Abstract:
A load lock chamber sized for a large area substrate is provided. The load lock chamber includes a housing comprising a door and a body having at least two sealable ports, a movable door associated with at least one of the sealable ports, and a door actuation assembly coupled between the door and the housing. The door actuation assembly further includes a pair of first actuators coupled to the door for moving the door in a first direction, and a pair of second actuators for moving the door in a second direction that is orthogonal to the first direction.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the present invention relate to a selectively sealing an opening in a vacuum chamber. More particularly, to selectively sealing an opening in an evacuable transfer chamber. 
         [0003]    2. Description of the Related Art 
         [0004]    Semiconductor processes for large area substrates in the production of flat panel displays, solar cell arrays, and other electronic devices include processes such as deposition, etching, and testing, which are conventionally conducted in a vacuum processing chamber. To increase fabrication efficiency and/or lower production costs of the various end uses of the processed substrate, the large area substrates are currently about 2,200 mm× about 2,600 mm, and larger. The substrates are typically transferred into and out of the vacuum processing chamber through a transfer chamber that functions as an atmospheric/vacuum interface and is generally referred to as a load lock chamber. The load lock chamber provides a staged vacuum between atmospheric pressure and a pressure within the vacuum processing chamber. In some systems, the load lock chamber may be configured as a transfer interface between a queuing system at ambient pressure and the vacuum processing chamber providing for atmospheric to vacuum substrate exchange. Likewise, processed substrates may be transferred out of the vacuum processing chamber to atmospheric conditions through the load lock chamber. 
         [0005]    The openings in the vacuum processing chambers and the load lock chambers are generally sized to receive at least one dimension (i.e. width or length) of the large area substrate to facilitate transfer of the substrate. The chamber openings are configured to be selectively opened and closed by a door to facilitate transfer of the substrate and vacuum sealing of the chamber. The operation of the door and effective sealing of the opening creates challenges to making and using of the chambers. 
         [0006]    Therefore, there is a need for a vacuum chamber door that addresses these challenges. 
       SUMMARY OF THE INVENTION 
       [0007]    Embodiments of the present invention generally provide a door actuation assembly for a vacuum chamber sized for one or more large area substrates. In one embodiment, a vacuum chamber sized for a large area substrate is described. The vacuum chamber includes a housing comprising a body having at least one sealable port, a movable door coupled with the sealable port, and a door actuation assembly coupling the door and the housing. The door actuation assembly comprises first actuators coupled to the door for moving the door in a first direction, and second actuators for moving the door in a second direction, the second direction orthogonal to the first direction. 
         [0008]    In another embodiment, a vacuum chamber sized for a large area substrate is described. The vacuum chamber includes a housing comprising a body having at least one sealable port, a movable door coupled with the sealable port, and a door actuation assembly coupling the door and the housing. The door actuation assembly comprises a pair of first actuators coupled to the door for moving the door in a first direction, a pair of linear guides coupled between opposing ends of the door and the housing, and a pair of second actuators coupled to the linear guides and movable with the door, for moving the door in a second direction orthogonal to the first direction. 
         [0009]    In another embodiment, a method for selectively opening and closing a sealable port in a vacuum chamber for processing a large area substrate, wherein the vacuum chamber comprises a housing, a door associated with the sealable port, the door movably coupled to a linear guide on opposing ends thereof, and a moving mechanism having a pair of first actuators and a pair of second actuators is described. The method includes synchronously driving the first actuators coupled to the door, detecting a position of the door, returning a positional metric corresponding to the position of the door, and adjusting a moving speed of the first actuators based on the positional metric to ensure a longitudinal dimension of the door remains substantially orthogonal to a travel path of at least one of the linear guides coupled to the door. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0011]      FIG. 1A  illustrates an isometric view of a load lock chamber according to one embodiment of the present invention. 
           [0012]      FIG. 1B  illustrates the load lock chamber shown in  FIG. 1A  in a more detail. 
           [0013]      FIG. 2A  illustrates the implementation of a horizontal actuator according to one implementation of the present invention. 
           [0014]      FIG. 2B  illustrates the operation of the horizontal actuator according to one embodiment of the present invention. 
           [0015]      FIG. 2C  illustrates the operation of the horizontal actuator according to another embodiment of the present invention. 
           [0016]      FIG. 3  illustrates the operation of the load lock chamber according to one embodiment of the present invention. 
       
    
    
       [0017]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
       DETAILED DESCRIPTION 
       [0018]    Embodiments described herein relate to a system and method for selectively sealing a chamber opening that is adapted to contain one or more large area substrates in low pressure conditions. In one embodiment, the chamber may be configured for transferring substrates to and from ambient atmosphere and a vacuum environment. Although some embodiments are exemplarily described for use in evacuable transfer chambers, such as load lock chambers or other chambers configured to provide an atmospheric/vacuum interface, some embodiments may be applicable for other chambers configured for other low pressure processes. Examples include, without limitations, processing chambers, testing chambers, deposition chambers, etch chambers, and thermal treatment chambers. Substrates, as described herein, include large area substrates made of glass, a polymer material, or other material suitable for forming electronic devices thereon, that are configured for flat panel display production, solar cell array production, and other electronic devices that may be formed on large area substrates. Examples include thin film transistors (TFT&#39;s ), organic light emitting diodes (OLED&#39;s ), and p-i-n junctions or other devices used in the manufacture of solar arrays and/or photovoltaic cells. 
         [0019]      FIG. 1A  is an isometric view illustrating one embodiment of a load lock chamber  100 , which includes a sealable housing  110  disposed on a support frame  105 . The housing  110  comprises a body  132 , sidewalls  135 , a bottom (not shown in this view), and a lid  130 . The housing  110  has a first end  115  and a second end  120 , each of which includes a sealable opening or port  123  (shown in phantom). At least one of the sealable ports  123  is selectively opened and closed by an in/out (I/O) door  122  (shown in a closed position in  FIG. 1A  and in an open position in  FIG. 1B ). The second end  120  may be a processing interface adapted to be coupled to and in selective communication with a vacuum processing chamber  150  configured for processing a large area substrate, such as a deposition chamber, an etch chamber, a testing chamber, and the like. The first end  115  may be an atmospheric interface, which may be an interface for an atmospheric robot, an atmospheric substrate queuing system, a conveyor device or other transfer device (not shown) disposed in a clean room. 
         [0020]    The load lock chamber  100  includes a pair of first actuators  116  that are coupled to the I/O door  122  and the support frame  105 . Each of the first actuators  116  are linear actuators that may be driven electrically, hydraulically, pneumatically, and combinations thereof. Examples of the first actuators  116  include an air cylinder, an electromechanically-operated cylinder, a hydraulic cylinder, a mechanically operated cylinder, and combinations of the above. The first actuators  116  are configured to synchronously raise and lower the I/O door  122  in at least a vertical (Z) direction. The first actuators  116  are also adapted to move the I/O door  122  in a substantially parallel orientation relative to the port  123 . To facilitate parallel lifting and lowering of the I/O door  122 , the I/O door  122  is coupled to two linear bearing blocks  124  respectively mounted at two ends  125 A and  125 B of the I/O door  122 . The linear bearing blocks  124  are mounted to the sidewalls  135  of the load lock chamber  100 . In one embodiment, the first actuators  116  may be horizontally spaced apart from each other to ensure uniform vertical (Z directional) movement of the I/O door  122 . 
         [0021]    In addition to vertical movement, the I/O door  122  is also adapted to move horizontally (X direction) facilitated by a pair of second actuators  126  respectively mounted on the two lateral ends  125 A and  125 B of the I/O door  122 . The horizontal actuator blocks  126  are operable to move the I/O door  122  either toward the first end  115  for closing the sealable port  123 , or away from the first end  115  for opening the sealable port  123 . The second end  120  may also include another I/O door, another pair of linear bearing blocks, and another pair of first and second actuators, all of which are not shown. 
         [0022]    As shown in  FIG. 1B , the first end  115  of the housing  110  also includes an o-ring  136  that surrounds the sealable port  123 . In the closed position, an inner surface of the I/O door  122  tightly contacts with the o-ring  136  to seal the port  123 . In one embodiment, the o-ring  136  may be made of a plastic, resin, or other suitable materials adapted to ensure sealing of the port  123 . As the o-ring  136  is mounted on the face of the housing  110 , the o-ring  136  can be easily accessed for repair or replacement by moving the I/O door  122  to the open position, as shown in  FIG. 1B . 
         [0023]    In one embodiment, one or more position sensors  164  may also be coupled to each of the linear bearing blocks  124 . The position sensors  164  are configured to transmit detection signals reflecting the respective positions of the lateral ends  125 A and  125 B of the I/O door  122  to a controller  166  coupled to each of the first actuators  116 . In one embodiment, each sensor  164  may be a transducer, a Hall effect sensor, a proximity sensor, a linear encoder, such as encoder tape, and combinations thereof. In other embodiments, each of the first actuators  116  may include a position sensor (not shown), such as a rotary encoder or a shaft encoder adapted to provide a positional metric of each first actuator  116 . 
         [0024]    The controller  166  is also coupled to each of the second actuators  126 . The controller  166  is adapted to receive a metric from each sensor  164  indicative of movement of the of the I/O door  122  relative to the bearing blocks  124 . The controller  166  may process the movement information to control the directional movement and/or directional speed of one or both of the first actuators  116 . The controller  166  is also adapted to receive positional information from the sensors  164  to actuate the second actuators  126  to facilitate horizontal movement of the I/O door  122 . The lifting and lowering speed of each first actuator  116  can thereby be accurately controlled to prevent misalignment of the I/O door  122  relative to the bearing blocks  124  during lifting and lowering of the I/O door  122 . The misalignment of the I/O door  122  relative to the bearing blocks  124  may occur if a single actuator is used to lift/lower the I/O door  122 , in which case that actuator is disposed to be in contact with the center of the bottom of the I/O door  122 . However, supporting the I/O door  122  with single actuator may cause a wobbling of the I/O door  122  over the course of the lifting/lowering thereof, especially when the I/O door  122  becomes much wider to accommodate the transfer of larger substrate. Such wobbling or misalignment might lead to jamming of linear bearing blocks  124 . 
         [0025]      FIG. 2A  is an isometric view illustrating one embodiment of an actuating mechanism  200  for an I/O door  122 . The actuating mechanism  200  for the I/O door  122  comprises a pair of first actuators  116  adapted to drive vertical movements of the I/O door  122  along linear bearing blocks  124  and a pair of second actuators  126  providing horizontal movement of the I/O door  122 , such as in the X direction or perpendicular to the plane of the I/O door  122 . Each of the first actuators  116  has a first end coupled to the I/O door  122  at a first pivot link  210 , and a second end coupled to the support frame  105  at a second pivot link  212 . The first pivot link  210  may be rod-eye coupling or rod-clevis coupling adapted to swivel to prevent binding due to difference in speed and/or position between the first actuators  116 . A rotational axis  220  of the first pivot links  210  and a rotational axis  222  of the second pivot links  212  are parallel to each other. The first and second pivot links  210  and  212  are thereby adapted to allow movements of the I/O door  122  in the horizontal direction (X direction) caused by the horizontal actuator blocks  126 . 
         [0026]    In one embodiment, the first actuators  116  are adapted to maintain the horizontal plane (X direction) of the I/O door  122  in an orthogonal relation relative to the linear bearing blocks  124 . For example, the linear bearing blocks  124  include a longitudinal axis A and the I/O door  122  includes a longitudinal axis B. Based on positional information from the sensors  164 , an angle α of about 90° may be maintained during lifting and lowering of the I/O door  122 . This prevents misalignment of the I/O door  122  during lifting and lowering. 
         [0027]      FIG. 2B  is an enlarged view illustrating the construction of one horizontal actuator block  126 . The horizontal actuator block  126  includes a bracket  231 , a link shaft  233  and an actuator shaft  237 . The link shaft  233  has a first end fixedly secured to the bracket  231 , and a second end slidably passing through a hole (not shown) in the I/O door  122 . The bracket  231  is thereby movable with the I/O door  122  along the linear bearing block  124 . The bracket  231  provides support for the actuator shaft  237  that has one distal end  239  connected to the I/O door  122 . In one embodiment, the distal end  239  is coupled to the I/O door  122  by a spherical bearing, which provides flexibility that allows the I/O door  122  to fully contact the o-ring  136 . During operation, the course of the actuator shaft  237  causes horizontal movements of the I/O door  122  relative to the link shaft  233  to open and close the I/O door  122 . 
         [0028]      FIG. 2C  is a schematic view illustrating horizontal (X directional) movements of the I/O door  122 . In the closed position shown with the dotted lines, a contact surface  277  of the I/O door  122  is urged against a face  276  of the body  132  and tightly contacts the o-ring  136  surrounding the port  123 . The o-ring  136  is secured in a groove  279  on the face  276 . To open the port  123 , the I/O door  122  is moved away from the face  276  in the X direction and out of contact with the o-ring  136 . The vertical actuator blocks (not shown) can thereby operate to lower the I/O door  122  and open the port  123 . Since the I/O door  122  can be moved away from the o-ring  136  when the I/O door  122  is to be lowered by the vertical actuator blocks, the o-ring  136  will not be damaged by the raising/lowering of the I/O door  122 . 
         [0029]    In conjunction with  FIGS. 1A and 1B ,  FIG. 3  is a simplified flow chart illustrating an operation  300  of the load lock chamber  100  according to one embodiment of the present invention. In step  302 , the first actuators  116  are driven by the controller  166  in a synchronous manner when driving the I/O door  122 . In step  304 , the sensors  164  are adapted to detect an exact position of the I/O door  122 . In step  306 , the sensors  164 , after detecting the exact position of the I/O door  122 , returns the position information corresponding to the detected position of the I/O door  122  to the controller  166 . Thereafter, in step  308 , the controller  166  adjusts the moving speed of the first actuators  116  on the basis of the returned position information. If the returned position information is indicative of any misalignment between the first actuators  116  the moving speed of each or both of the first actuators  116  will be adjusted. In doing so, the I/O door  122  could remain substantially parallel to the floor on which the load lock chamber  100  is placed. 
         [0030]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention thus may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.