Abstract:
A vacuum apparatus, which conveys a large-sized substrate and saves space, is provided. The vacuum apparatus of the present invention comprises pluralities of lower rollers, pressing rollers and pressing mechanisms. Since the substrate is sandwiched by the lower rollers and the pressing rollers at a position between the conveying roller and the conveying roller, the substrate does not fall down. The substrate contacts the pressing rollers and pushes the pressing roller back, and is sandwiched between the pressing roller and the lower roller, so that the substrate is not damaged when sandwiched.

Description:
[0001]    This is a Continuation of International Application No. PCT/JP2008/052823 filed on Feb. 20, 2008, which claims priority of Japan Patent Document No. 2007-056629 filed on Mar. 7, 2007. The entire disclosure of the prior application is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND 
       [0002]    The present invention generally relates to a technical field of a vacuum apparatus; and more particularly, to a vacuum apparatus having a device for conveying a substrate, while standing it at a nearly vertical angle. 
         [0003]    Conventionally, a substrate in a horizontal posture is placed on a hand of a substrate conveying robot; and the substrate is conveyed still in the horizontal posture by expanding and shrinking the hand. Alternatively, a substrate in a horizontal posture is placed on a plurality of rollers having rotary axes horizontally arranged to convey it by rotating the rollers, while the horizontal posture is being maintained. 
         [0004]    However, in such vacuum apparatuses, as substrates become larger, the required installation area also becomes larger. 
         [0005]    Under these circumstances, a vacuum apparatus, which conveys a substrate without being set in a horizontal posture, has recently been proposed. For example, techniques are proposed, in which a substrate fitted into a frame is conveyed in a vertical posture, or conveying rollers are arranged in a line on a bottom wall of a vacuum chamber, and a substrate is placed on the conveying rollers standing to be conveyed in an approximately vertical posture by rotating the conveying rollers. 
         [0006]    However, when the substrate is conveyed in the vertical posture, it is feared that the substrate falls down from the conveying rollers. In order to prevent the falling down of the substrate, it is suggested that recessed grooves are provided at peripheral faces of the conveying rollers. When the recessed grooves are provided, however, there is a possibility that the substrate may bump against a wall of the recessed groove during the conveyance, thereby resulting in the substrate being damaged. 
         [0007]    See, Japanese Patent Document JP-A 10-265018. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention, which has been made to solve the above problems, is aimed at providing a conveying apparatus capable of conveying a substrate in an approximately vertical posture. 
         [0009]    Specifically, the invention is aimed at providing a conveying apparatus capable of conveying a large-sized and thin substrate in an approximately vertical posture without breaking the substrate during the conveyance. 
         [0010]    In order to solve the above problems, the present invention is directed to a vacuum apparatus comprising a vacuum chamber, a plurality of conveying rollers located on a side of a bottom wall inside the vacuum chamber and arranged along a direction in which a single conveying straight line extends, a plurality of upper rollers located on a side of a ceiling of the vacuum chamber and arranged along the direction in which the conveying straight line extends, and rotating devices for rotating the conveying rollers around rotary axes, respectively. The conveying rollers are arranged such that the rotary axes are in parallel to each other and peripheral faces contact with a line identical to the conveying straight line. When the substrate is placed on the peripheral faces of the conveying rollers in a conveying posture in which the substrate is directed to a direction along the conveying straight line in the state of being inclined at a predetermined inclination angle from a vertical axis; and the upper rollers are arranged at positions in which their peripheral faces contact the lower one of the surfaces of the substrate which is directed downwardly. When the conveying rollers rotate and the substrate on the conveying rollers moves in the direction along the conveying straight line while maintaining the conveying posture, the upper rollers rotate while contacting an upper portion of the lower surface of the substrate. The vacuum apparatus further includes a plurality of lower rollers, a plurality of pressing rollers and pressing mechanisms consisting of springs, wherein the positions of rotary axes of the lower rollers are immobilized relative to the vacuum chamber; the pressing rollers are pressed to the lower rollers by the pressing mechanism such that the pressing rollers can be pushed back. The lower rollers are disposed at positions in which peripheral faces are capable of contacting a lower portion of the lower surface of the substrate in the conveying posture on the conveying rollers. When the substrate moves in the conveying posture on the conveying rollers, the substrate is inserted between the lower rollers and the pressing rollers by pushing the pressing rollers back; and the substrate moves, while the lower rollers and the pressing rollers are being rotated, in a state such that the substrate is sandwiched by the lower rollers and the pressing rollers. 
         [0011]    The present invention is directed to a vacuum apparatus, wherein the rotary axes of the conveying rollers are inclined at a predetermined angle from a horizontal plane. The peripheral faces of the lower rollers and the peripheral faces of the upper rollers are arranged in positions in which the peripheral faces contact a single flat plane containing the conveying straight line and inclined at the inclined angle. 
         [0012]    The present invention is also directed to the vacuum apparatus, wherein the upper rollers and the conveying rollers are such that the rotary axes of the upper rollers are inclined at the inclination angle from the vertical axis; and the rotary axes of the conveying rollers are inclined at the inclination angle from the horizontal plane. 
         [0013]    The present invention is directed to the vacuum apparatus, further comprising a heater for heating the substrate being provided at a position opposed to the lower surface of the substrate on the conveying rollers. 
         [0014]    The present invention is also directed to a vacuum apparatus, wherein a target is arranged at a position opposed to the upper surface of the substrate on the conveying rollers which is directed upwardly. 
         [0015]    The present invention is also directed to a vacuum apparatus, wherein a sputtering gas feeding system is connected to the vacuum chamber, and a sputtering power source is connected to the target. 
         [0016]    Moreover, the present invention is a method for conveying a substrate, comprising the steps of: arranging a plurality of conveying rollers, which have rotary axes inclined at a predetermined angle from a horizontal plane, along a direction in which a single conveying straight line extends; arranging a plurality of upper rollers at positions above the conveying rollers; arranging the substrate in a conveying posture in which the substrate is inclined at a predetermined inclination angle from a vertical direction in the state of one side of a lower end of the substrate contacting with peripheral faces of at least two conveying rollers; contacting an upper portion of the lower surface directed downwardly of the substrate in the conveying posture with peripheral faces of the upper rollers; conveying the substrate in the conveying posture, while the conveying rollers and the upper rollers are rotating; arranging a plurality of lower rollers, along the direction in which the conveying straight line extends, at positions in which they can contact a lower portion of the lower surface of the substrate in the conveying posture on the conveying rollers; arranging the pressing rollers, with urging forces applied in a direction of the lower rollers, in such positions that the pressing rollers can contact the lower portion of the upper surface of the substrate directed upwardly; heating the lower surface of the substrate at a higher temperature than the upper surface of the substrate, so that the lower surface is made convex and the surface on the opposite side is made concave; contacting the lower portion of the substrate moving on the conveying rollers with the pressing rollers; pressing the lower portion of the upper surface of the substrate with the pressing rollers in directions of the lower rollers when the substrate enters between the lower roller and the pressing roller; and moving the substrate, in such a state that the lower end of the substrate is sandwiched by the lower rollers and the pressing rollers. 
         [0017]    Since the present invention is constructed as discussed above and the substrate cannot be placed if the rotary axes of the conveying rollers are vertical, the angle formed between the rotary shaft and the horizontal plane is at least 0 degree and at most 90 degrees at a maximum. The angle between the rotary axis of the conveying roller and the horizontal plane can be set to the same as the inclination angle θ (an angle of 2° to 5° 0  as one example) of the substrate. 
         [0018]    When the substrate on the conveying rollers is not in contact with the peripheral faces of the lower rollers, the peripheral faces of the lower rollers are in contact with the peripheral faces of the pressing rollers. From that state, as the substrate inclined at the inclination angle approaches the conveying rollers and the lower surface of the substrate contacts the peripheral face of the lower roller, the substrate collides near an outer periphery of the peripheral face of the pressing roller, and is inserted between the peripheral face of the lower roller and that of the pressing roller by pushing aside the pressing roller. In this state, the substrate is sandwiched between the lower roller and the pressing roller. 
         [0019]    The pressing mechanism provides the pressing roller with a pressing force in order to press the pressing roller to the lower roller, so that the pressing roller presses the substrate toward the lower roller and presses the substrate to the peripheral face of the lower roller. 
         [0020]    This substrate also contacts the peripheral face of the upper roller, so that when the substrate contacts the peripheral face of the upper roller and the peripheral face of the lower roller, the substrate remains on the peripheral face of the conveying roller, while it is inclined at the inclination angle θ from the vertical direction. Therefore, the substrate will not slip off from the conveying roller. 
         [0021]    The upper rollers, the lower rollers and the pressing rollers are arranged such that when the substrate is placed on the peripheral faces of the conveying rollers while inclined at the inclination angle θ from the vertical direction and moves in that state by the rotation of the conveying rollers, the upper rollers, the lower rollers and the pressing rollers rotate without slipping from the surfaces of the substrate. Thus, the substrate is not scratched and dust is not generated. 
         [0022]    When the substrate inclined at the inclination angle θ on the conveying roller moves horizontally in a state such that it is positioned within the same plane, the rollers do not slide with the surfaces of the substrate if the rotary axes of the upper rollers, the lower rollers and the pressing rollers are arranged along a direction vertical to the moving direction of the substrate and also in a direction inclined at the inclination angle θ from the vertical direction. 
         [0023]    The extending direction of the rotary axis of the upper roller and the extending direction of the rotary axis of the lower roller are vertical to the extending direction of the rotary axis of the conveying roller. 
         [0024]    Since the substrate is conveyed in a posture that is nearly vertical, and not horizontal, the installation space of the vacuum apparatus can be small even if large substrates are to be conveyed. Since the substrate is held sandwiched between the pressing rollers and the lower rollers, it does not fall down from the conveying rollers. Since the substrate does not bump against the lower roller, it is not damaged. The substrate can be conveyed even if a carrier is not used. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0025]      FIG. 1  is a schematic perspective view of the interior for illustrating a vacuum apparatus. 
           [0026]      FIG. 2  is a schematic perspective view of the interior for showing a state in which the substrate is placed on conveyer rollers. 
           [0027]      FIG. 3  is a sectional view for showing a state in which the substrate is placed on the conveying roller. 
           [0028]      FIGS. 4(   a ) and ( b ) are side views for illustrating positional relationships among the conveyer roller, an upper roller and the substrate. 
           [0029]      FIG. 5  is a side view for illustrating a positional relation between a falling down-preventing device and the upper roller. 
           [0030]      FIGS. 6(   a ) and ( b ) are side views for illustrating falling down-preventing devices. 
           [0031]      FIG. 7  is an enlarged side view showing a state in which the substrate is positioned by the falling-down preventing device. 
           [0032]      FIG. 8  is a block diagram for illustrating the vacuum apparatus. 
           [0033]      FIG. 9(   a ) is a sectional view for illustrating a conventional conveying roller; and  FIG. 9(   b ) is a sectional view for illustrating the conveying roller to be used in the present invention. 
           [0034]      FIG. 10  is a figure for illustrating a manner of curving the substrate. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]      FIG. 8  is a block diagram of a vacuum system  1 . 
         [0036]    The vacuum system  1  comprises a carry-in chamber  11 , a heating chamber  12 , a vacuum apparatus  20 , and a carry-out chamber  14 . Vacuum evacuation systems  19   a  to  19   d  are configured to be connected to the carry-in chamber  11 , the heating chamber  12 , the vacuum apparatus  20 , and the carry-out chamber  14 , respectively, so that they can be discretely evacuated to a vacuum state. 
         [0037]    The carry-in chamber  11 , the heating chamber  12 , the vacuum apparatus  20 , and the carry-out chamber  14  are connected in this order, so that the substrate disposed in the carry-in chamber  11  is heated, and processed inside the vacuum apparatus  20 , and then carried out from the carry-out chamber  14 . 
         [0038]      FIG. 1  is a schematic perspective view of the interior for illustrating the vacuum apparatus  20 . 
         [0039]    This vacuum apparatus  20  comprises a vacuum chamber  21 , and a plurality of conveying rollers  23  are arranged on a bottom wall of the vacuum chamber  21 , while falling down-preventing devices  30  are arranged between the conveying rollers  23 . 
         [0040]    Each of rollers including the conveying rollers  23  is of an approximately discoidal shape or an approximately cylindrical shape, and is configured to rotate around a rotary axis passing the center of a bottom face of the disc or the cylinder, while the peripheral face makes a circular motion. Assuming that the cylindrical shape is constituted by two bottom faces and a ring-shape peripheral face connected to outer peripheries of the two bottom faces, the peripheral face of the roller (such as, the conveying roller  23  or the like) refers to a ring-shaped circular peripheral face. 
         [0041]    The rotary axes “d” of the respective conveyor rollers  23  are disposed in parallel with one another, while inclined at a predetermined inclination angle θ from a horizontal plane “h” ( FIG. 4(   a )). 
         [0042]    The center of each conveying roller  23  is arranged on an identical straight line. Each conveying roller  23  is made of a disk with the same diameter and the same thickness, so that the upper portion of the peripheral face of each conveying roller  23  contacts an identical straight line. 
         [0043]    When this straight line is called a conveying straight line, a reference numeral “c” in  FIG. 1  denotes this conveying straight line, and the direction of the conveying straight line “c” is orthogonal to a direction in which the rotary axis “d” of each conveying roller  23  extends. 
         [0044]    The substrate to be processed in this vacuum apparatus  20  is a quadrangle shape (such as a rectangular shape, a square shape or the like), and surfaces of the substrate are six in total, which include both surfaces of the substrate (front and rear surfaces) as well as four side faces defining the thickness of the substrate. 
         [0045]    When the posture of a substrate  7 , which is inclined in the same direction as the conveying roller  23  by an inclination angle θ from a vertical axis and is directed to the direction along the conveying straight line, is called a conveying posture, the substrate  7  in the conveying posture can contact the upper end of the conveying roller  23  by aligning it with the conveying straight line with one of the four side faces directed downwardly. 
         [0046]      FIG. 2  shows a state in which the substrate  7  in the conveying posture is placed on the conveying rollers  23 . The conveying roller  23  is configured such that the substrate  7  in the conveying posture does not fall down from on the plurality of conveying rollers  23  due to contact with the peripheral faces of the conveying rollers  23 . 
         [0047]    Upper main poles  41  are disposed at positions above the conveying rollers  23 , while vertically directed. The upper end of the upper main pole  41  is fixed to a ceiling of the vacuum chamber  21 ; and an upper roller  45  is rotatably fitted to the lower end. 
         [0048]    When one of the both surfaces (the two surfaces of the six faces other than the four side faces) of the substrate  7  in the conveying posture, which is directed downwardly (toward the bottom face of the vacuum chamber  21 ) is taken as a lower surface  47 , while the other surface directed upwardly (toward the ceiling of the vacuum chamber) is taken as an upper surface  48 , the upper roller  45  is arranged such that the peripheral face contacts near the upper edge of the lower surface  47  of the substrate  7  in the conveying posture on the conveying roller  23  ( FIG. 3 ). 
         [0049]    The upper end of the upper main pole  41  is fixed to the vacuum chamber  21 . Therefore, as shown in  FIG. 3 , the substrate  7 , which is placed in the conveying posture on the conveying roller  23  and contacts the peripheral face of the upper roller  45 , leans the upper rollers  45  so that the substrate may be supported by the upper rollers  45  without falling. 
         [0050]    Rotating devices  25  are connected to the conveying rollers  23 , and when the conveying rollers are rotated in the same direction in a state such that the substrate  7  in the conveying posture is placed thereon, the substrate  7  is moved in the direction along the conveying straight line “c” (in the direction parallel to the conveying straight line). 
         [0051]    In this embodiment, the rotary axis “e” of the upper roller  45  is arranged in order to conform with that of the upper main pole  41  ( FIG. 4(   a )). 
         [0052]    In addition, the rotary axis “e” of the upper roller  45  (and that of the upper main pole  41 ) is inclined from the vertical axis “v” at the same inclination angle θ as the inclination from the horizontal plane “h” of the conveying roller  23 , and the direction in which the rotary axis “e” of the upper roller  45  (and the below-mentioned lower roller) extends is vertical to both the direction in which the rotary axis “d” of the conveying roller  23  extends and the direction in which the conveying straight line “c” extends. (The direction of the rotary axis “e” of the upper roller  45  and the lower roller (discussed below), the direction of the rotary axis “d” of the conveying roller  23  and the direction in which the conveying straight line “c” extends are vertical to one another). 
         [0053]    When the substrate  7  moves in the conveying posture in the direction along the conveying straight line “c”, the lower surface  47  of the substrate  7  moves in a state such that it is located in the same plane. 
         [0054]    In  FIG. 4(   a ), a reference numeral a denotes a lower flat plane in which a lower surface of the substrate  7  is positioned, and the lower flat plane a intersects the circumferential peripheral face of the conveying roller  23 . The upper roller  45  is positioned such that its peripheral face contacts the lower flat plane α. Therefore, when the substrate  7  moves in the conveying posture in the direction along the conveying straight line “c”, as shown in  FIG. 4(   b ), the lower surface  47  of the surfaces of the substrate  7  contacts the peripheral face of the upper roller  45  so that the upper roller  45  may rotate following the movement of the substrate  7  without sliding. 
         [0055]    Meanwhile, a space between the conveying roller  23  and the conveying roller  23 , and a space between the upper roller  45  and the upper roller  45  are set such that at least two conveying rollers  23  and at least two upper rollers  45  contact the moving substrate  7  when the substrate  7  moves. Accordingly, the substrate  7  does not fall down between the conveying roller  23  and the conveying roller  23  or toward the rear side of the upper rollers  45 . 
         [0056]    In this case, the substrate  7  is made of glass; consequently, if the substrate  7  is bent or the moving direction is deviated, the substrate  7  drops off from the conveying rollers  23 , and subsequently falls down. In the configuration of the vacuum apparatus  20  of the present invention, falling-down preventing devices  30  are arranged between the conveying roller  23  and the conveying roller  23 , thus the substrate  7  on the conveying rollers  23  may not fall down from the conveying rollers  23  due to the falling-down preventing devices  30 . 
         [0057]    Next, the falling-down preventing device  30  will be explained. As shown in  FIG. 5  and  FIGS. 6(   a ) and ( b ), the falling-down preventing device  30  comprises a lower main pole  31  and a lower roller  33 . 
         [0058]    The lower main pole  31  is directed in vertical directions, and a lower end is fixed onto the bottom wall of the vacuum chamber  21 , while a lower roller  33  is rotatably provided at an upper end. 
         [0059]    The rotary axis “f” of the lower roller  33  is inclined at the inclination angle θ from the vertical axis “v” (the same value as the inclination angle θ from the horizontal line “h” of the conveying roller  23 ) ( FIG. 5 ). 
         [0060]    The lower main pole  31  and the lower roller  33  are arranged on a side of the lower surface  47  of the substrate  7  in the conveying posture. The lower main pole  31  is provided with a support pole  37  via an arm member  35 . 
         [0061]    The arm member  35  is projected up toward a side of the upper surface  48  facing upward (toward the ceiling)of the substrate  7  on the conveying roller  23  in the conveying posture, and the support pole  37  is erected on its tip, nearly in parallel to the lower main pole  31 . 
         [0062]    The arm member  35  is positioned below the substrate  7  on the conveying roller  23  so that the arm member  35  and the support pole  37  do not collide with the substrate  7  moving in the conveying posture on the conveying rollers  23 . 
         [0063]    A pressing roller  38  is rotatably provided at the upper end of the support pole  37 . 
         [0064]    The arm member  35  is provided with a pressing mechanism  36  (such as, a spring or the like). A force toward a direction in which the lower roller  33  is positioned is applied to the pressing roller  38  by the pressing mechanism. 
         [0065]    The lower roller  33  is arranged such that its peripheral face contacts the flat plane (a lower plane α) in which the lower surface  47  of the substrate  7  is located, and the pressing roller  38  is pressed by a force due to the pressing mechanism  36  toward a direction of the portion of the peripheral face of the lower roller  33  which contacts the substrate  7 . 
         [0066]    As shown in  FIG. 6(   a ), when the lower roller  33  is not in contact with the substrate  7 , the peripheral face of the pressing roller  38  may either be pressed to contact the peripheral face of the lower roller  33  or may be spaced from the peripheral face of the lower roller  33  at an interval narrower than the thickness of the substrate  7 . 
         [0067]    When the substrate  7  in the conveying posture on the conveying rollers  23  leaning against the upper rollers  33  moves in the direction along the conveying straight line “c” and approaches the pressing roller  38  pressed against the lower roller  33 , a side face of the tip of the substrate  7  first collides with the pressing roller  38 , and as the substrate  7  continues to move, it applies a force towards the opposite direction to the force applied from the pressing mechanism  36  to the pressing force  38 , while the pressing roller  38  is pushed back by the thickness of the substrate  7  so as to enter the substrate between the pressing roller  38  and the lower roller  33  ( FIG. 7 ) 
         [0068]    In this state, the substrate  7  is sandwiched by the lower rollers  33  and the pressing rollers  38 ; and the lower surface  47  of the substrate  7  contacts the lower rollers  33 , while the peripheral faces of the pressing rollers  38  are pressed against the portions of the substrate  7  exactly in reverse of these contacted positions. Therefore, the substrate  7  is pressed to the lower roller  33  by a restoring force by which the pressing roller  38  is to be returned to an original position. 
         [0069]    The rotary axis “g” of the pressing roller  38  is in parallel to the rotary axis “f” of the lower roller  33  in a state such that the substrate  7  is sandwiched between the lower roller  33  and the pressing roller  38  ( FIG. 6(   b )). Therefore, when the substrate  7  riding on the conveying rollers  23  in the conveying posture moves in the direction of the conveying straight line “c”, while leaning against the upper rollers  45 , the lower rollers  33  and the pressing rollers  38  rotate without sliding, while contacting the lower surface  47  and the upper surface  48  of the substrate  7 , respectively. Accordingly, the lower portion of the substrate  7  is kept in contact with the lower rollers  33 , so that the substrate  7  is not dropped from the conveying rollers  23 . 
         [0070]    Respective rollers (conveying, upper, lower and pressing rollers) and pressing mechanisms, as discussed above, are provided in the heating chamber  12 , and the substrate  7  disposed inside the carry-in chamber  11  is moved in the conveying posture into the heating chamber  12 . 
         [0071]    As shown in  FIG. 10 , a heater  22  is disposed in the heating chamber  12 , and infrared rays are irradiated onto the lower flat surface of the substrate  7  in the conveying posture, so that the substrate  7  riding on the conveying rollers  23  is heated. 
         [0072]    By this heating, the lower surface  47  of the substrate  7  is heated at a higher temperature than the upper surface  48 , so that the substrate  7  is slightly curved such that the lower surface  47  is convex and the upper surface  48  is concave as a result of the difference in expansion between the surfaces of the substrate  7 . 
         [0073]    The curved substrate  7  in the conveying posture runs on the conveying rollers  23 , and when the tip portion of the substrate  7  as viewed in the moving direction collides with the pressing roller  38  inside the vacuum chamber  21 , the pressing roller  38  contacts the upper surface  48  of the tip portion of the substrate  7 , while the tip portion does not contact the lower roller  33  because of the curving of the substrate  7 . Thus, when the pressing roller  38  is pushed back, an urging force is applied to the pressing roller  38 , and the tip portion of the substrate  7  is pressed toward the lower roller  33  by the pressing roller  38 , and contacts the lower roller  33  through the removal of the curving. 
         [0074]    In this case, the vacuum apparatus  20  is a sputtering apparatus. As shown in  FIG. 3 , a target  28  is arranged on a side of the upper surface  48  of the substrate  7  carried in the conveying posture into the vacuum chamber  21 , and a heater  26  is arranged on a side of the lower surface  47 . The target  28  is constituted by disposing a plate-like target material  28   b  on a backing plate  28   a.  A film forming face of the substrate  7  is the upper surface  48 , and the film forming face is in parallel to a surface of the target material  28   b  of the target  28 . 
         [0075]    A gas feeding system  27  is connected to the vacuum chamber  21 , and a sputtering power source  29  is connected to the backing plate  28   a  of the target  28 . 
         [0076]    The interior of the vacuum chamber  21  is evacuated to vacuum, a sputtering gas (such as, an Ar gas or the like) is introduced from the gas feeding system  27  so as to set the interior of the vacuum chamber  21  to a predetermined pressure, and a voltage is applied to the target  28  by the sputtering power source  29 . Accordingly, a plasma is formed near the surface of the target  28 , and the surface of the target material  28   b  is sputtered. 
         [0077]    When the substrate  7  is set in the conveying posture and moved by the respective rollers, the rotating devices  25  and the falling down-preventing devices  30 , with the film-forming surface kept in parallel to the target  28 , a thin film is grown on the film forming surface of the substrate  7 . 
         [0078]    The substrate  7  is moved, in the conveying state, into the carry-out chamber  14 , and taken out to the atmosphere. 
         [0079]    As explained above, in the vacuum apparatus  20  of the present invention, the substrate  7  on the conveying rollers  23  are held on the conveying rollers  23  by the falling down-preventing devices  30 . On the other hand, in the conventional technique, as shown in  FIG. 9(   a ), the substrate  107  is prevented from falling down by forming a recessed groove  125  at a peripheral face of a conveying roller  123  and accommodating it on a bottom face of the recessed groove  125 . As shown in  FIG. 9(   b ), according to the present invention, since no recessed groove  125  needs to be formed in the conveying roller  23 , there is no fear in the substrate  7  bumping against wall portions  129  of the recessed groove  125 . 
         [0080]    Meanwhile, the conveying roller  23  of the vacuum apparatus  20  of the present invention can be provided with a recessed groove  125 , as shown in  FIG. 9(   a ). 
         [0081]    If the relative positional relation of the upper roller  45  to the conveying roller  123  is determined such that the substrate  7  may be placed on the center of the conveying roller  123  in the thickness direction thereof, the substrate is positioned by the falling-down preventing device  30  such that the substrate  7  may not deviate from that position. Consequently, the substrate  7  does not bump against the wall portions  129  of the recessed groove  125 .