Abstract:
A film-forming method of an osmium film includes disposing a metal plate in a chamber; introducing OsO 4  gas at a flow rate of 0.1 to 3 cc/min and an inert gas for maintaining discharge into the chamber while maintaining the pressure in the chamber to 13 to 40 Pa; and forming an osmium film on the surface of the metal plate by turning the gas in the chamber into plasma using radio frequency output power with the density of 0.25 to 2.0 W/cm 2 .

Description:
TECHNICAL FIELD 
     The present invention relates to a film-forming treatment jig for forming a thin film on a plate having a through hole of a micro diameter by a single plasma film-forming treatment, a plasma CVD (Chemical Vapor Deposition) apparatus using the film-forming treatment jig, a metal plate, and an osmium film forming method. 
     BACKGROUND ART 
       FIG. 8  is a cross-sectional view showing a conventional plasma CVD apparatus in outline.  FIG. 9  is a front view showing an aperture plate. The aperture plate  107  is a component for narrowing an electron beam in an electron microscope. The plasma CVD apparatus shown in  FIG. 8  is an apparatus for forming a metal film on the surface of the aperture plate  107 . 
     As shown in  FIG. 8 , the conventional plasma CVD apparatus has a chamber  101 , and, in the chamber  101 , a gas shower electrode  102  as an upper electrode of a parallel flat plate type and a lower electrode  103  are arranged. The gas shower electrode  102  is connected to a raw material gas supply source  104 . Moreover, the gas shower electrode  102  and the chamber  101  are connected to the ground potential. 
     On the lower electrode  103 , a substrate  106  is placed, and on the substrate  106 , the aperture plate  107  is attached. To the lower electrode  103 , a radio frequency power source (RF power source)  109  is connected via a matching box  108 . 
     The aperture plate  107  shown in  FIG. 9  is a plate-like member having a thickness of 10 to 500 μm, and has a first through hole (a through hole for the attachment)  107   a  with a diameter of around 2 mm. Moreover, for the aperture plate  107 , a plurality of second through holes (not shown) with a diameter of around 2 to 100 μm is arranged, wherein the second through hole is a hole for narrowing the electron beam in an electron microscope. The portions for which the formation of the metal film is necessary in the aperture plate  107  are a portion located near the second through hole on the front and back surfaces of the aperture plate, and the inside surface of the second through hole. 
     A method of forming the metal film on the aperture plate  107  using the above conventional plasma CVD apparatus is as follows. 
     On the substrate  106  such as a wafer, the aperture plate  107  is attached, and the substrate  106  is placed on the lower electrode  103  in the chamber  101 . Subsequently, a raw material gas is supplied to the gas shower electrode  102  from the raw material gas supply source  104 , and the raw material gas is ejected from the gas shower electrode  102  in a shower shape toward the lower electrode  103 . Then, by outputting a radio frequency wave from the RF power source  109  to the lower electrode  103  via the matching box  108 , a metal film is formed on the surface of the aperture plate  107  and the inside surface of the second through hole by a plasma CVD method. 
     After that, the substrate  106  is taken out of the chamber  101 , the aperture plate  107  is peeled off from the substrate  106  and attached on the substrate  106  so that the other surface (the back surface) of the aperture plate  107  is exposed, and the substrate  106  is placed on the lower electrode  103  in the chamber  101 . After that, by the same method as that for forming the metal film on the front surface of the aperture plate  107 , the metal film is formed on the back surface of the aperture plate  107  and the inside surface of the second through hole. 
     SUMMARY OF THE INVENTION 
     In the above-mentioned conventional plasma CVD apparatus, in the case of a plate having a second through hole with a micro diameter such as an aperture plate, in order to form a thin film on the inside surface of the second through hole, and on a portion located near the second through hole on the front and back surfaces of the plate, as described above, a double film-forming treatment must be performed. Consequently, there was such a problem that the cost of the film-forming treatment for the plate becomes high. Moreover, when the double film-forming treatment is performed, an interface is necessarily formed between the first metal film formed by the first round of film-forming treatment and the second metal film formed by the second round of film-forming treatment, and, as the result, there occasionally arises such a problem that the peeling occurs at the interface of the first metal film and the second metal film. 
     On the other hand, there is such a proposal as forming an osmium film being the metal film on the front and back surfaces of the aperture plate and the inside surface of the second through hole. The osmium film has high resistance properties against an electron beam, and, therefore, it is expected to exert high performance as compared with other metal films. 
     In the above-described conventional plasma CVD apparatus of a parallel plate type, however, since plasma diffuses easily, heavy OsO 4  gas being a raw material gas for forming the osmium film hardly enters the second through hole of a micro diameter, and, as the result, the osmium film was not formed on the inside surface of the second through hole with good uniformity. In other words, even when the osmium film is formed on the inside surface of the second through hole by the conventional plasma CVD apparatus, the osmium film had low uniformity not to give, consequently, a high performance. 
     The present invention was achieved in view of the above circumstances, and an object thereof is to provide a film-forming treatment jig for forming a thin film on a plate having a through hole of a micro diameter by a single plasma film-forming treatment, and a plasma CVD apparatus using the film-forming treatment jig. 
     Another object of the present invention is to provide a metal plate having an osmium film formed on the inside surface of a through hole of a micro diameter with good uniformity. 
     Another object of the present invention is to provide a film-forming method of an osmium film for forming an osmium film on the surface of a metal member. 
     In order to solve the above problems, the film-forming treatment jig according to the present invention is a film-forming treatment jig including: a holding member for holding a plate, by clamping the plate having a through hole, in a state of exposing the through hole and the front and back surfaces of the plate; and an electrode member having the holding member attached thereon, wherein the electrode member is electrically connected to an electrode to which plasma electric power of a plasma CVD apparatus is applied. 
     According to the film-forming treatment jig, since it has a holding member for holding a plate, by clamping the plate having a through hole, in a state of exposing the through hole and the front and back surfaces of the plate, the formation of a thin film on the plate becomes possible by a single plasma film-forming treatment. Herewith, since the electrode member having the holding member attached thereon is one electrically connected to an electrode to which plasma electric power of a plasma CVD apparatus is applied, it is possible to make the electrode member function as a part of the electrode. 
     Moreover, in the film-forming treatment jig according to the present invention, the electrode member preferably has a flange used to be placed on a transfer arm. 
     The plasma CVD apparatus according to the present invention is a plasma CVD apparatus including: 
     a chamber, 
     a first electrode disposed in the chamber, 
     a second electrode disposed in the chamber, and disposed so as to face the first electrode, 
     a power source electrically connected to at least one of the first electrode and the second electrode, for applying plasma electric power, 
     a raw material gas introduction mechanism for introducing a raw material gas into the chamber, and 
     a film-forming treatment jig including: a holding member for holding a plate, by clamping the plate having a through hole, in a state of exposing the through hole and the front and back surfaces of the plate; and an electrode member having the holding member attached thereon, wherein 
     the electrode member functions as a part of the second electrode when a thin film is formed on the front and back surfaces of the plate held by the holding member and the inside surface of the through hole by a plasma CVD method, by electrically connecting the electrode member onto the second electrode and placing the plate held by the holding member between the first electrode and the second electrode. 
     Moreover, in the plasma CVD apparatus according to the present invention, it is also possible that the electrode member has a flange, and the apparatus comprises a transfer mechanism for transferring the film-forming treatment jig into the chamber by placing the flange on a transfer arm. 
     Moreover, it is preferable that the plasma CVD apparatus according to the present invention further includes a plasma wall arranged around the plate arranged in the chamber and placed between the first electrode and the second electrode, and that the plasma wall is connected to a float potential. This makes it possible to concentrate the flow of the raw material gas introduced into the chamber around the plate by the plasma wall, and also to confine the plasma around the plate by the plasma wall to raise the plasma density. 
     Moreover, in the plasma CVD apparatus according to the present invention, it is preferable to introduce the raw material gas by the raw material gas introduction mechanism in a direction approximately parallel to the surface of the plate placed between the first electrode and the second electrode. 
     The plasma CVD apparatus according to the present invention is a plasma CVD apparatus including: 
     a chamber; 
     an upper electrode disposed in the chamber; 
     a lower electrode disposed in the chamber, and disposed so as to face the upper electrode, on the lower side; 
     a power source electrically connected to at least one of the upper electrode and the lower electrode to apply plasma electric power; 
     a raw material gas introduction mechanism for introducing a raw material gas into the chamber, and for causing the raw material gas to flow from the upper electrode side toward the lower electrode side; 
     a film-forming treatment jig including: a holding member for holding a plate, by clamping the plate having a through hole, in a state of exposing the through hole and the front and back surfaces of the plate; an electrode member having the holding member attached thereon; and a flange provided to the electrode member; 
     a transfer mechanism for transferring the film-forming treatment jig into the chamber by placing the flange on a transfer arm, wherein 
     the electrode member functions as a part of the second electrode when a thin film is formed on the front and back surfaces of the plate held by the holding member and the inside surface of the through hole by a plasma CVD method, by electrically connecting the electrode member onto the lower electrode, and placing the plate held by the holding member between the upper electrode and the lower electrode and placing the plate so that the surface thereof becomes approximately parallel to the direction vertical to the upper surface of the lower electrode. 
     Moreover, in the plasma CVD apparatus according to the present invention, it is preferable that the plate is an aperture plate, that the through hole has a diameter of 100 μm or less, and that the thin film is an osmium film. 
     Furthermore, in the plasma CVD apparatus according to the present invention, the plasma electric power is preferably radio frequency power. 
     The metal plate according to the present invention is a metal plate including a plate having a through hole with a diameter of 100 μm or less, and an osmium film formed by a single film-forming treatment by a plasma CVD apparatus, on the inside surface of the through hole and on the front and back surfaces located near the through hole of the plate, wherein 
     the plasma CVD apparatus comprises: 
     a chamber, 
     an upper electrode disposed in the chamber; 
     a lower electrode disposed in the chamber, and disposed so as to face the upper electrode, on the lower side; 
     a power source electrically connected to at least one of the upper electrode and the lower electrode to apply plasma electric power; 
     a holding member electrically connected to the lower electrode, for holding the plate in a state of exposing the through hole and the front and back surfaces of the plate by clamping the plate to place the plate between the upper electrode and the lower electrode; 
     a plasma wall arranged in the chamber, placed around the plate, and connected to a float potential; and 
     a raw material gas introduction mechanism for introducing a raw material gas into the chamber, for causing the raw material gas to flow from the upper electrode side toward the lower electrode side, and for causing the raw material gas to flow in a direction along the front and back surfaces of the plate. 
     According to the metal plate, the osmium film can be formed on the inside surface of the through hole of a micro diameter with better uniformity as compared with conventional techniques, and, since the osmium film is formed by a single film-forming treatment, the interface as is the case for a film formed by multiple treatments does not generate in the osmium film. 
     In the metal plate according to the present invention, the thickness of the osmium film is preferably from 10 nm to 50 nm, inclusive. 
     In the metal plate according to the present invention, the plasma electric power is preferably radio frequency power. 
     In the metal plate according to the present invention, the metal plate may also be an aperture plate. 
     The film-forming method of an osmium film according to the present invention is characterized by including the steps of: 
     disposing a metal member in a chamber; 
     introducing OsO 4  gas at a flow rate of 0.1 to 3 cc/min and an inert gas for maintaining discharge into the chamber while maintaining the pressure in the chamber to 13 to 40 Pa; and 
     forming an osmium film on the surface of the metal member by turning the gas in the chamber into plasma using radio frequency output power with the density of 0.25 to 2.0 W/cm 2 . 
     Meanwhile, into the chamber, H 2  gas at a flow rate of 5 to 15 cc/min may be introduced, and the metal member may be heated to a temperature of 200 to 300° C. to form the film. The metal member may also be a metal plate. The inert gas may also be He or Ar. 
     According to the film-forming method of an osmium film, by using RF discharge by radio frequency output power, and defining each range of the radio frequency output power density, and OsO 4  gas and pressure, the remaining of oxygen contained in the raw material gas in the osmium film formed on the metal member can be suppressed. The osmium film has such properties as resistant to electron beams. 
     In contrast, when DC discharge is used to form an osmium film on the surface of the metal member, in the osmium film, oxygen in the raw material gas easily remains and suppressing the remaining of the oxygen is difficult. Osmium films in which the oxygen remains in this manner have such defect as not resistant to electron beams. 
     The reason why the above-described difference between the RF discharge and the DC discharge is generated is considered that the case of the RF discharge gives a stable discharge to enable the suppression of the remaining of the oxygen contained in the raw material gas, but that the case of the DC discharge gives an unstable discharge not to allow the suppression of the remaining of the oxygen contained in the raw material gas. 
     As described above, according to the present invention, it is possible to provide a film-forming treatment jig for forming a thin film for a plate having a through hole of a micro diameter by a single plasma film-forming treatment, and a plasma CVD apparatus using the film-forming treatment jig. 
     Moreover, according to another present invention, it is possible to provide an aperture plate in which an osmium film is formed on the inside surface of the through hole of a micro diameter with good uniformity. 
     Furthermore, according to another present invention, it is possible to provide a film-forming method of an osmium film for forming an osmium film on the surface of a metal member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view showing the whole constitution of a plasma CVD apparatus according to an Example according to the present invention. 
         FIG. 2  is a cross-sectional view along the  2   a - 2   a  line shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view schematically showing the film-forming chamber, the plasma power source and the raw material gas supply mechanism shown in  FIG. 2 . 
         FIG. 4(A)  is a side view showing a film-forming treatment jig holding an aperture plate, and  FIG. 4(B)  is a top view of the film-forming treatment jig shown in  FIG. 4(A) . 
         FIG. 5(A)  is a drawing showing the situation when the film-forming treatment jig is transferred, and a plan view showing the state in which the film-forming treatment jig is placed on the transfer arm, and  FIG. 5(B)  is a side view showing the film-forming treatment jig and the transfer arm shown in  FIG. 5(A) . 
         FIG. 6  is a plan view showing a modified example of the film-forming treatment jig holding the aperture plate. 
         FIG. 7  is a cross-sectional view obtained by cutting the vicinity of the through hole of a micro diameter of the aperture plate for which an osmium film is formed by an experiment. 
         FIG. 8  is a cross-sectional view showing a conventional plasma CVD apparatus in outline. 
         FIG. 9  is a plan view showing an aperture plate. 
     
    
    
     DESCRIPTION OF REFERENCE NUMERALS AND SYMBOLS 
     
         
           1 : cleaning chamber,  2 : film-forming chamber,  3 : first transfer mechanism,  4 : second transfer mechanism,  5 : transfer chamber,  6 : first gate,  7 : second gate,  8 : film-forming treatment jig,  9 : cover,  10 : placement table,  11 : vertical movement mechanism,  11   a : placement portion,  11   b : movement mechanism,  12 : outer chamber,  13 : inner chamber,  14 : gas shower electrode,  15  to  22 : pipe,  23  to  26 : bulb,  27 ,  28 : mass flow controller (MFC),  29 : hydrogen gas supply source,  30 : OsO 4  gas supply source,  31 : heater,  32 : lower electrode,  33 : matching box,  34 : radio frequency power source (RF power source),  35 : vertical movement mechanism,  36 : arrow,  37 : plasma wall,  37   a : cylindrical rectification member,  37   b : ring-shaped rectification member,  37   c : cylindrical rectification member,  38 : film-forming position,  39 : holding member,  49 : flange member,  49   a : columnar member,  49   b : flange,  52  to  55 : positioning portion,  60 : float potential,  101 : chamber,  102 : gas shower electrode,  103 : lower electrode,  104 : raw material gas supply source,  106 : substrate,  107 : aperture plate,  107   a : first through hole,  107   b : through hole of a micro diameter (second through hole),  108 : matching box,  109 : radio frequency power source (RF power source),  110 : osmium film 
       
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, Examples of the present invention will be described with reference to the drawings. 
       FIG. 1  is a plan view showing the whole constitution of a plasma CVD apparatus by an Example according to the present invention.  FIG. 2  is a cross-sectional view along the  2   a - 2   a  line shown in  FIG. 1 .  FIG. 3  is a cross-sectional view schematically showing the film-forming chamber, the plasma power source and the raw material gas supply mechanism shown in  FIG. 2 . 
     As shown in  FIGS. 1 and 2 , the plasma CVD apparatus has a cleaning chamber  1  and a film-forming chamber  2 . The cleaning chamber  1  is connected to a transfer chamber  5  via a first gate  6 , and the transfer chamber  5  is connected to a first transfer mechanism  3 . When a film-forming treatment jig  8  holding an aperture plate  107  is inserted into the transfer chamber  5 , the first transfer mechanism  3  is one that transfers the film-forming treatment jig  8  in the transfer chamber  5  toward the lower side of the cleaning chamber  1  through the opened first gate  6 . Moreover, the film-forming chamber  2  is connected to the transfer chamber  5  via a second gate  7 , and the transfer chamber  5  is connected to a second transfer mechanism  4 . The second transfer mechanism  4  is one for transferring the film-forming treatment jig  8  in the transfer chamber  5  toward the lower side of the film-forming chamber  2  through the opened second gate  7 . 
     The transfer chamber  5 , the film-forming chamber  2  and the periphery thereof will be described in detail with reference to  FIGS. 2 and 3 . 
     As shown in  FIG. 2 , the transfer chamber  5  has a freely openable and closable cover  9 . In the transfer chamber  5 , a placement table  10  for placing the film-forming treatment jig  8 , and a vertical movement mechanism  11  for vertically moving the film-forming treatment jig  8  placed on the placement table  10  are arranged. The vertical movement mechanism  11  has a placement portion  11   a  for placing the film-forming treatment jig  8 , and a movement mechanism  11   b  for vertically moving the placement portion  11   a . Moreover, to the transfer chamber  5 , an evacuation mechanism such as a vacuum pump is connected, and is constituted to evacuate the inside of the transfer chamber  5  by the evacuation mechanism. Meanwhile, the insertion of the film-forming treatment jig  8  holding the aperture plate  107  into the transfer chamber  5  is performed by opening the cover  9  in a state where the second gate  7  is closed, placing the film-forming treatment jig  8  holding the aperture plate  107  on the placement table  10 , and, after that, closing the cover  9 . 
     As shown in  FIG. 2 , the film-forming chamber  2  has an outer chamber  12 , and the outer chamber  12  is connected to the transfer chamber  5  via the freely openable and closable second gate  7 . Moreover, to the outer chamber  12 , such an evacuation mechanism as a vacuum pump is connected, and it is constituted so that the inside of the outer chamber  12  can be evacuated by the evacuation mechanism. 
     As shown in  FIGS. 2 and 3 , inside the outer chamber  12 , an inner chamber  13  is disposed. At the upper portion of the inner chamber  13 , a gas shower electrode  14  as an upper electrode is arranged. To the gas shower electrode  14 , a first gas supply mechanism for supplying hydrogen gas and a second gas supply mechanism for supplying OsO 4  gas are connected. 
     The first gas supply mechanism has a hydrogen gas supply source  29 , and, to the hydrogen gas supply source  29 , one end of a pipe  18  is connected. To the other end of the pipe  18 , one end of a bulb  24  is connected, and, to the other end of the bulb  24 , one end of a pipe  17  is connected. To the other end of the pipe  17 , one end of a mass flow controller (MFC)  27  is connected, and, to the other end of the mass flow controller  27 , one end of a pipe  16  is connected. To the other end of the pipe  16 , one end of a bulb  23  is connected, and, to the other end of the bulb  23 , one end of a pipe  15  is connected. To the other end of the pipe  15 , the gas shower electrode  14  is connected. 
     The second gas supply mechanism has an OsO 4  gas supply source  30 , and, to the OsO 4  gas supply source  30 , one end of a pipe  22  is connected. To the other end of the pipe  22 , one end of a bulb  26  is connected, and, to the other end of the bulb  26 , one end of a pipe  21  is connected. To the other end of the pipe  21 , one end of a mass flow controller (MFC)  28  is connected, and, to the other end of the mass flow controller  28 , one end of a pipe  20  is connected. To the other end of the pipe  20 , one end of a bulb  25  is connected, and, to the other end of the bulb  25 , one end of a pipe  19  is connected. To the other end of the pipe  19 , the gas shower electrode  14  is connected. The OsO 4  gas supply source  30  has a heater  31 , and it is constituted so that the heater  31  heats and sublimates solid OsO 4  to generate OsO 4  gas. It is also constituted so that each of pipes  19  to  21 , bulbs  25  and  26 , and the mass flow controller  28  is heated by a heater (not shown) to around 80° C. This makes it possible to introduce the OsO 4  gas generated by the OsO 4  gas supply source  30  into the gas shower electrode  14  without the solidification. 
     The gas shower electrode  14 , the inner chamber  13  and the outer chamber  12  are connected to the ground potential. 
     On the lower side of the inner chamber  13 , a lower electrode  32  is arranged, and, to the lower electrode  32 , a radio frequency power source (RF power source)  34  is connected via a matching box  33 . The radio frequency power source may use a frequency in the range of 100 kHz to 27 MHz. 
     Further, as shown in  FIG. 2 , the apparatus has a vertical movement mechanism  35  for vertically moving the lower electrode  32  between the lower portion of the outer chamber  12  and the lower portion of the inner chamber  13 . In such a state that the vertical movement mechanism  35  has moved the lower electrode  32  to the lower side of the outer chamber  12 , a transfer arm  4   a  of the second transfer mechanism  4  holds the film-forming treatment jig  8  in the transfer chamber  5 , the transfer arm  4   a  moves the film-forming treatment jig  8  through the opened second gate  7  to the lower side of the outer chamber  12 , and the film-forming treatment jig  8  is placed on the lower electrode  32  to be attached or engaged or electrically connected thereto. Then, the transfer arm  4   a  is returned into the transfer chamber  5 , and the second gate  7  is closed. The vertical movement mechanism  35  raises the lower electrode  32  having the film-forming treatment jig  8  attached thereon to move the lower electrode  32  from the lower side of the outer chamber  12  to the lower portion of the inner chamber  13 , and, thereby, the film-forming treatment jig  8  electrically connected to the lower electrode  32  is disposed in the inner chamber  13 . As described above, the aperture plate  107  is arranged between the gas shower electrode  14  and the lower electrode  32 , and is placed approximately parallel to the direction (shown by an arrow  36 ) in which the raw material gas is ejected in a shower shape from the gas shower electrode  14 . The position is a film-forming position  38  when the aperture plate  107  is film-formed. 
     The film-forming treatment jig  8  is formed, for example, from SUS, and functions also as a part of the lower electrode. Consequently, when radio frequency power is applied to the lower electrode  32  from the RF power source  34  through the matching box  33 , the radio frequency power is applied to the aperture plate  107  through the film-forming treatment jig  8 . Meanwhile, the specific structure of the film-forming treatment jig  8 , the holding method for holding the aperture plate  107  and the like will be described later. 
     As shown in  FIG. 3 , around the aperture plate  107  in the inner chamber  13 , a plasma wall  37  made of ceramics or quartz or glass is arranged. The plasma wall  37  has a role of rectifying the flow of the raw material gas introduced from the gas shower electrode  14  so as to concentrate around the aperture plate  107 , and a role of confining the plasma around the aperture plate  107  to raise the plasma density. Only when the plasma wall  37  can fulfill the role, the shape and the material thereof are changeable, and, in the Example, the shape as shown in  FIG. 3  is adopted. 
     That is, the plasma wall  37  has a cylindrical rectification member  37   a  and a ring-shaped rectification member  37   b  for controlling the flow of the raw material gas, and a cylindrical rectification member  37   c  arranged outside the cylindrical rectification member  37   a  to suppress the discharge between the inner chamber wall and the outer chamber wall. Each upper portion of the cylindrical rectification members  37   a  and  37   c  is connected by the ring-shaped rectification member  37   b . And, the plasma wall  37  is connected to a float potential  60 . By the ring-shaped rectification member  37   b  and the cylindrical rectification member  37   a , it is possible to concentrate the raw material gas from the gas shower electrode  14  around the aperture plate  107 , and, as the result, to improve the use efficiency of the raw material gas. Moreover, by the cylindrical rectification member  37   c , it is possible to suppress the diffusion of the plasma and to raise the plasma density, and to stabilize the discharge around the aperture plate  107 . 
     Next, the specific structure of the film-forming treatment jig  8 , the method of holding the aperture plate  107  thereto and the like will be described with reference to  FIGS. 4 and 5 . 
       FIG. 4(A)  is a front view showing the film-forming treatment jig holding the aperture plate, and  FIG. 4(B)  is a plan view showing the film-forming treatment jig shown in  FIG. 4(A) .  FIG. 5(A)  is a drawing showing the situation when the film-forming treatment jig is transferred and a plan view showing the state where the film-forming treatment jig is placed on the transfer arm, and  FIG. 5(B)  is a front view showing the film-forming treatment jig and the transfer arm shown in  FIG. 5(A) . 
     As shown in  FIGS. 4(A) and 4(B) , the holding member  39  has a cylindrical shape. The holding member  39  holds four aperture plates  107  in a state of clamping the flange. The holding state is a state wherein the second through hole (the through hole of a micro diameter described in  FIG. 9 ), and the front and back surfaces of the aperture plate  107  are exposed. 
     The holding member  39  is attached to a flange member  49 . This makes it possible to hold each of the four aperture plates  107  held by the holding member  39  in a state of erecting each of them in the vertical direction relative to the upper surface of the flange member  49 . The flange member  49  has, as shown in  FIG. 4(A) , a columnar member  49   a  and a flange  49   b  of a convex shape provided around the upper portion of the columnar member  49   a . The flange  49   b  is one to be placed on the transfer arm  4   a  as shown in  FIGS. 5(A) and 5(B) . That is, by locating the transfer arm  4   a  around the columnar member  49   a , and placing the flange  49   b  on the transfer arm  4   a  while positioning the flange  49   b  by the positioning portions  52  to  55 , the state is set so that the film-forming treatment jig  8  may be transferred by the transfer arm  4   a . Meanwhile, when the film-forming treatment jig  8  is connected to the lower electrode  32  shown in  FIG. 3 , the flange member  49  becomes an electrode member and functions as a part of the lower electrode. 
     Next, the method of forming an osmium film for the aperture plate using the above-described plasma CVD apparatus will be described. 
     Firstly, as shown in  FIGS. 4(A) and 4(B) , four aperture plates  107  are held by the holding member  39  of the film-forming treatment jig  8 , and, as shown in  FIGS. 2  and  FIGS. 5(A) and 5(B) , the movement mechanism  11   b  is raised to place the film-forming treatment jig  8  placed on the placement table  10  on the placement portion  11   a . Then, the movement mechanism  11   b  is further raised to move the transfer arm  4   a  to the lower side of the film-forming treatment jig  8  placed on the placement portion  11   a . After that, by lowering the movement mechanism  11   b  to lower the film-forming treatment jig  8  along with the placement portion  11   a , the flange  49   b  of the film-forming treatment jig  8  is placed on the transfer arm  4   a . As described above, the film-forming treatment jig  8  is placed on the transfer arm  4   a , to set such a state that the film-forming treatment jig  8  may be transferred by the transfer arm  4   a . After that, the film-forming treatment jig  8  is transferred from the transfer chamber  5  to the cleaning chamber  1  by the first transfer mechanism  3 , and the aperture plate  107  is subjected to a cleaning treatment. After that, the film-forming treatment jig  8  is transferred from the cleaning chamber  1  to the transfer chamber  5  by the first transfer mechanism  3 . 
     Subsequently, as shown in  FIG. 2 , the state is set so that the film-forming treatment jig  8  may be transferred by the transfer arm  4   a , the film-forming treatment jig  8  is transferred by the second transfer mechanism  4  from the transfer chamber  5  to the film-forming chamber  2 , and the film-forming treatment jig  8  is positioned at the film-forming position  38 . 
     Next, as shown in  FIG. 3 , the first gas supply mechanism and the second gas supply mechanism supply hydrogen gas and OsO 4  gas to the gas shower electrode  14 , and the hydrogen gas and the OsO 4  gas are supplied from the gas shower electrode  14  toward the aperture plate  107 . On this occasion, the reason why the raw material gas is flown from top to bottom (in the gravity direction) as the arrow  36  is that the OsO 4  gas has a large molecular weight. Conversely, in the case of a raw material gas having a small molecular weight, if the gas may be supplied to the front and back surfaces of the aperture plate with good uniformity, it is not necessarily flown from top to bottom, and the direction of flowing the raw material gas may appropriately be changed. 
     After that, by supplying radio frequency power to the lower electrode  32  by the RF power source  34  to apply the radio frequency power to the aperture plate  107 , an osmium film having a thickness of 10 nm or more is formed on the front and back surfaces of the aperture plate  107  and the inside surface of the second through hole (the through hole of a micro diameter described in  FIG. 9 ) by a single film-forming treatment with good uniformity by a plasma CVD method. The chemical reaction on this occasion is as follows, wherein, as shown in formulae (1) and (2) below, the gas is ionized in the plasma and the film-forming reaction in the formula (3) below occurs on the aperture plate.
 
H 2 +2 e   − →2H + +4 e   −   (1)
 
OsO 4   +e   − →OsO 4   + +2 e   −   (2)
 
OsO 4   + +8H + +9 e   − →Os↓+4H 2 O↑  (3)
 
     The reason why the osmium film is to be formed for the aperture plate  107  is that osmium film has higher resistance properties against an electron beam as compared with other metal films to actualize long life, and enables the focusing properties of an electron beam to rise. 
     According to the above Example, since the film-forming treatment jig  8  has the aforementioned structure, as shown in  FIG. 2 , it is possible to transfer the film-forming treatment jig  8  by the transfer arm  4   a , and to attach or fit the transferred film-forming treatment jig  8  on or in the lower electrode  32 . Then, since the film-forming treatment jig  8  attached to the lower electrode  32  functions also as a lower electrode, as shown in  FIG. 3 , by supplying radio frequency power to the lower electrode  32 , the radio frequency power can be applied to the aperture plate  107  through the film-forming treatment jig  8 . Further, the holding member  39  of the film-forming treatment jig  8  can hold the aperture plate  107  in a state of exposing the front and back surfaces thereof. Consequently, by performing a single film-forming treatment with the plasma CVD apparatus, it is possible to form an osmium film, for a plate having a through hole of a micro diameter such as the aperture plate  107  (one explained as the second through hole in  FIG. 9 ), on the inside surface of the through hole and the portion located near the through hole on the front and back surfaces of the plate. Accordingly, the treatment time of the film-forming treatment for the plate can be reduced, and, as the result, the cost of the film-forming treatment can be lowered. 
     Additionally, in the Example, since the plasma wall  37  connected to the float potential  60  is arranged around the aperture plate  107 , it is possible to concentrate the raw material gas from the gas shower electrode  14  around the aperture plate  107 , and to suppress the diffusion of the plasma and to concentrate the plasma for the aperture plate  107  to raise the plasma density. Consequently, even when a raw material gas for the film-forming that has a large molecular weight and is heavy such as OsO 4  gas is used, the osmium film can be formed on the inside surface of the through hole of a micro diameter with good uniformity. 
     Meanwhile, the present invention is not limited to the above Example, but may be practiced in variously changed modes within the scope not deviating from the gist of the present invention. For example, as shown in  FIG. 6 , the holding member  39  of the film-forming treatment jig may be so constituted as holding six aperture plates  107 . 
     Further, in the above Example, the lower electrode  32  is connected to the radio frequency power source  34 , and the upper electrode  14  is connected to the ground potential, but the upper electrode  14  may be connected to the radio frequency power source and the lower electrode  32  may be connected to the ground potential, or the upper electrode  14  may be connected to a first radio frequency power source and the lower electrode  32  may be connected to a second radio frequency power source. Furthermore, the radio frequency power source may be changed to another plasma power source. Examples of other plasma power sources include a power source for micro wave, a power source for DC discharge, and each of the pulse-modulated radio frequency power source, power source for micro wave and power source for DC discharge. 
     In the above Example, electrodes are arranged vertically such as the upper electrode  14  and the lower electrode  32 , but the arrangement is not limited to this, and electrodes may be arranged from side to side. 
     Next, there are explained conditions and results of the experiment of forming an osmium film for the aperture plate having a through hole of a micro diameter using the plasma CVD apparatus according to the above Example. 
     (Experiment Conditions) 
     
         
         Radio frequency output power density: 0.25 to 2.0 W/cm 2    
         Frequency of Radio frequency wave: 13.56 MHz 
         OsO 4  gas flow rate: 0.1 to 3 cc/min 
         H 2  gas flow rate: 5 to 15 cc/min 
         Ar gas flow rate: 5 to 15 cc/min 
         Pressure: 13 to 40 Pa 
         Film-forming time: 10 to 50 seconds 
         Heating temperature: 200 to 300° C. 
         Os film thickness: 10 to 50 nm
 
(Experiment Results)
 
       
    
       FIG. 7  schematically shows the aperture plate  107  for which an osmium film  110  is formed by the experiment, and is a cross-sectional view of the aperture plate cut in the vicinity of the through hole (second through hole)  107   b  of micro diameter (specifically 2 to 100 μm). As shown in FIG.  7 , it was confirmed that, since the osmium film  110  was formed by a single film-forming treatment, an interface is not formed unlike the case of thin films formed by such conventional technique as the double film-forming treatment, and that the osmium film  110  can be formed on the inside surface of the through hole  107   b  of a micro diameter with good uniformity. As the result, the peeling of the osmium film  110  is suppressed, and the osmium film  110 , that gives very good focusing properties of electron beams and has high resistance properties for electron beams to give long life, was formed for the through hole  107   b  of a micro diameter.