an angle of elevation from a tube cross section top end of the plasma entrance port side of said third plasma advancing tube to a tube cross section bottom end of the plasma outlet side of said first plasma advancing tube is defined as θ, and an angle of elevation from a tube cross section bottom end of the plasma outlet side of said third plasma advancing tube to a tube cross section top end of the plasma outlet side of said second plasma advancing tube is defined as θ 0 . 
     The twelfth form of the present invention is the plasma processing apparatus of any one of the eighth to eleventh forms, wherein a magnetic field generating means for plasma transportation that generates a magnetic field for plasma transportation is set up in each of said plasma straightly advancing tube, said first plasma advancing tube, said second plasma advancing tube, and said third plasma advancing tube, a deflection magnetic field generating means for deflecting said magnetic field for plasma transportation is attached in said first plasma advancing tube and/or said second plasma advancing tube, and a plasma stream is deflected toward a tube center side by a deflection magnetic field generated by said deflection magnetic field generating means. 
     Effects of the Invention 
     According to the first form of the present invention, a large number of said recesses and protrusions are arranged in the cylinder inner wall forming said anode so that it is multiply divided, and by the deposited matter separation effect of the large number of said recesses and protrusions, even if the diffusion plasma adheres and deposits to said anode, a large or elongated deposited matter do not form, and said deposited matter detaches as a minute piece from said anode. Because of this, said deposited matter do not bridge across said cathode and said anode upon detaching, a generation of short circuit between two electrodes can be prevented, and it contributes to a stable operation and an improvement of the operation efficiency of the plasma generation apparatus. 
     The placement of the anode in the present invention can be carried out so that it is located forward of the cathode, or in a placement form in which it surrounds a part or the whole of the cathode. Also, the cylindrical body structure of the anode is not limited to a cylindrical form with a uniform inside diameter, but the present invention can be applied with a frusto-conical internal wall structure. 
     The deposited matter as a carbon flake grows in a way associated with the size of the protruding portion surface of said recesses and protrusions. Therefore, according to the second form of the present invention, because the longest length of the protruding portions of said recesses and protrusions is made shorter than the width of the gap between said cylinder inner wall and the outer circumference of said cathode, a deposited matter larger than said gap does not detach, and a generation of a short circuit between the cathode and the anode can be prevented without causing a bridge formation by said deposited matter. 
     According to the third form of the present invention, because the large number of said recesses and protrusions is formed from any one of lattice-like, diagonally crossing, and island-like patterns, a multiple division of the cylinder inner wall forming said anode can be realized, the size of said deposited matter is reduced by the deposited matter separation effect of each pattern, and a generation of short circuit between the cathode and the anode can be prevented without causing a bridge formation by said deposited matter. 
     As for the quantity of deposition by diffusion plasma, it shows a tendency to increase in the periphery of said cathode that is the source of supply of the plasma constituent. Therefore, according to the fourth form of the present invention, by paying attention to this deposition tendency, a size reduction of the deposited matter is realized, by making the area near said cathode, within said cylinder inner wall comprising said anode, to be a formation area of said pattern for said recesses and protrusions. Also, by forming an annular groove pattern, in which a multiple annular grooves are engraved in the front direction of said cathode, on the remaining area of said cylinder inner wall, an area of the anode protruding portions formed by said annular groove pattern is obtained, inducing the generation of a vacuum arc with high efficiency. Because of these, a generation of short circuit between the cathode and the anode is prevented, and at the same time, an improvement of the plasma generation efficiency can be done. 
     According to the fifth form of the present invention, because an annular recess position is formed at a periphery of said cathode so that said minute piece detached from said anode is retained and collected in said annular recess position, said minute piece fallen around said cathode periphery does not deposit and come into contact with said cathode, and a generation of short circuit between the cathode and the anode can be prevented beforehand reliably. 
     According to the sixth form of the present invention, a retention portion for said minute piece is installed beneath said cathode, and at the same time, an exposing portion that communicates with said retention portion is formed at a periphery of said cathode, so that said minute piece detached from said anode is retained and collected in said retention portion through said exposing portion. Because of this, said minute piece that have detached and fell in said cathode periphery does not deposit at all, and a generation of short circuit between the cathode and the anode can be prevented even more reliably. 
     According to the seventh form of the present invention, when the plasma generated by the plasma generation apparatus of any one of said first to sixth forms is transported through said plasma transport tube and supplied to said plasma processing portion so that a film formation processing, for example, is done, a stable operation of said plasma generation apparatus can be done without producing a short circuit between the cathode and the anode, and an improvement of the process efficiency of film formation can be carried out. 
     In plasma treatment, high purity plasma is used for doing film formation among others, and there is a need to carry out an improvement of the surface treatment precision. Among the factors that obstruct a generation of high purity plasma, there is one caused by droplets generated from the target (cathode) mixing with the plasma. Among this type of droplets, there exist electrically charged droplets bearing positive and/or negative charge (positive droplets and negative droplets) and neutral droplets that do not bear a charge. 
     A plasma processing apparatus concerning the present invention has a plasma generation apparatus comprising an anode on which a large number of said recesses and protrusions have been formed, and the operation efficiency can be improved by preventing a detachment of a large carbon flake without decreasing the plasma generation efficiency. Moreover, a high purification of the generated plasma can be realized by applying removal measures for neutral and electrically charged droplets using the eighth to twelfth forms. 
     According to the eighth form of the present invention, by interposing a starting end side insulator between said plasma generating portion and said plasma transport tube, and interposing a finishing end side insulator between said plasma transport tube and said plasma processing portion, a complete electrical independence is achieved by said plasma generating portion, said plasma transport tube, and said plasma processing portion. As a result, an electric influence from said plasma generating portion and said plasma processing portion toward the plasma transport tube is completely blocked, the plasma transport tube that is usually formed from a metal becomes constant in terms of the electric potential as a whole, and an electric potential difference does not exist in the plasma transport tube. Because there is no electric potential difference, an electrical force, based on electric potential difference, toward charged particles is not generated. Because electrically charged droplets are one type of charged particles, an electrical force does not act on electrically charged droplets in a plasma transport tube in a constant electric potential state, and therefore electrically charged droplets can be handled in the same manner as neutral droplets. Therefore, by means of the geometric removal method of neutral droplets described below, it becomes possible for electrically charged droplets to be removed together with neutral droplets while advancing through the plasma transport tube. Because of this, the plasma supplied from the plasma transport tube becomes a high purity plasma from which neutral droplets and electrically charged droplets have been removed by the neutral droplet removal structure, and by this high purity plasma, a high purity plasma treatment is made possible toward an object to be treated in the plasma processing portion. 
     According to the ninth form of the present invention, the plasma generating apparatus is offered in which said plasma transport tube is composed in a bent manner in three stages of a plasma straightly advancing tube connected to said plasma generating portion, a first plasma advancing tube connected in a bent manner to said plasma straightly advancing tube, a second plasma advancing tube diagonally arranged and connected at the finishing end of said first plasma advancing tube in a bent manner with a predetermined bending angle with respect to the tube axis of said first plasma advancing tube, and a third plasma advancing tube connected in a bent manner to the finishing end of said second plasma advancing tube so that the plasma is exhausted from a plasma outlet, and total length L from the target surface to the object to be treated is set to satisfy 900 mm≦L≦1350 mm. Furthermore in details, said length L is defined as the total length that is the sum of length L 0  from the target surface to the outlet of the plasma straightly advancing tube, length L 1  of the first plasma advancing tube, length L 2  of the second plasma advancing tube, length L 3  of the third plasma advancing tube, together with plasma effective distance L 4  that is the distance for the plasma to reach from the plasma outlet of said third plasma advancing tube to the object to be treated. That is to say, L=L 0 +L 1 +L 2 +L 3 +L 4 , and the detail is shown in  FIG. 7 , As thus described, because it is set so that said total length L satisfies 900 mm≦L≦1350 mm, as shown in  FIG. 20 , the film formation rate can be improved by shortening the plasma transport distance of the plasma advancing path furthermore than the conventional T-type plasma advancing paths and curved plasma advancing paths. Moreover, not merely the straightly advancing pathway is shortened, but neutral droplets are removed highly efficiently by said geometric structure of three stages of bent pathway. Furthermore, as stated above, electrically charged droplets are also removed highly efficiently by said geometric structure, and high purity plasma that can realize an improvement of surface treatment precision of film formation among others can be generated. 
     Said second plasma advancing tube is inclined in said bending angle (angle of inclination), and droplets can be blocked when the angle of inclination is large, but the film formation rate to the surface of the object to be treated decreases because the plasma density decreases. On contrary, when the angle of inclination is small, droplets intrude the treatment chamber, but the film formation rate to the surface of the object to be treated does not decrease because the decrease in the plasma density is small. Therefore, said angle of inclination can be chosen appropriately from the relation between the film formation rate and the tolerance for droplets. 
     Said bent pathway of three stages in the present invention by said plasma straightly advancing tube, said first plasma advancing tube, said second plasma advancing tube, and said third plasma advancing tube is comprised by connecting each tube on a same plane, or comprised by positioning them in three dimension spatially. 
     According to the tenth form of the present invention, said second plasma advancing tube is placed geometrically at the position away from the straight line of sight from the plasma outlet of said third plasma advancing tube to the plasma outlet side of said first plasma advancing tube. Because the droplets led out from said first plasma advancing tube are not exhausted directly from the plasma outlet of said third plasma advancing tube, but instead they collide with the pathway inner wall and are adhered and removed in said bent pathway process of three stages, the droplets adhering to the object to be treated can be largely reduced, and a plasma treatment becomes possible by high purity plasma from which droplets have been removed highly efficiently. 
     The outlet of said third plasma advancing tube may be connected directly to the outer wall surface of the plasma processing portion, or it may be positioned by inserting deeply in the inside of said outer wall surface. Furthermore, while maintaining the positional relationship between the outlet of said third plasma advancing tube and said outer wall surface, a rectifying tube and/or a deflection/oscillation tube could be installed between the second plasma advancing tube and the third plasma advancing tube. 
     According to the eleventh form of the present invention, θ≧θ 0  is satisfied when the angle of elevation from the tube cross section top end of the plasma entrance port side of said third plasma advancing tube to the tube cross section bottom end of the plasma outlet side of said first plasma advancing tube is defined as θ, and the angle of elevation from the tube cross section bottom end of the plasma outlet side of said third plasma advancing tube to the tube cross section top end of the plasma outlet side of said second plasma advancing tube is defined as θ 0 . Because of this, said second plasma advancing tube can be placed at the position off the straight line of sight from the plasma outlet of said third plasma advancing tube to the plasma outlet side of said first plasma advancing tube. Therefore, for example, in cases where said bent pathway of three stages is comprised by connecting on a same plane, a tube passage configuration can be realized in which droplets led out from said first plasma advancing tube are not directly exhausted by the plasma outlet of said third plasma advancing tube, and a plasma treatment using high purity plasma from which droplets have been removed highly efficiently becomes possible. 
     As explained above, needless to say, the outlet of said third plasma advancing tube may be connected directly to the outer wall surface of the plasma processing portion, or it may be positioned by inserting deeply in the inside of said outer wall surface. Also, needless to say, a rectifying tube and/or a deflection/oscillation tube could be installed between the second plasma advancing tube and the third plasma advancing tube. 
     According to the twelfth form of the present invention, the magnetic field generating means for plasma transportation that generates a magnetic field for plasma transportation is set up in each of said plasma straightly advancing tube, said first plasma advancing tube, said second plasma advancing tube, and said third plasma advancing tube, the deflection magnetic field generating means for deflecting said magnetic field for plasma transportation is attached in said first plasma advancing tube and/or said second plasma advancing tube, and the plasma stream is deflected toward the tube center side by the deflection magnetic field generated by said deflection magnetic field generating means. Because of this, the heterogeneity of said magnetic field for plasma transportation at the connecting section of said first plasma advancing tube and/or said second plasma advancing tube, that is to say, the trouble in which the additional magnetic field becomes strong at the inside of the bending portion due to the configuration of said magnetic field coil for magnetic field generation for plasma transportation, is deflected and adjusted by said deflection magnetic field, the plasma stream is guided to the tube passage center, the plasma density is held high, and a plasma treatment using high density, high purity plasma becomes possible. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross section outlined schematic diagram of a plasma processing apparatus in which plasma generation apparatus  1  of the present invention has been installed. 
         FIG. 2  is a cross-section schematic diagram of the surroundings of plasma generating portion  4  in plasma generation apparatus  1 . 
         FIG. 3  is a longitudinal sectional diagram showing the electrode cylindrical body of anode  3  for use in plasma generation apparatus  1 . 
         FIG. 4  is a longitudinal sectional diagram showing the details of the electrode cylindrical body of anode  3 . 
         FIG. 5  is a pattern diagram showing pattern examples of multiple divisions on an electrode cylindrical body of the present invention. 
         FIG. 6  is a longitudinal sectional diagram showing a variation in which a part of an anode inner wall has been multiply divided. 
         FIG. 7  is an outlined schematic diagram of a plasma processing apparatus concerning the present embodiment. 
         FIG. 8  is an outlined schematic diagram of a plasma processing apparatus concerning a different embodiment of the present invention. 
         FIG. 9  is an outlined schematic diagram of a plasma processing apparatus concerning another different embodiment of the present invention. 
         FIG. 10  is a schematic diagram of a bias power supply for use in the present invention. 
         FIG. 11  is an outlined schematic diagram of a plasma processing apparatus concerning the fourth embodiment of the present invention. 
         FIG. 12  is a placement diagram showing a placement state of movable yoke  129  concerning the fourth embodiment. 
         FIG. 13  is a schematic diagram showing a rotating adjustment mechanism of movable yoke  129 . 
         FIG. 14  is a schematic diagram showing slide and swing adjustment mechanisms of movable yoke  129 . 
         FIG. 15  is a model schematic diagram of a magnetic field coil for magnetic field generation for plasma transportation concerning the fourth embodiment. 
         FIG. 16  is a partially enlarged cross-sectional diagram of inner circumferential tube  161  concerning the fourth embodiment. 
         FIG. 17  is a plane view of a movable aperture  170  concerning the fourth embodiment, and an installation state diagram of aperture  170 . 
         FIG. 18  is an outlined schematic diagram of a plasma processing apparatus of the fifth embodiment, 
         FIG. 19  is an explanatory diagram of a magnetic field for scanning formed inside frustoconical tube (deflection/oscillation tube)  1108  concerning the fifth embodiment. 
         FIG. 20  is a relational diagram showing the relation of plasma transport distance with respect to the film formation rate. 
         FIG. 21  is an outlined schematic diagram of a conventional plasma processing apparatus. 
         FIG. 22  is a longitudinal cross-section diagram of the inner wall surface of a conventional electrode cylindrical body  214 . 
     
    
    
     DENOTATION OF REFERENCE NUMERALS 
       1  Plasma generation apparatus 
       2  Cathode 
       3  Anode 
       4  Plasma generating portion 
       5  Trigger electrode 
       6  Plasma advancing path 
       7  Bending portion 
       8  Bending magnetic field generator 
       9  Droplet advancing path 
       10  Droplet collecting portion 
       11  Baffle 
       12  Baffle 
       13  Radially enlarged tube 
       14  Magnetic field generator 
       15  Plasma processing portion 
       16  Object to be treated 
       17  Baffle 
       18  Magnetic field generator 
       19  Baffle 
       20  Magnetic field generator 
       21  Target coil 
       22  Filter coil 
       23  Radially reduced tube 
       24  Rotation shaft 
       25  Power supply 
       26  Electricity conduction line 
       27  Electricity conduction line 
       28  Anode inner wall 
       29  Outer wall 
       30  Insulation member 
       31  Insulation member 
       32  Electric discharge surface 
       33  Tube passage end 
       34  Gap 
       35  Protruding portion 
       36  Retention portion 
       37  Groove 
       38  Groove 
       39  Protruding portion of small fragment 
       40  Carbon flake 
       41  Diffusing material 
       42  Annular recess position 
       43  Protruding portion 
       44  Diagonal direction groove 
       45  Lateral groove 
       46  Hexagonal protruding portion 
       47  Honeycomb groove 
       48  Anode 
       49  Lattice-like recess-protrusion pattern 
       50  Annular groove pattern 
       101  Plasma processing portion 
       102  Plasma generating portion 
       103  Plasma straightly advancing tube 
       104  First plasma advancing tube 
       105  Second plasma advancing tube 
       106  Third plasma advancing tube 
       107  Plasma outlet 
       108  Arrow 
       108   a  X-direction oscillating magnetic field generator 
       108   b  Y-direction oscillating magnetic field generator 
       109  Arrow 
       110  Cathode 
       111  Trigger electrode 
       112  Anode 
       113  Arc power supply 
       114  Cathode protector 
       115  Plasma stabilizing magnetic field generator 
       116  Insulation plate 
       117  Magnetic field coil 
       118  Magnetic field coil 
       119  Magnetic field coil 
       121  Magnetic field coil 
       122  Deflection magnetic field generating means 
       123  Deflection magnetic field generating means 
       124  Deflection magnetic field generating means 
       125   a  Gas inflow port 
       125   b  Exhaust port 
       127  Magnetic pole 
       128  Magnetic pole 
       129  Movable yoke 
       130  Deflection magnetic field generating coil 
       131  Guiding body 
       132  Guiding groove 
       133  Pin 
       134  Fastening nut 
       135  Slide member 
       136  Spacer 
       137  Adjusting portion main body 
       138  Slide groove 
       139  Pin 
       140  Fastening nut 
       141  Droplet collecting plate (baffle) 
       142  Droplet collecting plate (baffle) 
       143  Droplet collecting plate (baffle) 
       144  Droplet collecting plate (baffle) 
       160  Droplet collecting plate (part of a baffle) 
       161  Inner circumferential tube 
       162  Opening 
       163  Bias power supply 
       170  Aperture 
       171  Opening 
       172  Stopper 
       173  Screw 
       174  Protrusion 
       175  Tube 
       176  Engagement recess 
       177  Arrow 
       200  Plasma generating portion 
       201  Cathode 
       202  Trigger electrode 
       203  Anode 
       204  Plasma 
       205  Power supply 
       206  Plasma stabilizing magnetic field generator 
       207  Plasma stabilizing magnetic field generator 
       208  Plasma processing portion 
       209  Object to be treated 
       210  Gas introduction system 
       211  Gas exhaust system 
       212  Droplet collecting portion 
       213  Cathode material particle 
       214  Electrode cylindrical body 
       215  Circular groove 
       216  Protruding portion 
       217  The upper side 
       218  Diffusing material 
       219  Circular arc part 
       220  Carbon flake 
       1109  Outlet tube 
       1100  Plasma straightly advancing tube 
       1101  First plasma advancing tube 
       1102  Second plasma advancing tube 
       1103  Third plasma advancing tube 
       1104  Connecting port 
       1105  Plasma outlet 
       1106  Plasma outlet 
       1107  Rectifying tube 
       1108  Frustoconical tube 
       1110  Plasma outlet 
       1111  Arrow 
       1112  Arrow 
       1113  Magnetic field coil for scanning 
       1114  Rectifying magnetic field coil 
     A Plasma generating portion 
     A 1  Plasma generating portion container, 
     A 2  Target exchange portion 
     B Plasma transport tube 
     B 0  T-shaped transport tube 
     B 2  Second transport tube 
     B 23  Bending transport tube 
     B 3  Third transport tube 
     C Plasma processing portion 
     C 1  Installation position 
     C 2  Target positon 
     C 3  Processing portion container 
     CT Connection terminal 
     E Bias power supply 
     EA 1  Bias power supply for container 
     EA 2  Bias power supply for exchange portion container 
     EB Bias power supply for transport tube 
     EB 01 T Bias power supply for transport tube 
     EB 2  Bias power supply for second transport tube 
     EB 23  Bias power supply for bending transport tube 
     EB 3  Bias power supply for third transport tube 
     EC Bias power supply for processing portion 
     EW Bias power supply for object to be treated 
     FT Floating terminal 
     GND Ground 
     GNDT Grounding terminal 
     IFA Finishing end side insulator 
     II 1  The first middle insulator 
     ISA Starting end side insulator 
     IA Inter-container insulator 
     II 2  The second middle insulator 
     NVT Variable negative electric potential terminal 
     P 0  Plasma straightly advancing tube 
     P 1  First plasma advancing tube 
     P 2  Second plasma advancing tube 
     P 3  Third plasma advancing tube 
     P 4  Radially enlarged tube 
     PVT Variable positive electric potential terminal 
     S 1  Plasma outlet 
     S 2  Plasma entrance port 
     S 3  Plasma outlet 
     VT Variable terminal 
     W Work 
     BEST MODE FOR CARRYING OUT THE INVENTION 
     In the following, a multiply divided anode wall type plasma generation apparatus and plasma processing apparatus concerning an embodiment of the present invention is explained in detail, based on the attached figures. 
       FIG. 1  is a cross section outlined schematic diagram of a plasma processing apparatus in which plasma generation apparatus  1  of the present invention has been installed. In plasma generating portion  4 , a supply source of the plasma constituent material is made to be cathode  2  (a target), and cylinder-like anode  3  is arranged at the front side of cathode  2 . Trigger electrode  5  is installed so that it is free to rotate, whereby it can approach toward and retreat from cathode  2 . Anode  3  comprises an electrode cylindrical body in which the cylinder inner wall is made to have a multiply divided configuration. Plasma P is generated by causing an electric spark between cathode  2  and trigger electrode  5  under a vacuum environment, and generating a vacuum arc between cathode  2  and anode  3 . By the vacuum arc discharge in plasma generating portion  4 , vacuum arc plasma constituent particles such as target material ions, electrons, and cathode material neutral particles (atoms and molecules) are ejected, and at the same time, cathode material particles (subsequently referred to as “droplets D”) with size from less than submicron up to several hundred microns (0.01-1000 μm) are also ejected. The generated plasma P advances within plasma advancing path  6 , and it advances to the second advancing path by means of a magnetic field formed by bending magnetic field generators  8 ,  8  in bending portion  7 . At that instance, because droplets D are neutral electrically and therefore do not become influenced by a magnetic field, they advance straightly through droplet advancing path  9 , and are collected at droplet collecting portion  10 . A straightly advancing tube passage connecting with the second advancing path is installed in bending portion  7 , and in the inner wall of each advancing path of plasma P in droplet advancing path  9  among others, baffles  11 ,  12  and  17  are installed, on which droplets D collide and adhere. As well, magnetic field generator  18  generating a plasma advancing magnetic field is set up in said straightly advancing tube passage. 
     The second advancing path comprises radially enlarged tube  13  in which multiple baffles  12  have been installed in the inner wall, and magnetic field generator  20  that generates a plasma advancing magnetic field is set up in radially enlarged tube  13 . When plasma P advances through radially enlarged tube  13 , the remaining droplets D collide with and adhere to said baffle  12 , and thus droplets D are removed furthermore. Radially enlarged tube  13  is inclinedly arranged with respect to said straightly advancing tube passage. The finishing end of radially enlarged tube  13  is connected to plasma processing portion  15  through radially reduced tube  23 . Plasma P from which droplets D have been removed is supplied to plasma processing portion  15  by the magnetic field of magnetic field generator  14 ,  14 , and it can plasma-treat object to be treated  16 . Baffle  19  is also set up in radially reduced tube  23 . 
       FIG. 2  is a cross-section schematic diagram of the surroundings of plasma generating portion  4 . As shown in ( 2 A) of the same figure, trigger electrode  5  comprises a striker that is axle-supported so that it is free to swing with rotation shaft  24  as the axis. By power supply  25 , an electrical voltage is applied between anode inner wall  28 /trigger electrode  5  of the striker and the target of cathode  2  through electricity conduction lines  26 ,  27 . Plasma generating portion outer wall  29  does not come in contact with anode inner wall  28  because of insulation members  30 ,  31  mounted at the top and bottom ends of outer wall  29 , and thus electrical neutrality is maintained. Tube passage end  33  of plasma advancing path  6  is connected to the plasma outlet side of plasma generating portion outer wall  29 . The electrode cylindrical body of anode  3  is kept open in the cathode  2  side, and gap  34  is formed. Insulation member  30  corresponds to starting end side insulator IS that is explained below. 
     By separating the striker in the contact position as shown in solid line toward the separation direction, a vacuum arc discharge is induced between electric discharge surface  32  of cathode  2  and anode inner wall  28 . The striker swings after receiving a rotational drive force from a rotational drive source (not shown). When the striker in the separated position is put into contact with electric discharge surface  32 , the torque reaction force of the striker that has come in contact by the rotational drive source is detected, and the contact condition is confirmed. Furthermore, filter coil  22  is arranged at the plasma outlet side of plasma generating portion  4 , and plasma advancing magnetic field  132  is formed. Stabilizing magnetic field B 1  generated by target coil  21  is formed in reversed-phase (cusp) in comparison with plasma advancing magnetic field  132 , so that a generation of stable plasma becomes possible. As shown in ( 2 B) of  FIG. 2 , it is known that when stabilizing magnetic field B 1  generated by target coil  21  is in-phase (mirror), the stability of the arc spot decreases, but the generation efficiency of plasma improves. 
       FIG. 3  is a longitudinal sectional diagram showing the electrode cylindrical body of anode  3 .  FIG. 4  is a longitudinal sectional diagram showing the details of said electrode cylindrical body. 
     In the inner wall of electrode cylindrical body of anode  3 , recesses and protrusions are engraved in shape of a matrix by longitudinal and lateral grooves  37 ,  38 , and thus many protruding portions  35  are formed. Protruding portions  35  have a thin rectangular box-like configuration that is curved. Beneath gap  34  set up at the lower part of the electrode cylindrical body, retention portion  36  larger that the diameter of the cylinder is placed for collecting carbon flakes. 
     As shown in  FIG. 4 , when plasma P generated between cathode  2  and anode  3  is ejected further forward than cathode  2  and diffused, diffusing material  41  recrystallizes on the electrode cylindrical body inner wall, adheres and deposits, and it detaches as carbon flake  40 . In the present embodiment, because the electrode cylindrical body inner wall is multiply divided in shape of a matrix by means of longitudinal and lateral grooves  37 ,  38 , even if the diffusion plasma adheres and deposits on anode  3 , the size of the deposited matter is reduced by the deposited matter separation effect of the large number of protruding portions  35 , and a large or long deposited matter is not produced at all. Therefore, for example, because only a minute piece of carbon flake  40  detaches from a small protruding portion  39 , bridging of a detached deposited matter across cathode  2  and anode  3  does not occur, and a generation of short circuit between both electrodes can be prevented, contributing to a stable operation and an improvement of the operation efficiency of the plasma generation apparatus. The minute carbon flake  40  falls from gap  34  at the perimeter of cathode  2  toward beneath the arrow, and is collected in retention portion  36 . 
       FIG. 5  shows pattern examples of multiple divisions on an electrode cylindrical body. ( 5 A) of said figure is the lattice like matrix pattern used for the present embodiment. Carbon flakes grow according to the surface size of the protruding portions, and to increase the deposited matter separation effect, it is desirable that protruding portions  35  are as small as possible. Because the effective electrode surface area decreases if the multiple divisions are done excessively, it is sufficient to make the longest length L of protruding portions  35  at least shorter than width R of the gap between the cylinder inner wall and the cathode outer circumference (cf.  FIG. 4 ). Even if a carbon flake corresponding to said length is detached, it can reliably be dropped below the exposing portion of gap  34 , so that it can be collected. 
     A multiply divided pattern in the anode electrode cylindrical body is not limited to a lattice-like matrix pattern. For example, it can be a diagonally crossing pattern shown in ( 5 B) of  FIG. 5 , or an island-like pattern shown in ( 5 C) of the same figure. An example of a diagonally crossing pattern can be obtained by engraving diagonal direction grooves  44  against lateral grooves  45  in the cylinder inner wall, and forming protruding portions  43  having a rectangular box-like configuration that is curved. An example of an island-like pattern can be obtained by engraving honeycomb grooves  47  in the cylinder inner wall, and forming hexagonal protruding portions  46 . Among the island-like patterns, water drop-like patterns with round-shaped protruding portions are included. 
     Because carbon flakes merely detach by use of a multiply divided anode concerning the present embodiment, annular recess position  42  surrounding cathode  2  in the lower part of gap  34  may be set up instead of retention portion  36 , as shown by broken lines of  FIG. 3 , so that size-reduced carbon flakes may be collected. Although the frequency for flake collection increases in comparison with a large-scale retention portion  36 , it is advantageous in that the surrounding of cathode  2  can be made compact. 
     Deposited mass on an anode inner wall by diffusion plasma tends to increase nearby cathode  2  that is the supply source of the plasma constituent material. Therefore, it is not always necessary to make multiple divisions on the entire surface of the anode inner wall, but it is sufficient to make multiple divisions in either the entirety or a part of the inner wall, according to the size of the anode area or the anode cylindrical body. 
       FIG. 6  shows a variation in which a part of an anode inner wall has been multiply divided. In this variation, within the inner wall of the electrode cylindrical body of anode  48 , the half area near cathode  2  is made into a formation area of a lattice-like recess-protrusion pattern  49  shown above, and in the remaining half of the cylinder inner wall, annular groove pattern  50  is formed, in which multiple annular grooves are engraved in the forward direction of cathode  2 . Therefore, a size reduction of deposited matter can be realized by recess-protrusion pattern  49  in the half area near cathode  2 , and in the remaining cylinder inner wall, a large surface area is maintained for the anode protruding portions formed by annular groove patterns  50 . Because of this, a generation of a vacuum arc can be induced highly efficiently, a generation of short circuit between the cathode and the anode can be prevented, and at the same time, an improvement of the plasma generation efficiency can be done. 
     In a plasma processing apparatus concerning the present embodiment, plasma generation apparatus  1  comprising a multiply divided anode is provided, and an improvement of the operation efficiency is done by preventing a detachment of a large carbon flake without decreasing the plasma generation efficiency. Furthermore, it comprises a plasma high-purification configuration, in which neutral droplets and electrically charged droplets can be removed with higher efficiency. In the following, the plasma high-purification configuration in a plasma processing apparatus of the present embodiment is explained. In  FIGS. 7-9 , the explanation is done while focusing on the plasma transport pathway, and the configuration aside from that of the plasma transport pathway is illustrated in a simplified mode. 
       FIG. 7  shows an outlined scheme of the plasma transport pathway in a plasma processing apparatus of the present embodiment. In the plasma processing apparatus concerning the present embodiment, starting end side insulator IS is interposed between the plasma outlet in the cylindrical body of anode  3  and the plasma transport tube, finishing end side insulator IF is interposed between the plasma transport tube and plasma processing portion  15 , and thus plasma generating portion  1 , the plasma transport tube, and plasma processing portion  15  are mutually separated electrically so that an electric influence from plasma generating portion  1  and plasma processing portion  15  on the plasma transport tube is blocked. 
     It is composed of plasma generating portion A that generates the plasma supplied to plasma processing portion C (a chamber), and plasma transport tube B. Plasma generating portion A corresponds to plasma generating portion  4 . In plasma processing portion C, work (object to be treated by plasma) W is set up, a reactive gas is introduced as necessary by a gas introduction system connected into the chamber from gas inflow port G 1 , and reactant gas and plasma stream are exhausted from exhaust port G 2  by a gas exhaust system. Plasma generating portion A has a cathode (target) that generates plasma by vacuum arc discharge under a vacuum environment. Plasma transport path B comprises a tube passage that mobilizes plasma, and plasma transport path B also has a structure of a droplet removing portion that removes droplets produced as a byproduct from the cathode by its geometrical structure. This plasma transport path B is also a plasma stream distribution tube passage, and comprises plasma straightly advancing tube P 0  connected to plasma generating portion A, first plasma advancing tube P 1  connected in a bent manner to plasma straightly advancing tube P 0 , second plasma advancing tube P 2  inclinedly arranged and connected at the finishing end of first plasma advancing tube P 1  in a predetermined bending angle with respect to the tube axis, and third plasma advancing tube P 3  connected in a bent manner at the finishing end of second plasma advancing tube P 2  so that plasma is exhausted from the plasma outlet. Second plasma advancing tube P 2  corresponds to said second advancing path of  FIG. 1  comprising radially enlarged tube  13 . Outlet S 3  of said third plasma advancing tube P 3  is inserted deeply and extended inside the outer wall surface of said plasma processing portion C, but as shown in  FIG. 11  described below, said outlet S 3  may be directly connected to said outer wall surface through a flange (not shown). The connection type can be adjusted freely. 
     Plasma straightly advancing tube P 0  adheres and removes droplets advancing straightly from plasma generating portion A by colliding them against finishing end section E opposite plasma generating portion A, or against the tube inner wall. The plasma advancing length from said target position C 2  of plasma generating portion A to the outlet of plasma straightly advancing tube P 0 , that is to say, the connection point between plasma straightly advancing tube P 0  and first plasma advancing tube P 1 , is defined as L 0 . First plasma advancing tube P 1  communicates and connects toward the perpendicular direction at the side wall of the finishing end side of plasma straightly advancing tube P 0 . The plasma advancing length of first plasma advancing tube P 1  is defined as L 1 . Second plasma advancing tube P 2  is inclinedly arranged between first plasma advancing tube P 1  and third plasma advancing tube P 3 , and its plasma advancing length is defined as L 2 . Third plasma advancing tube P 3  is placed toward a parallel direction with respect to first plasma advancing tube P 1 , and its plasma advancing length is defined as L 3 . The plasma outlet of third plasma advancing tube P 3  is extended inside the plasma processing portion C. The plasma effective distance in which the plasma exhausted from the plasma outlet of third plasma advancing tube P 3  arrives at installation position C 1  of the object to be treated in plasma processing portion C is defined as L 4 . A plasma advancing path formed in a bent manner in three stages is formed by plasma straightly advancing tube P 0 , first plasma advancing tube P 1 , second plasma advancing tube P 2 , and third plasma advancing tube P 3 . 
     Around the outer circumference of each plasma advancing tube, a magnetic field coil (not shown) for generating a magnetic field for plasma transportation is wound with a purpose to transport plasma stream along the tube passage. By magnetic field generating means for plasma transportation comprising of magnetic field coil, a magnetic field for plasma transportation is generated in the whole three stages of said bent pathway, and the plasma transport efficiency is improved. Also, a baffle (not shown) for droplet removal is set up in the tube inner wall. 
     In the plasma advancing path concerning the above configuration, total length (plasma transport distance) L(=L 0 +L 1 +L 2 +L 3 +L 4 ), which is the sum of plasma advancing lengths L 0 -L 3  respectively of the interval from the target surface to the outlet of plasma straightly advancing tube P 0 , first plasma advancing tube P 1 , second plasma advancing tube P 2 , and third plasma advancing tube P 3 , together with plasma effective distance L 4 , is set to satisfy 900 mm≦L≦1350 mm. 
       FIG. 20  is a relational diagram showing the relation of the plasma transport distance with respect to the film formation rate. In the present embodiment, L is set to be 1190 mm, as shown in A 3  of  FIG. 20 . Under setting of this plasma transport distance, when a plasma exposure was done on one piece of substrate in the same manner as the above verification experiments for A 1  and A 2 , and a film formation of thickness of 3 nm was carried out, a film formation rate of about 1.5 nm/sec was obtained. 
     According to the present embodiment, the plasma transport distance in the above plasma advancing path is shortened further than a conventional T-shaped plasma advancing path (A 1  of  FIG. 20 ) and a curved plasma advancing path (A 2  of  FIG. 20 ), and thus the film formation rate can be improved. Moreover, not only the straight advancing path is shortened, but also droplets are removed with higher efficiency by said pathway bending in three stages, and thus high purity plasma that can realize an improvement of the surface treatment precision of film formation and such can be generated. That is to say, the plasma transport distance is shortened in comparison to the cases in which a plasma advancing path bent in a T-shape (A 1 ) and a bent plasma advancing path (A 2 ) were used, and moreover, a high film formation rate (about 1.5 nm/sec) can be obtained as a good film formation condition for use in semiconductor substrates. 
     In the present embodiment, the plasma advancing path consists of said bent pathway of three stages, and furthermore, by the tube passage placement shown in  FIG. 7  or  11 , an extremely good droplets removal effect is obtained. By this droplet removal effect, when plasma was irradiated for 4 seconds against a substrate (work W) with a size of 2.5 in (inch) width d 1 , 2.5 in (inch) length D 2 , and an arbitrary thickness t, the deposited number of droplets became less than 10-100. 
     Second plasma advancing tube P 2  is placed geometrically at a position off the straight line of sight from plasma outlet S 3  of third plasma advancing tube P 3  to the plasma outlet S 1  side of first plasma advancing tube P 1 . That is to say, when the angle of elevation from the tube cross section top end of the plasma entrance port S 2  side of third plasma advancing tube P 3  to the tube cross section bottom end of the plasma outlet S 1  side of first plasma advancing tube P 1  is defined as θ, and when the angle of elevation from the tube cross section bottom end of the plasma outlet S 3  side of third plasma advancing tube P 3  to the tube cross section top end of the plasma outlet S 2  side of second plasma advancing tube P 2  is defined as θ 0 , θ≧θ 0  is satisfied. 
     By the above geometric tube passage placement, straightly advancing droplets led out from first plasma advancing tube P 1  are prevented from directly intruding third plasma advancing tube P 3 , so that they cannot be exhausted from plasma outlet S 3  of third plasma advancing tube P 3 . Therefore, it becomes possible to adhere and remove the droplets by collision at the pathway inner wall during said bent pathway process of three stages, the adhesion mass of the droplets on the object to be treated can be reduced greatly as described above, and a plasma treatment by high purity plasma from which droplets have been removed with high efficiency can be done. 
     In the present embodiment, said bent pathway of three stages is connected and composed on a same plane, but even when the tube pathway is composed in a spatially bent manner in three stages, by the same geometric arrangement as above, a tube pathway arrangement can be realized in which the straightly advancing plasma is not exhausted directly from the plasma outlet of the third plasma advancing tube. 
     As shown by the broken lines, second plasma advancing tube P 2  may be built as radially enlarged tube P 4  whose inner diameter is greater than first plasma advancing tube P 1  and third plasma advancing tube P 3 . That is to say, second plasma advancing tube P 2  is set up as radially enlarged tube P 4 , first plasma advancing tube P 1  is set up as an introduction side radially reduced tube connected to the plasma introduction side starting end of radially enlarged tube P 4 , and third plasma advancing tube P 3  is set up as a discharge side radially reduced tube connected to the plasma discharge side finishing end of radially enlarged tube P 4 . If radially enlarged tube P 4  is positioned midway, the plasma stream introduced from the introduction side radially reduced tube into the radially enlarged tube is diffused by the diameter-increasing effect of the plasma advancing path by radially enlarged tube P 4 . By the diffusion of this plasma stream, the droplets mixed with the plasma diffuse inside the radially enlarged tube P 4 , and are collided with, adhered to, and collected at the inner side wall of radially enlarged tube P 4 . Also, when the plasma stream in radially enlarged tube P 4  is exhausted, the droplets scattered in the radially enlarged tube inner wall surface side are collided with, adhere to, and collected by the step portion by the diameter-narrowing effect from radially enlarged tube P 4  to discharge side radially reduced tube, and thereby the droplets are not rejoined with the plasma stream, and a re-mixture of droplets can be prevented. Therefore, the droplets can be adhered to the internal side wall of radially enlarged tube P 4 , and thus can be collected sufficiently. Because of this, the droplets can be removed efficiently inside the tube path of first plasma advancing tube P 1 , second plasma advancing tube P 2 , and third plasma advancing tube P 3 . Also, when the central axes of radially enlarged tube P 4  and the introduction side radially reduced tube and/or the discharge side radially reduced tube are set off instead of being lined up, the droplets become easy to separate from the plasma stream, and the capture effect of droplets increases even more. Moreover, just by forming radially enlarged tube P 4  in the plasma advancing path, a droplet removing portion can be constituted easily and cheaply. 
     Said bent structure in three stages and angle relation θ≧θ 0  are mainly for providing the geometric structure of plasma transport path B installed in order to remove droplets advancing straightly, such as neutral droplets. Because electrically charged droplets are influenced by the electric effect and magnetic action from the environment, they may deviate from straight advancement in an electromagnetic field because of the electric field and/or the magnetic field. Therefore, in order to remove the electrically charged droplets, it is necessary to equip with a mechanism to intentionally remove in particular the electric potential difference from the plasma transport path. Because a magnetic field for plasma transport is necessary by all means, it is difficult to remove a magnetic field in a plasma device. Because the electric force towards the electrically charged droplets can be erased when the electric potential difference is removed, in this case the electrically charged droplets have a property of advancing straightly in the same manner as neutral droplets, and it becomes possible to remove the electrically charged droplets too by the previously described geometrical structure. 
     The plasma processing apparatus of present embodiment has a structure for removal of electrically charged droplets. Plasma generating portion A and plasma transport tube B are mutually insulated electrically by starting end side insulator IS, and moreover, plasma transport tube B and plasma processing portion C are mutually insulated electrically by finishing end side insulator IF. As a result, plasma transport tube B does not receive an electric influence from plasma generating portion A and plasma processing portion C at all, and plasma transport tube B is set so that the electric potential is constant throughout. As mentioned above, plasma transport tube B comprises plasma straightly advancing tube P 0 , first plasma advancing tube P 1 , second plasma advancing tube P 2 , and third plasma advancing tube P 3 , and because the electric potential becomes constant throughout the tube arrangement, no electric potential difference exists at all inside plasma transport tube B, and the electrically charged droplets do not receive at all an electric force from an electric potential difference inside plasma transport tube B. Therefore, electrically charged droplets too are removed inside plasma transport tube by the previously described structures in three stages and the angle relation θ≧θ 0 , in the same manner as neutral droplets. 
     Also, a bias power supply can be additionally installed in each component of present plasma processing apparatus. In  FIG. 7 , bias power supply EA 1  for container is installed at plasma generating portion container A 1 , bias power supply EB for transport tube is provided near plasma transport tube B, bias power supply EC is provided at processing portion container C 3  that is a housing of plasma processing portion C for processing portion, and bias power supply EW for portion for object to be treated is provided near work W. 
     Each bias power supply EA 1 , EB, EC, and EW has a same structure, and this structure is explained by using  FIG. 10 .  FIG. 10  is the structural diagram of a bias power supply used in the present invention. Connection terminal CT is a terminal connected to each component. Variable terminal VT attached to connection terminal CT can be varied in four stages. The receiving side terminal of four stages comprises floating terminal FT, variable positive voltage terminal PVT, variable negative voltage terminal NVT, and grounding terminal GNDT. When variable terminal VT is connected to floating terminal FT, floating terminal FT is in an electrically floating state, and it is not connected to any part. When variable terminal VT is connected to variable positive voltage terminal PVT, a positive electric potential with respect to GND (the ground side) is applied to the component parts in a manner that it can be varied in magnitude (0 to +50V). When variable terminal VT is connected to variable negative voltage terminal NVT, a negative electric potential with respect to GND (the ground side) is applied in a manner that it can be varied in magnitude (0 to −50V). When variable terminal VT is connected to grounding terminal GNDT, the component part is grounded. 
       FIG. 7  shows a suitable electric potential placement, plasma generating portion container A 1  is set up at GND by said bias power supply EA 1  for containers, plasma transport tube B is set in an electric floating state by bias power supply EB for transport tube, processing component container C 3  is set up at GND by bias power supply EC for processing component, and work W is set in an electric floating state by bias power supply for portion for object to be treated EW. Because plasma generating portion container A 1  is insulated from the arc power supply for plasma generation, a safety design is done on plasma generating portion container A 1  grounded by GND, for safety even upon a contact by a worker. Because processing component container C 3  too is grounded by GND, it is safe even if a worker comes in contact with it. Because plasma transport tube B is in an electric floating state, and the electric potential is constant as a whole, there is no electric potential difference within plasma transport tube B as described above, and electrically charged droplets too can be surely removed in the same manner as neutral droplets by the geometrical structure for droplets removal. Work W set to an electric floating state also has a constant electric potential as a whole, therefore the electric effect on the plasma is not unbalanced, and the plasma can be received evenly throughout the entire surface. 
       FIG. 8  is an outlined schematic diagram of a plasma processing apparatus concerning a different embodiment of the present invention. The first difference with the embodiment in  FIG. 7  is that target exchange portion container A 2  has been set up at the bottom of plasma generating portion container A 1  through inter-container insulator IA, and bias power supply EA 2  for exchange portion container has been attached at target exchange portion container A 2 . In target interchange portion container A 2 , a reserve target (not shown) is built in as a replacement when the target in plasma generating portion A has worn out, and at the same time, an exchange mechanism (not shown) is built in. The second difference is that plasma transport tube B is split into T-shaped transport tube B 01  and bending transport tube B 23  by first middle insulator II 1 , bias power supply EB  23  for bending transport tube is attached at bending transport tube B 23 , and bias power supply EB  01  for T-shaped transport tube is attached at T-shaped transport tube B 01 . Otherwise it is completely same as  FIG. 7 , and the working effect of the difference is described in particular as follows. 
     Bias power supply EA 2  for exchange portion container is grounded at GND, and it is designed for safety even in a case of contact by a worker. Bias power supply EA 1  for the container of plasma generating portion A is set to an electric floating state, so that the electric effect toward the plasma is erased, and a stable plasma generation is promoted. Bias power supply for T-shaped transport tube is connected to variable negative voltage terminal NVT of  FIG. 10 , and T-shaped transport tube B 01  is dropped to a negative electric potential. It was found experimentally that the removal efficiency of electrically charged droplets increased when this negative electric potential was adjusted within a range of −5 to −10V. Bias power supply EB 23  for bending transport tube is connected to GND. In this the second form, as the location of the bias power supply is varied from EA 2 →EA 1 →EB→EB  23 , the electric potential of the tubing work varies from GND→floating state→(−5 to −10V)→GND, and it became clear from the current experimental examples that this change in the electrical potential is effective for removal of electrically charged droplets. The reason is not clear, but it can be thought that when the electric potential is varied to be GND→negative electric potential→GND, positive droplets are adsorbed electrically by the transport tube in the first GND→negative electric potential change, and negative droplets are adsorbed electrically by the transport tube in the next negative electric potential→GND change. 
       FIG. 9  is an outlined schematic diagram of a plasma processing apparatus concerning another different third embodiment of the present invention. The difference with  FIG. 8  is that bending transport tube B 23  has been split into second transport tube B 2  and third transport tube B 3  by second intermediate insulator II 2 . As a result, bias power supply EB 2  for second transport tube has been attached to second transport tube B 2 , and bias power supply EB 3  for third transport tube has been attached to third transport tube B 3 . Otherwise, it is completely same as  FIG. 8 , and the working effect of the difference is described in particular as follows. 
     In  FIG. 9 , bias power supply EB 2  for second transport tube is grounded by GND, and bias power supply EB 3  for third transport tube is connected to variable negative voltage terminal NVT of  FIG. 10  so that it is set to a negative electric potential. It was obtained experimentally that it becomes favorable if the negative electric potential of bias power supply EB 3  for third transport tube is adjusted within a range of 0 to −15V. In this third embodiment, as the location of the bias power supply varies from EA 2 →EA 1 →EB 01 →EB 2 →EB 3 , the electric potential of its tubing work varies from GND→floating state→(−5 to −10V)→GND→negative electric potential. It became clear from current experimental examples that this electric potential variation is effective for removal of electrically charged droplets. The reason is not clear, but it can be thought that when the electric potential changes from GND→negative electric potential→GND→negative electric potential, positive droplets are adsorbed electrically by the transport tube in the first GND→negative electric potential change, negative droplets are adsorbed electrically by the transport tube in the next negative electric potential→GND change, and furthermore, the remaining positive droplets are adsorbed electrically by the transport tube in the next GND→negative electric potential change. 
     As explained above, the variable positive electric potential of each bias power supply EW, EC, EB 3 , EB 2 , EA 1 , EA 2 , and EB 01  can be adjusted within a range of 0 to +50V, and the variable negative electric potential is adjusted within a range of 0 to −50V. The electric potential of each bias power supply is varied and adjusted so that the droplet removal efficiency of the apparatus as whole is maximized within these electric potential ranges. 
     Next, an installation example of magnetic field coils that are suitable for a plasma processing apparatus in the present invention is explained, as well as an installation example of baffles (collecting plates) for droplet removal.  FIG. 11  is an outlined schematic diagram of a plasma processing apparatus concerning the fourth embodiment of the present invention. An apparatus of  FIG. 11  is the apparatus of  FIG. 8  with installation at the outer tube circumference of a magnetic field coil generating a magnetic field for plasma transportation. Also, it shows a plasma processing apparatus in which baffles for droplet removal are set up in the tube inner wall. In this embodiment, the connection mode is adopted in which the outlet of the third plasma advancing tube is directly connected to the outer wall surface of plasma processing portion  1 . In the same manner as  FIG. 8 , inter-container insulator IA, starting end side insulator IS, first middle insulator II 1 , and finishing end side insulator IF are placed, and they comprise the electric insulation of the apparatus as a whole. Also, the member reference numerals are shown as alphabetical characters in  FIG. 8 , but the member reference numerals are shown as numerical characters in  FIG. 11 . However, this is not a substantive difference. Also, an alphabetical reference numeral shows a same member in  FIG. 8  as in  FIG. 11 , and because the configuration and the working effect are already described in  FIG. 8 , the explanation of the equivalent parts is omitted in  FIG. 11 , and therefore, the structural geometry of droplet removal is mainly explained below. 
     Plasma processing apparatus of  FIG. 11  comprise plasma processing portion (chamber)  101  equipped with gas inflow port  125   a  and exhaust port  125   b,  a plasma processing apparatus comprising plasma generating portion  102  generating plasma to be supplied to plasma processing portion  101 , together with plasma transport tubes. A plasma transport tube comprises a plasma distribution tube passage in which a droplet removing portion for removing droplets is positioned, just as in  FIG. 8 . In the following, because the structure of plasma transport tube B in itself constitutes a droplet removing portion, “droplet removing portion” signifies plasma transport tube B that has a droplet removal structure. The droplet removing portion of the present fourth embodiment comprises plasma straightly advancing tube  103  connected to plasma generating portion  102 , first plasma advancing tube  104  connected in a bent manner to plasma straightly advancing tube  103 , second plasma advancing tube  105  diagonally arranged and connected at the end of first plasma advancing tube  104  in a predetermined bending angle against its tube axis, and third plasma advancing tube  106  connected in a bent matter at the finishing end of second plasma advancing tube  105  so that it exhausts plasma from plasma outlet  107 . 
     The plasma transport tube comprising plasma straightly advancing tube  103 , first plasma advancing tube  104 , second plasma advancing tube  105 , and third plasma advancing tube  106  is formed in a bent manner in three stages, just like the plasma transport tube of FIG,  8 . Plasma outlet  107  of third plasma advancing tube  106  is connected to plasma introduction port of plasma processing portion  101 . Also, second plasma advancing tube  105  is placed geometrically at a position off the line of sight from plasma outlet  107  of third plasma advancing tube  106  to the plasma outlet side of first plasma advancing tube  104 , in the same manner as  FIG. 8 . That is to say, when, as shown by arrow  109  depicted by a dashed line, the angle of elevation from the tube cross section bottom end of plasma outlet  107  side of third plasma advancing tube  106  to the tube cross section top end of the plasma outlet side of second plasma advancing tube  105  is defined as θ 0 , angle of elevation (θ), as shown by arrow  109 , from tube cross section top end of the plasma entrance port side of third plasma advancing tube  106  to the tube cross section bottom end of the plasma outlet side of first plasma advancing tube  104 , satisfies θ≧θ 0 . By the same geometric tube passage placement as  FIG. 8 , a direct intrusion of straightly advancing droplets led out from first plasma advancing tube  104  into third plasma advancing tube  106  is prevented, so that they do not get exhausted from plasma outlet  107  of third plasma advancing tube  106 . 
     Plasma generating portion  102  comprises cathode (cathode)  110 , trigger electrode  111 , inner wall multiply divided anode (anode)  112 , arc power supply  113 , cathode protector  114 , and plasma stabilizing magnetic field generator (an electromagnetic coil or a magnet)  115 . Cathode  110  is the supply source of the plasma constituent, and its formation material is not limited particularly as long as it is a solid having electroconductivity. A simple metal, an alloy, a simple inorganic substance, an inorganic compound (metallic oxide/nitride) and such can be used individually or as a mixture of two or more substances. Cathode protector  114  electrically insulates parts other than evaporating cathode surface, and prevents a backward diffusion of plasma generated between cathode  110  and anode  112 . The formation material of anode  112  is not limited particularly, as long as it does not evaporate at the plasma temperature, and it is a nonmagnetic material that is a solid having electroconductivity. Also the configuration of anode  112  is not limited particularly, as long as it does not obstruct an advancing of arc plasma as a whole. Furthermore, plasma stabilizing magnetic field generator  115  is placed around the circumference of plasma generating portion  102 , and it stabilizes the plasma. When arc stabilization magnetic field generator  115  is placed so that the applied magnetic field on the plasma is in mutually reverse direction (cusp form), the plasma is stabilized further. Also, when arc stabilization magnetic field generator  115  is placed so that the applied magnetic field on the plasma is in mutually same direction (mirror form), the deposition rate by the plasma can be improved. Furthermore, plasma generating portion  102  and each plasma tube path are electrically insulated by plasma generating portion side insulation plate  116 , and the construction is such that, even if a high voltage is applied to plasma generating portion  102 , the portions at forward of plasma straightly advancing tube  103  is in an electrically floating state, so that plasma does not receive an electrical influence inside the plasma advancing path. Also, a processing component side insulation plate (finishing end side insulator IF) is placed between third plasma advancing tube  106  and plasma processing portion  101 , the whole of the duct portion for plasma transportation from plasma straightly advancing tube  103  to third plasma advancing tube  106  is set to an electrically floating state, and constructed so that the transported plasma is not influenced by an external power supply (high voltage source and/or GND). 
     In plasma generating portion  102 , an electric spark is triggered between cathode  110  and trigger electrode  111 , a vacuum arc is generated between cathode  110  and anode  112 , and plasma is generated. Constituent particles of this plasma includes vaporized material from cathode  110 , and charged particles originating from the vaporized material and the reactant gas (ion, electron), together with molecules in pre-plasma state, and neutral particles such as atoms. Also, at the same time that plasma constituent particles are ejected, droplets with size from less than submicron to several hundred micron (0.01-1000 μm) are ejected. These droplets form a mixed state with plasma stream  126 , and move inside the plasma advancing path as droplet mixture plasma. 
     At the plasma transport tube comprising plasma straightly advancing tube  103 , first plasma advancing tube  104 , second plasma advancing tube  105 , and third plasma advancing tube  106 , a magnetic field generating means for plasma transportation comprising magnetic field coils  117 ,  118 ,  119 ,  120  wound around each tube circumference is installed. The plasma transport efficiency can be improved by generating a magnetic field for plasma transportation throughout the entire three stages of said bent pathway. 
     Because the plasma advancing path is formed in a bent manner in three stages, magnetic field coil  121  generating a bending magnetic field and deflection magnetic field generating means  123  are installed at the tube connecting portion of first plasma advancing tube  104  and second plasma advancing tube  105 , and they bend and guide the plasma stream by the bending magnetic field. Because a coil for bending magnetic field cannot be wound evenly at the connecting section of first plasma advancing tube  104  and second plasma advancing tube  105 , heterogeneity of the magnetic field is produced in which the bending magnetic field becomes strong inward of the bending portion. To eliminate this uneven magnetic field, deflection magnetic field generating means  122 ,  124  are provided by first plasma advancing tube  104  and second plasma advancing tube  105 . 
     Deflection magnetic field generating means  122 ,  124  consist of deflection magnetic field generating coil  130  and movable yoke  129 .  FIG. 12  shows a state in which movable yoke  129  is arranged around the outer circumference of the second plasma advancing tube  105 . Around movable yoke  129 , deflection magnetic field generating coil  130  is wound, and it has a pair of magnetic poles  127 ,  128 . A deflection magnetic field is generated between magnetic poles  127 ,  128 , and applied toward the plasma in second plasma advancing tube  105 . 
     Deflection magnetic field generating means  122 ,  124  include an adjustment mechanism, in which movable yoke  129  is adjusted by sliding along the tube axis direction, rotating along the circumferential direction, and swinging toward the tube axis direction. 
       FIG. 13  shows a rotating adjustment mechanism of movable yoke  129  positioned around the outer circumference of first plasma advancing tube  104 . The rotating adjustment mechanism comprises guide body  131  in which arc-like guiding grooves  132  that rotationally adjust movable yoke  129  in circumferential direction are installed in four places. Pins  133  set up at movable yoke  129  are inserted into guiding groove  132 , and by sliding pins  133  in the tube circumferential direction, movable yoke  129  can be rotationally adjusted within angle adjustable range θ 1  of less than or equal to 90 degrees. After the adjustment, the adjustment angle can be maintained by tightening pins  133  to guiding body  131 . 
       FIG. 14  shows an adjustment mechanism in which movable yoke  129  positioned circumferentially around the outer circumference of second plasma advancing tube  105  is adjusted by sliding toward the tube axis direction and by swinging toward the tube axis direction. Guiding body  131  is supported by slide member  135  in the state in which movable yoke  129  is fastened and held through spacer  136 . Slide member  135  has straight slide groove  138  along the tube axis direction of second plasma advancing tube  105 , and it is fastened to adjusting portion main body  137 . Slide groove  138  is formed parallel to the inclination center line of second plasma advancing tube  105 . The slide groove set up on first plasma advancing tube  104  is formed horizontally along the center line of first plasma advancing tube  104 . Pin  139  set up on guiding body  131  is inserted into guiding groove  138 , and by sliding pin  139  along the tube axis direction, movable yoke  129  of guiding body  131  can be slide-adjusted throughout almost the entire tube length of the second plasma advancing tube. After the adjustment, its adjusted position can be maintained by tightening pin  139  to slide member  135  with fastening nut  140 , Also, guiding body  131  is supported on slide member  135  so that it is free to rotate around the axis of pin  139 , in a state in which it fastens and holds movable yoke  129 . Movable yoke  129  can be swing-adjusted (tilt angle adjustment) toward the tube axis direction by rotating around the axis of pin  139 . After the adjustment, the adjustment tilt angle can be maintained by tightening pin  139  to slide member  135  with fastening nut  140 . The adjustable tilt angle is 5° toward the first plasma advancing tube  104  side, and 30° toward the opposite side. 
     Because deflection magnetic field generating means  122 ,  124  make possible to adjust movable yoke  129  in a sliding manner in the tube axis direction, a rotating manner in the circumferential direction, and a swinging manner in the tube axis direction, a removal of the heterogeneity of the magnetic field for plasma transportation can be carried out by a fine adjustment by said deflection magnetic field through adjusting the position or the angle of movable yoke  129 , and an optimum plasma advancing path comprising a geometrical arrangement of said bent pathway in three stages can be realized. 
     ( 15 A) of  FIG. 15  schematically shows state  119 A in which a magnetic field coil for magnetic field generation for plasma transportation is wound in a circle M 1 -like configuration around an inclinedly arranged second plasma advancing tube  105  along its inclination axis. In this case, as shown by the hatched lines in the figure, gaps are formed near the connecting portions with other tubes ( 104  or  106 ) in which the coil is not wound, producing a heterogeneity in the magnetic field, and reducing the plasma transport efficiency. 
     In the present embodiment, magnetic field coil  119  wound around the outer tube circumference of second plasma advancing tube  105  comprises a magnetic field coil wound elliptically along the inclination axis outside its outer tube circumference. ( 15 B) of  FIG. 15  schematically shows state  119 B in which magnetic field coil  119  for magnetic field generation for plasma transportation is wound in an oval M 2 -like configuration around an inclinedly arranged second plasma advancing tube  105  along its inclination axis. Because a gap such as the hatched areas in ( 15 A) is prevented by setting up magnetic field coil  119  wound in an oval M 2 -like configuration on second plasma advancing tube  105 , a plasma treatment using a high density and high purity plasma can be made possible by densely winding a magnetic field coil to the inclined surface of second plasma advancing tube  105  and improving the plasma transport efficiency without generating an uneven magnetic field. 
     To the plasma transport tube comprising plasma straightly advancing tube  103 , first plasma advancing tube  104 , second plasma advancing tube  105 , and third plasma advancing tube  106 , droplet collecting plates (baffles)  141 ,  142 ,  143 ,  144  are implanted on each respective tube inner wall surface. Structure of each collecting plate is explained in detail in the following. 
       FIG. 16  is a partially enlarged cross-sectional view of inner circumferential tube  161  having droplet collecting plate  160 . Inner circumferential tube  161  is built inside each plasma tube path ( 103 - 106 ), and a few droplet collecting plates  160  are implanted into its inner wall. Plasma stream circulation opening  162  is formed in the center of droplet collecting plate  160 . The plasma flows in from the upper part of the figure, and passes through opening  162 . Angle of inclination a of droplet collecting plate  160  is set within the range of 15-90°, but 30-60° is suitable according to experience, and it is set to α=60° in this embodiment. By this angle of inclination, the droplets separated from the plasma stream are reflected repeatedly by droplet collecting plates  160 , and are adhered and collected reliably. 
     The droplet adhesion surface area of inner circumferential tube  161  is increased by multiple droplet collecting plates  160 , and the scattered droplets can be adhered and collected in large quantities reliably. Because, in a plasma transport tube, the installation number of droplet collecting plates  160  is restricted by the limit of the tube length of inner circumferential tube  161 , in order to increase the droplet removal area, it is preferable to do a rough surface processing on the surface of droplet collecting plates  160 , and thus form rough surfaces having innumerable unevenness. That is to say, by roughening the surface of droplet collecting plates  160 , the capture area of droplet collecting plates  160  is increased, and the collection efficiency can be improved. Also, the droplets collided in the recesses are adhered reliably in the recesses, and the droplet collection efficiency increases markedly. Linear pattern processing and pearskin processing can be used for the surface-roughening processing. For a linear pattern processing method, for example, a polishing treatment with an abrasive paper is used. For example, in a pearskin processing method, a blast treatment by alumina, shots, grids, glass beads and such is used. Especially, a microblast processing, in which particles of a few microns are accelerated and nozzle-sprayed, can apply a minute unevening processing on the small surfaces of droplet collecting plates  160 . 
     The implanting area of droplet collecting plates  160  is preferably greater than or equal to 70% of the tube inner wall surface area. In the case of  FIG. 8 , the implanting area is made to be about 90% of the tube inner wall surface area. The scattering droplets can be adhered and collected reliably in a large quantity by the increase of the droplet adhesion surface area inside the tube for the plasma advancing path, and thus a high purity of the plasma flow can be realized. 
     Droplet collecting plates  160  are shielded electrically from the tube wall of each plasma advancing tube. To inner circumferential tube  161 , inner circumferential tube bias power supply  163  is connected as bias voltage application means, and inner circumferential tube  161  can be set to positive electric potential, set to negative electric potential, or grounded to CND. In a case where the bias electric potential of inner circumferential tube  161  is a positive electric potential, it has an effect of pushing the positive ions of the plasma in the transportation direction, and in a case of a negative electric potential, it has an effect of pushing the electrons of the plasma in the transportation direction. The choice of either the positive or the negative is chosen toward the way in which the plasma transportation efficiency is not decreased, and it is decided from the state of the plasma. The electric potential strength is variable too, and it is usually chosen to set inner circumferential tube  161  to +15V from the standpoint of the transportation efficiency. By applying a bias voltage to each droplet collecting plate, its bias electric potential is adjusted, and attenuation of the plasma can be thus suppressed, thereby increasing the plasma transportation efficiency. 
     In second plasma advancing tube  105 , one or more apertures  170  movable along the tube axis direction may be arranged. Said aperture  170  has a structure in which the installation position can be varied along the tube axis direction in second plasma advancing tube  105 . A structure that can be moved both forward and backward is acceptable, and a structure that can be moved in only one direction is also acceptable. Because it is movable, the installation position of the aperture can be adjusted, and it also can be removed and washed. This aperture  170  has an opening of a predetermined area at the center, and the droplets are collided and captured on the peripheral wall surface of this opening, while the plasma passing through said opening advances. Said opening may be set up at the center, or it may be set up at an eccentric position. It can be designed in various manners. Therefore, if multiple apertures  170  are installed movably in second plasma advancing tube  105 , the removal efficiency of the droplets increases, and the plasma purity can be improved. In the following, an aperture movable in one direction and using flat springs is shown. 
     ( 17 A) of  FIG. 17  is a plane view of a movable aperture  170 , and ( 17 B) of said figure shows an installation state of aperture  170 . Aperture  170  has a ring form having opening  171  of a predetermined area at the center. Here, the shape of said opening can be designed in a circular or an oval shape among others, depending on the placement configuration. At 3 locations of the surface of aperture  170 , stoppers  172  comprising outward-protruding elastic pieces (for example, flat springs) are fastened by screws  173 , but the fastening method can be adopted freely, such as welding. Protrusions  174  of the elastic pieces are bent downward. As shown in ( 17 B) of  FIG. 17 , in the tube  175  inner wall of second plasma advancing tube  105 , engagement recesses  176  for retaining aperture  170  are engraved beforehand in form of a circle. Engagement recesses  176  are set up in multiple numbers along the longitudinal direction of tube  175 . When aperture  170  is inserted into tube  175  in the direction of arrow  177  while protrusions  174  of the elastic pieces are bent downward, stoppers  172  move along the tuber inner circumference surface while they push and bend. The direction of the plasma stream is the opposite direction of arrow  177 . Furthermore, when aperture  170  is pushed toward the direction of arrow  177 , protrusions  174  of stoppers  172  spread at engagement recess  176  by the elastic directional force, fit into engagement recess  176 , and are locked. Stopper  172  cannot be moved in reverse in this locked state, and aperture  170  can be set in this locked position. When the set position is to be changed, the lock on stoppers  172  is removed upon pushing aperture  170  furthermore toward the direction of arrow  177 , so that protrusions  174  can again be fitted in and locked on the next engagement recess  176 . 
     Because aperture  170  has a structure in which it is movable to an arbitrary set position inside second plasma advancing tube  105 , droplets can be collected by the decrease in the diameter of second plasma advancing tube  105  by aperture  170 , and moreover, the set location can be changed appropriately so that the quantity of collection can be adjusted optimally, which contributes to an improvement in the droplet removal efficiency. The set number of apertures  170  is 1, 2 or more. In addition, opening  171  can be set up not only in the center of aperture  170 , but it is possible to place it eccentrically in order to add a function to make the plasma flow inside the tube meander. 
     A ring shaped aperture may be arranged in a connecting section in the plasma advancing path comprising plasma straightly advancing tube  103 , first plasma advancing tube  104 , second plasma advancing tube  105 , and third plasma advancing tube  106 . In the same manner as aperture  170 , by arranging this aperture for connecting section, the droplets included in the plasma stream can be collected in greater quantity, and the droplet removal efficiency can be improved, by reducing, making eccentric, or both reducing and making eccentric the tube diameter of the plasma advancing path. 
     In the plasma generating apparatuses of  FIGS. 7 and 11 , third plasma advancing tube  106  of the last stage is built with an even tube diameter, but it is preferable to increase further the density of the plasma stream passed through the bent pathway and exhausted from second plasma advancing tube  105 , at third plasma advancing tube  106 . Shown below is an embodiment in which a further high densification function is provided in third plasma advancing tube  106 . 
       FIG. 18  shows the outlined scheme of a plasma processing apparatus of the fifth embodiment. The plasma processing apparatus of  FIG. 18 , in the same manner as  FIG. 11 , has a plasma generating apparatus comprising a plasma generating portion (not shown) for generating plasma to be supplied to plasma processing portion  101 , and a plasma transport tube. The droplet removing portion set up in the plasma transport tube, in the same manner as  FIG. 8 , comprises plasma straightly advancing tube  1100  connected to the plasma generating portion, first plasma advancing tube  1101  connected to plasma straightly advancing tube  1100  in a bent manner at connecting port  1104 , second plasma advancing tube  1102  inclinedly arranged and connected at the finishing end of first plasma advancing tube  1101  in a predetermined bending angle against its tube axis, and third plasma advancing tube  1103  connected in a bent manner at the finishing end of second plasma advancing tube  1102  so that plasma is exhausted from plasma outlet  1106 . In addition, although not illustrated, droplet collecting plates and magnetic field coils for plasma transportation magnetic field formation are arranged in the plasma transport tube . 
     The plasma transport tube comprising plasma straightly advancing tube  1100 , first plasma advancing tube  1101 , second plasma advancing tube  1102 , and third plasma advancing tube  1103  is formed in a bent manner in three stages, in the same manner as the plasma advancing paths of  FIGS. 7 and 11 . Third plasma advancing tube  1103  comprises rectifying tube  1107  connected at the finishing end of second plasma advancing tube  1102 , frustoconical tube  1108  that becomes a deflection/oscillation tube connected to rectifying tube  1107 , and outlet tube  1109 . Frustoconical tube (deflection/oscillation tube)  1108  has its diameter increased toward the outlet tube  1109  side. Plasma outlet  1110  of outlet tube  1109  is connected to the plasma introduction port of plasma processing portion  101 . Outlet tube  1109  has a constant diameter. In the plasma transport tube concerning the present embodiment, the respective plasma advancing lengths L 1 -L 3  of first plasma advancing tube  1101 , second plasma advancing tube  1102 , and third plasma advancing tube  1103  are set to be same as each plasma advancing tube of  FIG. 7 . Also, at the position off the line of sight from plasma outlet  1110  of outlet tube  1109  to the plasma outlet  1105  side of first plasma advancing tube  1101 , second plasma advancing tube  1102  is placed geometrically in the same manner as  FIGS. 7 and 11 . That is to say, when the angle of elevation from the tube cross section bottom end of the plasma outlet  1110  side of outlet tube  1109  to the tube cross section top end of the plasma outlet  1106  side of second plasma advancing tube  1102  is defined as θ 0  as shown by arrow  1112 , the angle of elevation (θ) from the tube cross section top end of the plasma entrance port side of rectifying tube  1107  to the tube cross section bottom end of the plasma outlet  1105  side of first plasma advancing tube  1101  as shown by arrow  1111  satisfies θ≧θ 0  in the same manner as  FIG. 7 . By the same tube passage geometric placement as  FIGS. 7 and 11 , through avoiding the straightly advancing droplets led out from first plasma advancing tube  1101  directly intruding third plasma advancing tube  1103 , they are prevented from being exhausted from plasma outlet  1110  of third plasma advancing tube  1103 . 
     In the connecting section with third plasma advancing tube  1103  of the finishing end of second plasma advancing tube  1102  which has been inclinedly arranged, to prevent a decrease in the plasma progress efficiency to the third plasma advancing tube  1103  side through meandering and diffusion of the plasma flow, rectifying magnetic field coil  1114  is installed in rectifying tube  1107  connecting with second plasma advancing tube, so that a rectification magnetic field that rectifies while forcibly converging the plasma flow supplied from second plasma advancing tube  1102  to rectifying tube is generated in the tube. By this rectification magnetic field, the plasma flowing to second plasma advancing tube  1102  can be drawn in a converged manner at the third plasma advancing tube  1103  side, and a generation of plasma with high density and high purity becomes possible. 
       FIG. 19  is an explanatory diagram of a magnetic field for scanning formed inside frustoconical tube (deflection/oscillation tube)  1108  (shown in  FIG. 18 ) concerning the fifth embodiment. As shown in  FIGS. 18 and 19 , to scan the plasma stream like a CRT display by oscillating left-right and up-down the plasma stream converged and rectified by the effect of the rectification magnetic field, magnetic field coil  1113  for scanning is provided near frustoconical tube (deflection/oscillation tube)  1108  connected to rectifying tube  1107 . Magnetic field coil  1113  for scanning comprises a set of X-direction oscillating magnetic field generators  108   a,    108   a  and a set of Y-direction oscillating magnetic field generators  108   b,    108   b.    
     The relations of X-direction oscillating magnetic field B X (t) at time t by X-direction oscillating magnetic field generators  108   a,    108   a,  Y-direction oscillating magnetic field B Y (t) at time t by Y-direction oscillating magnetic field generators  108   b,    108   b,  and scanning magnetic field B R (t) at time t are shown. Scanning magnetic field B R (t) is a synthetic magnetic field of X-direction oscillating magnetic field B X (t) and Y-direction oscillating magnetic field B Y (t). To explain in detail, while the plasma stream is oscillated left-right by the X-direction oscillating magnetic field, the plasma stream is scanned up-down by Y-direction oscillating magnetic field, and by repeating this, a large-area plasma exposure to plasma processing portion  1  is made possible. When the cross section area of the plasma stream is smaller than the cross section area of the object to be treated placed inside plasma treatment chamber  1 , the plasma stream is scanned top-bottom and left-right, so that a plasma exposure is made possible on the entire surface of the object to be treated. A similar principle is used as, for example, when the electron beam of a CRT display oscillates left-right while moving up-down, and by repeating this movement, the entire surface of the display screen is made to emit light. In  FIG. 19 , magnetic field B R (t 1 ) for scanning is synthesized from oscillating magnetic fields B X (t 1 ) and B Y (t 1 ) at time t=t 1 , and while magnetic field B R (t 1 ) for scanning oscillates left-right, magnetic field B R (t 2 ) for scanning is formed at time t=t 2  by oscillating magnetic fields B X (t 2 ) and B Y (t 2 ), so that the plasma stream can be deflected and oscillated on almost the entire surface of the tube. 
     The present invention is not limited to the embodiments described above. Various modifications, design alterations, and others that do not involve a departure from the technical concept of the present invention are also included in the technical scope of the present invention. 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, a multiply divided anode wall type plasma generation apparatus can be provided that can improve the operation efficiency without decreasing the plasma generation efficiency by preventing an exfoliation of a large carbon flake. Also, according to a plasma processing apparatus concerning the present invention, an improvement of the operation efficiency is done by having installed a multiply divided anode wall type plasma generation apparatus, and at the same time, a high purification of the generated plasma can be realized by carrying out an elimination measure of neutral droplets and electrically charged droplets. Because of this, it becomes possible to form in the plasma a highly pure thin film whose defects and impurities on the surface of the solid material are markedly few, and to reform uniformly the surface characteristics of a solid without adding defects and impurities by irradiating the plasma, and a plasma processing apparatus can be provided for forming, for example, an abrasion- and corrosion-resistant reinforced film, a protective film, an optical thin film, and a transparent electroconductive film among others in high quality and precision.