Patent Publication Number: US-2002000197-A1

Title: Vacuum processing apparatus and multi-chamber vacuum processing apparatus

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a vacuum apparatus, and particularly to an apparatus for introducing gas into vacuum atmosphere wherein an object is processed in vacuum.  
       [0003] 2. Detailed Description of the Related Art  
       [0004] A vacuum processing apparatus of the prior art will be described below taking a CVD apparatus as an example.  
       [0005] Reference numeral  101  in FIG. 16 denotes the vacuum processing apparatus of the prior art. The vacuum processing apparatus  101  has a vacuum vessel  110 .  
       [0006] The vacuum vessel  110  has an inlet port  117  provided in the ceiling thereof. The inlet port  117  is connected to a raw material gas generation system  135  via a feed tube  131 .  
       [0007] A shower plate  112  is disposed at a position lower than the inlet port  117  in the vacuum vessel  110 . There is a clearance between the shower plate  112  and the ceiling of the vacuum vessel  110 , the clearance constituting a gas storing chamber  118 .  
       [0008] A space between the shower plate  112  and the bottom of the vacuum vessel  110  constitutes a reaction chamber  114 , and a substrate stage  113  is provided on the bottom of the vacuum vessel  110  at the lowest position in the reaction chamber  114 .  
       [0009] An exhaust port  128  is provided in the side wall of the reaction chamber  114  at a position lower than the substrate stage  113 . The exhaust port  128  is connected to a vacuum pump  124  via an exhaust tube pipe  122 . The exhaust tube  122  is fitted with a pressure regulating valve  123  installed therein at a position between the vacuum pump  124  and the exhaust port  128 .  
       [0010] In order to form a thin film on a substrate surface in the vacuum processing apparatus  101 , first the pressure regulating valve  123  is fully opened to pump the inside of the vacuum vessel  110  to be vacuum, and the substrate is carried into the reaction chamber  114 . When carrying in the substrate, the atmosphere in the vacuum vessel  110  is maintained vacuum.  
       [0011] Reference numeral  115  in FIG. 16 denotes the substrate being carried into the reaction chamber  114  and placed on the substrate stage  113 . The substrate  115  is heated to a predetermined temperature by a heater installed in the substrate stage  113 .  
       [0012] Then the extent of opening the pressure regulating valve  123  is decreased, and a raw material gas for depositing of the thin film is introduced from the gas introduction system  130  into the storing chamber  118 . The raw material gas which has filled the gas storing chamber  118  passes small holes of the shower plate  112  and diffuses in the reaction chamber  114 . When the raw material gas reaches the surface of the substrate  115 , chemical reaction takes place on the substrate  115  surface so that a thin film grows thereon.  
       [0013] Arrow  119  indicates the flow of the raw material gas before reaction and the flow of the waste gas after reaction. The raw material gas which is introduced through the small holes of the shower plate  112  into the reaction chamber  114  is, upon impinging on the surface of the substrate  115 , directed toward the outside of the substrate  115  to pass the clearance between a side face of the substrate stage  113  and the wall surface of the vacuum vessel  110 , thereby to reach the exhaust port  128 .  
       [0014] When the thin film having the predetermined thickness has been deposited on the surface of the substrate  115 , introduction of the raw material gas is stopped and the pressure regulating valve  123  is fully opened thereby to remove the raw material gas remaining in the reaction chamber  114  and in the gas storing chamber  118  by vacuum pumping.  
       [0015] However, since preference is placed on the pressure controllability during growth of the thin film in the vacuum processing apparatus  101  of such a constitution as described above, the pressure regulating valve  123  used is of such a type that is capable of precisely controlling the extent of opening.  
       [0016] Also the residual gas in the reaction chamber  114  flows between the substrate stage  113  and the wall surface of the vacuum vessel  110  when evacuated, and therefore conductance of evacuation thereof is low and the gas is likely to remain in the reaction chamber  114 .  
       [0017] When the substrate  115  is carried out with the gas remaining in the vacuum vessel  110 , the residual gas enters the transfer chamber to which the substrate is moved. The residual gas further enters the other units of the vacuum processing apparatus via the transfer chamber.  
       [0018] When a thin film is deposited by using an organometal gas in the MOCVD process, in particular, the raw material gas which has entered the transfer chamber adsorbs onto the wall surface thereof since the wall of the transfer chamber is cold. Since the raw material gas adsorbing onto the wall surface is not re-evaporated and the adsorbed raw material gas on the wall surface is emitted by degrees for a long, it degrades the degree of vacuum in the transfer chamber, making a cause of contamination.  
       [0019] The vacuum processing apparatus wherein an object is processed in vacuum by using a gas, as described above, is required to provide vacuum ambient pressure to be high during vacuum processing and decrease the pressure as low as possible when evacuating the remaining gas.  
       SUMMARY OF THE INVENTION  
       [0020] The present invention has been completed to solve the problems described above, and an object thereof is to provide a vacuum processing apparatus capable of increasing the speed of evacuating the residual gas.  
       [0021] In order to solve the problems described above, the present invention provides a vacuum processing apparatus including a vacuum vessel, a substrate stage disposed in the vacuum vessel, a stage moving mechanism for moving the substrate within the vacuum vessel, a vacuum pumping system for evacuating the inside of the vacuum vessel, and a gas introduction system for introducing gas into the vacuum vessel. The vacuum vessel is divided into a reaction chamber and an assistance chamber which communicate with each other, while the conductance of evacuation when the substrate stage with a substrate placed thereon is positioned in the reaction chamber is lower than the conductance of evacuation when the substrate stage is positioned in the assistance chamber.  
       [0022] The vacuum processing apparatus of the present invention may also have such a constitution as a ring-shaped contact member is provided on the inner wall surface of the vacuum vessel located between the reaction chamber and the assistance chamber so that, when the substrate stage is moved toward the reaction chamber, the substrate placed on the surface of the substrate stage is exposed to the inside of the reaction chamber through a central position of the contact member and, at the same time, a contact portion of the substrate stage and the contact member are brought into close contact with each other.  
       [0023] The vacuum processing apparatus of the present invention may also have such a constitution as a small hole is provided in the contact member so that, when the contact portion of the substrate stage and the contact member are brought into close contact with each other, the reaction chamber and the assistance chamber communicate with each other via the small hole.  
       [0024] In the vacuum processing apparatus of the present invention, the gas introduction system may be connected to the reaction chamber.  
       [0025] In the vacuum processing apparatus of the present invention, the gas introduction system may be constituted so as to introduce the gas to the reaction chamber from the top thereof.  
       [0026] The vacuum processing apparatus of the present invention may also have such a constitution as the gas introduction system is provided with a gas generation system which generates a raw material gas including an organometal compound, while the raw material gas is introduced into the reaction chamber.  
       [0027] In the vacuum processing apparatus of the present invention, the assistance chamber may be disposed below the reaction chamber.  
       [0028] The vacuum processing apparatus of the present invention may also have such a constitution as the vacuum pumping system is connected to the assistance chamber, so that the gas introduced into the reaction chamber is evacuated through the assistance chamber by vacuum pumping.  
       [0029] The vacuum processing apparatus of the present invention may also have such a constitution as a substrate loading/unloading port is provided in the wall of the assistance chamber, so that the substrate can be placed on the substrate stage via the substrate loading/unloading port while the substrate stage is positioned in the assistance chamber.  
       [0030] The vacuum processing apparatus of the present invention may also have such a constitution as a heating device is provided in the vacuum vessel for heating the reaction chamber and the assistance chamber.  
       [0031] The vacuum processing apparatus of the present invention may also constitute a multi-chamber vacuum processing apparatus which includes at least one unit of the vacuum processing apparatus described above, a heating chamber for heating substrate in vacuum atmosphere and a transfer chamber in which the substrate is moved in vacuum atmosphere, while the vacuum processing apparatus and the heating chamber are connected to the transfer chamber.  
       [0032] In the multi-chamber vacuum processing apparatus, a sputtering apparatus may be connected to the transfer chamber.  
       [0033] The present invention has the constitution as described above, where the stage moving mechanism moves the substrate stage in the vacuum vessel while maintaining vacuum atmosphere.  
       [0034] The system is so designed that the conductance of evacuation between the reaction chamber and the exhaust port is lower when the inside of the vacuum vessel is evacuated while the substrate stage is moved toward the reaction chamber, than when the inside of the vacuum vessel is evacuated while the substrate stage is moved into the assistance chamber.  
       [0035] In the vacuum processing apparatus of the present invention, the gas introduction system for introducing the raw material gas may be connected to the reaction chamber and the evacuation system may be connected to the assistance chamber. In this case, pressure of the raw material gas in the reaction chamber can be made higher even when the pressure in the assistance chamber is low, by moving the substrate stage toward the reaction chamber and introducing the raw material gas into the reaction chamber while evacuating the inside of the assistance chamber by means of the vacuum pumping system.  
       [0036] Since the conductance of evacuation becomes higher when the introduction of the raw material gas is stopped and the substrate stage is moved into the assistance chamber, residual gas in the reaction chamber can be rapidly removed to the outside. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0037]FIG. 1 shows the vacuum processing apparatus of a first example of the present invention;  
     [0038]FIG. 2 shows the operation of transferring the substrate into the vacuum processing apparatus;  
     [0039]FIG. 3 shows the state of completing the transfer of the substrate into the vacuum processing apparatus;  
     [0040]FIG. 4 shows the state of growing the thin film in the vacuum processing apparatus;  
     [0041]FIG. 5 shows the state of evacuating residual gas in the vacuum processing apparatus;  
     [0042]FIG. 6( a ) shows the clearance between the substrate stage and the wall surface of the vacuum vessel when the substrate stage is elevated;  
     [0043]FIG. 6( b ) shows the clearance between the substrate stage and the wall surface of the vacuum vessel when the substrate stage is moved into the assistance chamber;  
     [0044]FIG. 7 shows the vacuum processing apparatus of a second example of the present invention;  
     [0045]FIG. 8 shows the state of growing the thin film in the second example of vacuum processing apparatus;  
     [0046]FIG. 9 shows the vacuum processing apparatus of a third example of the present invention;  
     [0047]FIG. 10 shows the state of growing the thin film in the third example of vacuum processing apparatus;  
     [0048]FIG. 11 is a graph showing the difference in the evacuation characteristic between the vacuum processing apparatus of the prior art and the vacuum processing apparatus of the present invention;  
     [0049]FIG. 12 is a graph showing the difference in the film thickness distribution between the vacuum processing apparatus of the prior art and the vacuum processing apparatus of the present invention;  
     [0050]FIG. 13 is a graph showing the difference in the electric characteristic of the thin film between the vacuum processing apparatus of the prior art and the vacuum processing apparatus of the present invention;  
     [0051]FIG. 14 is a block diagram showing an example of the gas generation system which can be used in the present invention;  
     [0052]FIG. 15 shows the multi-chamber vacuum processing apparatus as an example of the present invention; and  
     [0053]FIG. 16 shows the vacuum processing apparatus of the prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0054] Reference numeral  90  in FIG. 15 denotes a multi-chamber vacuum processing apparatus as an example of the present invention.  
     [0055] The multi-chamber vacuum processing apparatus  90  includes a transfer chamber  50 , a loading chamber  91 , an unloading chamber  92 , sputtering chambers  93 ,  94 , a plasma cleaning chamber  95 , a heating chamber  96  and the vacuum processing apparatus  1  of a first example of the present invention, while the chambers  1  and  91  through  96  are connected to the transfer chamber  50 .  
     [0056] Reference numeral  97  denotes an automatic loader which is used to place an unprocessed substrate into the loading chamber  91 , and take out the substrate which has been returned into the unloading chamber  92  after being processed in the multi-chamber vacuum processing apparatus  90 . Reference numeral  59  denotes a substrate transfer robot installed in the transfer chamber  50 . The substrate transfer robot  59  can operate while maintaining the vacuum atmosphere in the transfer chamber  50 .  
     [0057] Now the vacuum processing apparatus  1  of the present invention will be described below.  
     [0058] Referring to FIG. 1, the vacuum processing apparatus  1  includes a vacuum vessel  10 , a gas introduction system  30  and a vacuum pumping system  20 .  
     [0059] The gas introduction system  30  includes a gas generation system  35  which generates a raw material gas for thin film depositing a feed tube  31  extending from the gas generation system  35 , an inlet port  17  provided in the ceiling of the vacuum vessel  10  and connected to an end of the feed tube  31 , and a shower plate  12  installed in the vacuum vessel  10  near the ceiling. There is a space between the shower plate  12  and the ceiling of the vacuum vessel  10 , forming a gas storing chamber  18 .  
     [0060] Installed airtight to penetrate the bottom plate of the vacuum vessel  10  is a lift shaft  11  with the substrate stage  13  attached on top end thereof. A stage moving mechanism  29  is disposed outside the vacuum vessel  10 , while the lower portion of the lift shaft  11  is put into the stage moving mechanism  29  so as to be moved up and down by the stage moving mechanism  29  while maintaining the vacuum atmosphere in the vacuum vessel  10 .  
     [0061] By the lift shaft  11  is moved vertically, the substrate stage  13  moves between a position near the bottom of the vacuum vessel  10  and a position near the shower plate  12 .  
     [0062] Provided in a side wall of the vacuum vessel  10  at a position near the bottom is an exhaust port  28  for the vacuum pumping system  20 . Connected to the exhaust port  28  is an end of an exhaust tube  22  of which another end is connected to the vacuum pump  24 . A gate valve  23  is provided between the vacuum pump  24  and the exhaust port  28 , so that the residual gas in the vacuum vessel  10  is pumped out through the exhaust port  28  when the vacuum pump  24  is operated and the gate valve  23  is opened.  
     [0063] The vacuum vessel  10  has such a configuration as the upper portion of the vacuum vessel  10  wherein the shower plate  12  is installed has a cylindrical shape, and the lower portion to which the vacuum pumping system  20  is connected has a shape of rectangular-section tube. Reference numeral  14  denotes a reaction chamber constituted from the interior space of the cylindrical portion. Reference numeral  16  denotes an assistance chamber constituted from the inner space of the rectangular-section tube. The vacuum vessel  10  is wider in each side of the portion which constitutes the assistance chamber  16  than in the diameter of the portion which constitutes the reaction chamber  14 .  
     [0064] The vacuum vessel  10  also has a substrate loading/unloading port  25 , which can freely open or close, in a side wall of the portion thereof which constitutes the assistance chamber  16 . The vacuum processing apparatus  1  is connected by the substrate loading/unloading port  25  with the transfer chamber  50 .  
     [0065]FIG. 14 is a block diagram of the gas generation system  35  used for carrying out the MOCVD process by means of the vacuum processing apparatus  1  described above.  
     [0066] The gas generation system  35  has a plurality of raw material containers  81 . Operation for depositing a thin film of ferroelectric lead zirconate titanate (PZT) in the vacuum vessel  10  will be described below. First, organometal compounds each including one of Pb, Zr and Ti in the chemical composition thereof are dissolved in an organic solvent (THF):Tetrahydro-furan thereby to prepare three kinds of stock solution which are stored in different raw material containers  81 . The organic metal compounds are (1) through (3) described below.  
     [0067] (1) Lead bis (dipivaloylmethanate): Pb(DPM) 2    
     [0068] (2) Zirconium tetrakis (dipivaloylmethanate): Zr(DPM) 4    
     [0069] (3) Di-isopropoxy-titanium bis(dipivaloylmethanate): Ti(iPrO) 2 (DPM) 2    
     [0070] Each of the raw material containers  81  is connected via a liquid mass flow controller  82  to a spray device  83 . The spray device  83  has such a constitution as the stock solutions in the raw material containers  81  can be introduced therein at controlled flow rates.  
     [0071] The spray device  83  is also connected to a carrier gas cylinder via a gas mass flow controller  84 , so that a carrier gas (nitrogen gas in this case) can also be introduced at a controlled flow rate concurrently with the introduction of the stock solutions.  
     [0072] As the stock solutions introduced into the spray device  83  are sprayed along with the carrier gas into an evaporator  85 , the stock solution evaporates.  
     [0073] The evaporator  85  is connected to a mixer  86 , so that the carrier gas and the gases of the evaporated stock solutions can be introduced into the mixer  86 .  
     [0074] Also connected to the mixer  86  is a cylinder filled with a reaction gas (O 2  gas in this case), so that the gases are mixed to generate the raw material gas, when the reaction gas as well as the carrier gas and the gases of the evaporated stock solutions are introduced into the mixer.  
     [0075] The mixer  86  is connected by the feed tube  31  to the inlet port  17 , with the valve  32  installed amid the line. When the valve  32  is opened while the raw material gas is generated in the mixer  86 , the raw material gas is introduced into the gas storing chamber  18  via the feed tube  31 .  
     [0076] The multi-chamber vacuum processing apparatus  90  and the vacuum processing apparatus  1  of the present invention are comprised as described above. To deposit a thin film of PZT, first the sputtering chambers  93 ,  94 , the plasma cleaning chamber  95 , the heating chamber  96  and the vacuum processing apparatus  1  are pumped vacuum in advance. Then after loading the substrate, whereon the film is to be deposited in the loading chamber  91  by the automatic loader  97 , and evacuating the loading chamber  91 , the substrate transfer robot  59  is operated to load the substrate into the heating chamber  96 . The substrate is heated to a predetermined temperature (600° C.) in the heating chamber  96 .  
     [0077] In the vacuum processing apparatus  1  of the present invention, a heating device  19  provided around the exterior walls of the vacuum vessel  10  is operated to heat up the wall of the vacuum vessel  10  to a predetermined temperature (220° C.) while evacuating the inside of the vacuum vessel  10  by the vacuum pumping system  20 .  
     [0078] Meanwhile the stage moving mechanism  29  is operated to lower the substrate stage  13  into the assistance chamber  16  as shown in FIG. 2.  
     [0079] Then after opening the substrate loading/unloading port  25 , the substrate which has been heated in the heating chamber  96  is carried by the substrate transfer robot  59  into the assistance chamber  16  of the vacuum vessel  10 .  
     [0080] Reference numeral  51  in FIG. 2 denotes an arm of the substrate transfer robot  59 , with the substrate  15  being placed at a distal end  52  of the arm  51 .  
     [0081] The distal end  52  is positioned over the substrate stage  13  and the substrate  15  is transferred onto the substrate stage  13  by means of a substrate lifting mechanism not shown. Then after the arm  51  and the distal end  52  thereof are pulled out of the vacuum vessel  10 , the substrate loading/unloading port  25  is closed so as to attain the state of the substrate  15  being placed in the vacuum processing apparatus  1 .  
     [0082]FIG. 3 shows the state described above. The substrate stage  13  incorporates the heating device therein, so that the substrate  15  placed on the substrate stage  13  is maintained at a predetermined temperature by the heating device.  
     [0083] In this state and during growth of the thin film to be described later, too, the vacuum pump  24  is always in operation, and the gas existing in the vacuum vessel  10  is exhausted through the exhaust port  28 .  
     [0084] Then the substrate stage  13  is elevated by the stage moving mechanism  29 , thereby to put the substrate  15  placed on the substrate stage  13  in the reaction chamber  14  as shown in FIG. 4.  
     [0085]FIG. 6( a ) is a schematic sectional view taken along line A-A of the reaction chamber  14  in the state shown in FIG. 4 (the substrate stage  13  being elevated). The substrate stage  13  has a disk shape of a diameter 2 mm smaller than that of the reaction chamber  14 . Accordingly, clearance  26  between the side face of the substrate stage  13  and the wall surface of the vacuum vessel  10  is about 1 mm.  
     [0086] In this state, the raw material solutions of compounds including Pb, Zr and Ti (the compounds were dissolved in THF as the solvent with the concentration adjusted to 0.3 mol/liter) held in the raw material containers  81  were introduced at proper flow rates into the evaporator  85 , while the carrier gas (N 2  gas) was introduced at a flow rate of 300 sccm into the evaporator  85  at the same time.  
     [0087] The raw material solutions were evaporated in the evaporator  85 , and introduced into the mixer  86  together with the reaction gas (O 2  gas) of 2000 sccm, thereby to generate the raw material gas in the mixer  86 , and then the valve  32  was opened to introduce the gas into the gas storing chamber  18 .  
     [0088] The shower plate  12  has small holes so that the raw material gas introduced into the gas storing chamber  18  passes through the small holes of the shower plate  12  and sprayed into the reaction chamber  14 .  
     [0089] The raw material gas sprayed into the reaction chamber  14  diffuses in the reaction chamber  14  and, upon reaching the surface of the substrate  15 , undergoes chemical reaction in the portion of surface so as to deposit a thin film of ferroelectric lead zirconate titanate (PZT) on the surface of the substrate  15 .  
     [0090] Reference numeral  36  in FIG. 4 indicates the flow of the raw material gas injected through the shower plate  12  into the reaction chamber  14  and the flow of the waste gas after the raw material gas has been used to grow the thin film. These gases pass the narrow clearance  26  between the substrate stage  13  and the vacuum vessel  10 , and pass through the assistance chamber  16  to be evacuated through the exhaust port  28 .  
     [0091] When the substrate stage  13  is positioned in the reaction chamber  14 , the assistance chamber  16  which is directly connected to the exhaust port  28  is evacuated directly by the vacuum pumping system  20  and is therefore pumped to a lower pressure. In contrast, since the clearance  26  has lower conductance, the reaction chamber  14  has lower conductance of evacuation. As a result, the raw material gas injected through the small holes of the shower plate  12  remains in the reaction chamber  14 , resulting in a higher pressure in the reaction chamber  14 . When the pressure in the assistance chamber  16  was about 133 Pa with the substrate stage  13  being placed in the reaction chamber  14 , pressure in the reaction chamber  14  into which the raw material gas was sprayed was 10 times that of the assistance chamber  16 .  
     [0092] When the thin film grown on the surface of substrate  15  reaches a predetermined thickness, introduction of the raw material gas and heating of the substrate  15  are stopped. Then the stage moving mechanism  29  is actuated to lower the substrate stage  13 . FIG. 5 shows a state of the substrate stage  13  which has been lowered is positioned in the assistance chamber  16 .  
     [0093]FIG. 6( b ) is a schematic sectional view taken along line B-B of the assistance chamber  16  under this condition. Since width of the assistance chamber  16  is larger than the diameter of the reaction chamber  14 , clearance  27  between the side face of the substrate stage  13  and the wall surface of the vacuum vessel  10  is made larger. Thus the conductance of evacuation of the reaction chamber  14  is higher in this state.  
     [0094] Reference numeral  37  in FIG. 5 indicates the flow of the raw material gas remaining in the reaction chamber  14  and the flow of the waste gas which pass through the wide clearance  27  and evacuated through the exhaust port  28 . Consequently, when the substrate stage  13  is moved into the assistance chamber  16  after introduction of the raw material gas has been stopped, pressure in the vacuum vessel  10  decreases in a short time.  
     [0095]FIG. 11 is a graph showing the vacuum pumping characteristic, contrasting the vacuum pumping characteristic of the vacuum processing apparatus  1  of the present invention and the vacuum pumping characteristic of the vacuum processing apparatus  101  of the prior art.  
     [0096] In the vacuum processing apparatus  101  of the prior art, it took 13 minutes since high vacuum pumping was carried out after completing the film deposition, then the substrate was taken out, till the next substrate was carried in and film formation thereon was completed. In contrast, the process was completed in 8 minutes in the vacuum processing apparatus  1  of the present invention.  
     [0097]FIG. 12 is a graph showing the film thickness distribution of PZT across the surface of the substrate. Point  0  in the scale of abscissa is set at the center of the substrate. FIG. 13 is a graph showing the distribution of electric characteristic of the thin film of PZT which has been measured across the surface.  
     [0098] In the vacuum processing apparatus  1  of the present invention, since the raw material gas and the waste gas are rapidly evacuated after completing the deposition of the thin film, the film thickness and the electric characteristic are distributed more uniformly across the surface than in the case of the vacuum processing apparatus  101  of the prior art. In the case of the vacuum processing apparatus  101  of the prior art, in particular, since the raw material gas is likely to stay around the substrate stage when pumping out the residual gas, film thickness becomes greater along the periphery of the substrate and the electric characteristic deteriorates.  
     [0099] Now a second example of the vacuum processing apparatus of the present invention will be described below.  
     [0100] Reference numeral  2  in FIG. 7 denotes the vacuum processing apparatus of the second example. Members similar to those used in the vacuum processing apparatus  1  of the first example are denoted with the same reference numerals and description thereof are omitted.  
     [0101] A substrate stage  63  of the vacuum processing apparatus  2  has a mount  64  which has a cylindrical shape with a flat top.  
     [0102] The mount  64  has a contact portion  68  disposed around thereof at the bottom.  
     [0103] The contact portion  68  has a flange  65  of diameter larger than the outer diameter of the mount  64  and an O-ring  66  disposed on the surface of the flange  65 .  
     [0104] The cylindrical portion of the vacuum vessel  10  which constitutes the reaction chamber  14  has a diameter larger than that of the flange  65 , so that the flange  65  can be disposed in the reaction chamber  14  without making contact with the wall surface of the vacuum vessel  10 .  
     [0105] The vacuum vessel  10  is provided with a ring-shaped contact member  53  fastened onto the wall surface of the portion thereof which constitutes the reaction chamber  14 .  
     [0106] Inner diameter of the contact member  53  is made larger than the diameter of the mount  64  of the substrate stage  63 , while the mount  64  is thicker than the contact member  53 .  
     [0107] Center of the contact member  53  and centers of the mount  64  and the flange  65  are aligned on the same vertical line so that, when the stage moving mechanism  29  is actuated to elevate the substrate stage  63  out of the assistance chamber  16 , the mount  64  fits into the contact member  53  while the surface of the mount  64  protrudes upward beyond the contact member  53 .  
     [0108] The O-ring  66  is provided on the surface of the flange  65  around the mount  64 , so that top of the O-ring  66  makes contact with the back surface of the contact member  53  when the mount  64  fits in the contact member  53 . Under this condition, the contact member  53  and the substrate stage  63  make close contact with each other. For a high-temperature application, an O-ring made of a metal may be used for the O-ring  66 .  
     [0109]FIG. 8 shows the state of the contact member  53  and the substrate stage  63  making close contact with each other, attained by placing the substrate  15  on the mount  64  in the assistance chamber  16 , then moving the substrate stage  63  upward. In this state, the surface of the substrate  15  is exposed into the reaction chamber  14 .  
     [0110] The contact member  53  has a plurality of holes  54 , so that the reaction chamber  14  and the assistance chamber  16  are communicated with each other by the holes  54 .  
     [0111] In this state, the space above the contact member  53  constitutes the reaction chamber  14 . The raw material gas injected through the small holes of the shower plate  12  fills the reaction chamber  14 . Then the raw material gas which has not reacted and the waste gas after reaction enter the assistance chamber  16  through the hole  54 , and are exhausted out through the exhaust port  28 .  
     [0112] Under this condition, since the reaction chamber  14  has the same conductance of evacuation as that of the holes  54 , pressure in the reaction chamber  14  becomes higher than that in the assistance chamber  16 .  
     [0113] After the thin film has been deposited, introduction of the raw material gas is stopped and the substrate stage  63  is lowered so that the substrate stage  63  departs from the contact member  53 . Thus the distance between the substrate stage  63  and the wall surface of the vacuum vessel  10  increases so that the conductance of evacuation of the reaction chamber  14  increases, and the residual gas in the reaction chamber  14  is rapidly evacuated.  
     [0114] Thus in the vacuum processing apparatus  2  of the second example of the present invention, as in the vacuum processing apparatus  1  of the first example, the conductance of evacuation of the reaction chamber  14  is low when the substrate  15  is positioned in the reaction chamber  14 . The conductance of evacuation of the reaction chamber  14  becomes higher when the substrate  15  is retreated into the assistance chamber  16  than the conduction when the substrate  15  is positioned in the reaction chamber.  
     [0115] As a result, pressure of the raw material gas in the reaction vessel  14  can be increased when growing the thin film, while the speed of exhausting of the reaction chamber  14  and the assistance chamber  16  can be increased when evacuating the residual gas.  
     [0116] Particularly in the vacuum processing apparatus  2  of the second example, the conductance of evacuation of the reaction chamber  14  when growing the thin film can be controlled by changing the size and number of the holes  54  of the contact member  53 .  
     [0117] The vacuum processing apparatuses  1 ,  2  wherein the assistance chamber  16  is located below the reaction chamber  14  have been described, although the present invention is not limited to these constitutions.  
     [0118] Reference numeral  3  in FIG. 9 denotes the vacuum processing apparatus of the third example of the present invention, having a vacuum vessel  70  wherein an assistance chamber  76  is located at a position sideways below the reaction chamber  14 . The inside of the vacuum vessel  70  is evacuated by the vacuum pumping system  20  when carrying in the substrate, when growing the thin film and after the thin film has been deposited, similarly to the cases of the vacuum processing apparatuses  1 ,  2 .  
     [0119] In the vacuum processing apparatus  3 , the substrate stage  73  is positioned in the assistance chamber  76  and the substrate  15  is placed on the substrate stage  73 . Then the stage moving mechanism  39  is actuated to extend a transfer shaft  21  sideways thereby to move the substrate stage  73  horizontally and put the substrate  15  in the reaction chamber  14 .  
     [0120]FIG. 10 shows the state described above, in which the distance between the substrate  15  and the vacuum vessel  70  is small and therefore the conductance of evacuation of the reaction chamber  14  is low.  
     [0121] As the raw material gas is injected through the small holes of the shower plate  12  into the reaction chamber  14  to deposit the thin film on the substrate  15  and then the substrate stage  73  is retreated into the assistance chamber  76 , the conductance of evacuation of the reaction chamber  14  increases so that the residual gas in the reaction chamber  14  is rapidly exhausted by vacuum pumping.  
     [0122] Thus since the conductance of evacuation between the reaction chamber  14  and the exhaust port  28  is high when the substrate stage  73  is retreated into the assistance chamber  76 , the residual gas in the reaction chamber  14  is rapidly exhausted by vacuum pumping. The assistance chamber  76  and the reaction chamber  14  may be partitioned from each other when growing the thin film.  
     [0123] Similar effects of uniformity for thickness and distribution of electric characteristic of the thin film have been deposited with other raw materials, for example, in the growth of (Ba, Sr)TiO 3  thin film. The raw materials used in this case were Ba(DPM) 2 , Sr(DPM) 2 , Ti(iPrO) 2 (DPM) 2 , of which solutions with a concentration of 0.3 mol/liter were supplied at a flow rate of 0.6 ml/min. The present invention can be applied to the CVD process for wide applications including Pt, Ir, Ru, SrRuO 3 , WN and TiN.  
     [0124] The vacuum processing apparatuses  1  through  3  where the MOCVD process is employed have been described, although the present invention is not limited to these constitutions. The present invention can be applied to vacuum processing apparatuses in general wherein gas is introduced into vacuum atmosphere and decomposed on a substrate, and the gas remaining therein after completing the process is rapidly exhaused by vacuum pump. For example, the present invention may also be applied to an etching apparatus or a surface modification apparatus wherein a gas is introduced into vacuum atmosphere.  
     [0125] Time required to exhaust the residual gas is reduced since the conductance of evacuation when pumping out the residual gas can be made higher than that during growth of the thin film.  
     [0126] Since the substrate is transferred into the vacuum processing apparatus after being heated to a predetermined temperature, the period of heating the substrate in the vacuum processing apparatus is eliminated.