Abstract:
An exemplary wet coating system includes a coating chamber, an annealing chamber, an unloading chamber, and a mechanical arm. The coating chamber is configured for allowing a substrate being wet coated therein. The unloading chamber is configured for allowing the substrate being unloaded therein. The annealing chamber is interposed between and communicated with the coating chamber and the unloading chamber and is configured for allowing the substrate being annealed therein. The communicated coating chamber, annealing chamber, and unloading chamber are vacuumized. The mechanical arm is configured for holding the substrate and moving the substrate across the coating chamber, the annealing chamber, and the unloading chamber.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    This present disclosure relates to wet coating technologies and, particularly, to a wet coating system for forming a thin film on a substrate. The wet coating system is capable of avoiding or at least reducing oxidization of the thin film during the transportation of the substrate film from a coating solution to an annealing chamber. 
         [0003]    2. Description of Related Art 
         [0004]    Generally, a thin film can be formed on a substrate by wet coating. In the process of wet coating, the substrate is firstly dipped into a coating solution and then is transported to an annealing chamber. In the annealing chamber, the substrate is annealed so that the thin film can achieve certain performances. However, during the transportation of the substrate, the substrate is exposed to the air and therefore the thin film may be oxidized. This may adversely effect the performance of the thin film. 
         [0005]    Therefore, it is desirable to provide a wet coating system, which can overcome the above-mentioned problems. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a schematic view of a wet coating system, according to a first exemplary embodiment. 
           [0007]      FIG. 2  is an isometric, schematic view of a substrate holding unit of the wet coating system, according to a first exemplary embodiment. 
           [0008]      FIG. 3  is an isomeric, schematic view of a substrate holding unit of the wet coating system, according to a second exemplary embodiment. 
           [0009]      FIG. 4  is a partially cross-sectioned view taken along a line IV-IV of  FIG. 3 . 
           [0010]      FIG. 5  is an isomeric, schematic view of a substrate holding unit of the wet coating system, according to a third exemplary embodiment. 
           [0011]      FIG. 6  is a cross-sectioned view taken along a line VI-VI of  FIG. 5 . 
           [0012]      FIG. 7  is an isomeric, schematic view of a substrate holding unit of the wet coating system, according to a fourth exemplary embodiment. 
           [0013]      FIG. 8  is a cross-sectioned view taken along a line VIII-VIII of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Referring to  FIG. 1 , a wet coating system  70 , according to an exemplary embodiment, includes a coating chamber  71 , an annealing chamber  72 , an unloading chamber  73 , an access door  74 , two automatic doors  75 , and a mechanical arm  77 . 
         [0015]    The annealing chamber  72  is interposed between the coating chamber  71  and the unloading chamber  73 . One of the two automatic doors  75  is interposed between the coating chamber  71  and the annealing chamber  72  and configured for closing an entrance (not labeled) from the coating chamber  71  to the annealing chamber  72 . The other automatic door  75  is interposed between the annealing chamber  72  and the unloading chamber  73  and configured for closing an entrance (not labeled) from the annealing chamber  72  to the unloading chamber  73 . The access door  74  is disposed on the unloading chamber  73  and configured for closing an entrance (not labeled) from outside to the unloading chamber  73 . Before the process of wet coating, a number of substrates  101  are loaded in the coating chamber  71  (see below). Then, the access door  74  is closed and the two automatic doors  75  are opened, the coating chamber  71 , the annealing chamber  72 , and the unloading chamber  73  communicate with each other and are vacuumized to form a closed vacuum space. 
         [0016]    The mechanical arm  77  is configured for holding and transporting the substrates  101  among the coating chamber  71 , the annealing chamber  72 , and the unloading chamber  73 . The wet coating system  70  may further include a controller  76 . The controller  76  is configured for coordinating the mechanical arm  77  and the automatic doors  75  so that the automatic doors  75  are kept closed but opened when the mechanical arm  77  moves across a corresponding entrance between the coating chamber  71  and the annealing chamber  72  or between the annealing chamber  72  and the unloading chamber  73 . 
         [0017]    In the coating chamber  71 , the wet coating system  70  further includes a reacting room  103 , a number of containers  104  placed in the reacting room  103  and filled with a coating solution  102 , and a substrate holding unit  100  suspended above the reacting room  103  and movable down towards the containers  104  or up away from the containers  104 . The substrate holding unit  100  is configured for holding a number of substrates  101  and moving into the corresponding containers  104  to dip the substrates  101  in the coating solution  102 . The coating solution  102  is configured for liquidly depositing a thin film (not shown) on the substrates  101 . 
         [0018]    Also referring to  FIG. 2 , in this embodiment, the substrate holding unit  100  includes six holding members  11 , a main body  12 , and a connecting arm  13  and is capable of holding six substrates  101  simultaneously. 
         [0019]    The main body  12  is for supporting the holding members  11  and is a hexagonal cylinder in shape. In detail, the main body  12  includes a regular hexagon top surface  121  and a regular hexagon bottom surface  125 , and six rectangular side surfaces  123  connecting the top surface  121  and the bottom surface  125 . The connecting arms  13  radially extend outwards from corresponding side surfaces  123 . 
         [0020]    Each of the holding members  11  includes a suspending arm  110  and a clamper  113 . The suspending arm  110  is a circular cylinder in shape and includes an upper end surface  110   a , a lower end surface  110   b , and a cylindrical side surface  110   c  connecting the upper end surface  110   a  to the lower end surface  110   b . Each of the clampers  113  is structured and mechanized to fittingly clamp one substrate  101  and is connected to one end of the suspend arm  110  corresponding to the lower end surface  110   b . The other end of the suspending arm  110  corresponding to the upper end surface  110   a  is connected to a corresponding connecting arm  13 . 
         [0021]    In other alternative embodiments, the main body  12  is not limited to be a hexagonal cylinder, but can be other appropriate shapes, such as, a cube or a circular cylinder. The number of the connecting arms  13  and the holding members  11  are also not limited to six, but can be other numbers. 
         [0022]    To monitor the process of depositing film on the substrates  101 , the wet coating system  70  can further include six monitors  15 . Each of the monitors  15  can be installed on a corresponding upper end surface  110   a  and is configured for monitoring the dipping depth, the dipping time and other film depositing parameters of a corresponding substrate  101 . To realize various measurements of the deposition parameters, each of the monitors  15  can include a sensor  1131 . Practically, the sensor  1131  is installed in a vicinity of the substrate  101 . Therefore, in this embodiment, the sensor  1131  is attached to the clamper  113 . 
         [0023]    Typically, the coating solution  102  is volatilizable. Volatilization gases from one type of coating solution  102  can mix with other kinds of volatilization gases when more than one type of coating solution  102  is employed. This may reduce the purity of each type of coating solution  102 . Therefore, to avoid the reduction of the purity of each type of coating solution, the wet coating system  70  further includes a gas introducing unit  710  and a gas expelling unit  711 . The gas introducing unit  710  is configured for introducing noble gas (not shown), e.g., nitrogen, into the coating chamber  71 . The noble gas can reduce the density of the volatilization gases of the coating solution  102 . This can reduce the effect of the different volatilization gases mixing. The gas expelling unit  711  is configured for expelling the introduced noble gas and the volatilization gases of the coating solution  102  from the coating chamber  71 . This can further reduce the effect of mixing of the different volatilization gases. 
         [0024]    To facilitate discharging the coating solution  102  into the containers  104  and removing the coating solution  102  from the containers  104 , the wet coating system  70  further includes an inlet pipe  714 , an inlet valve  7140  installed on the inlet pipe  714  to control the flow of the coating solution  102  flowing in the inlet pipe  714 , a number of inlet branches  7141  each of which communicates the inlet pipe  714  with a corresponding container  104 , a number of discharging branches  7031  each of which communicates a corresponding container  104  to discharge the coating solution  102  from the corresponding container  104 , an outlet pipe  713  which communicates the discharging branches  7131  to collect the coating solution  102  of all the discharging branches  7131 , and an outlet valve  7130  installed on the outlet pipe  713  to control the flow of the coating solution  102  flowing in the outlet pipe  713 . Practically, each of the charging branches  7141  is connected to the top of the corresponding container  104 . Each of the discharging branches  7131  is connected to the bottom of the corresponding container  104 . 
         [0025]    In the annealing chamber  72 , the wet coating system  70  includes a heating member  721 . The heating member  721  is used to heat the substrates  101  with the thin film, so that the adhesion of the thin film is increased. In this embodiment, the heating member  721  can heat the substrate  101  to 400˜500 and remain the temperature of the substrate  101  around 400˜500 for a predetermined time. To realize this heating process, the wet coating system  70  may further includes a temperature sensor  723  and a heating controller  725 . The temperature sensor  723  is configured for sensing the temperature of the heating member  721  and feedbacks the sensed temperature to the heating controller  725  so that the heating controller  725  can properly control the heat member  721  to work. 
         [0026]    The unloading chamber  73  is configured for unloading the substrates  101 . Practically, after a substrate  101  has been heated, the substrate  101  is transported to the unloading chamber  73  by the mechanical arm  77  to allow the substrate  101  to naturally and slowly cool down. After the substrate  101  has cooled down, the process of annealing is finished and the substrate  101  can be unloaded by the mechanical arm  77  and taken out of the unloading chamber  73  via the access door  74 . 
         [0027]    Referring to  FIGS. 3-4 , a second substrate holding unit  200 , according to a second exemplary embodiment, is substantially similar to the substrate holding unit  100  but further includes a driving member  212  for driving the clamper  113  to move down into or up away from the coating solution  102 . Also, to accommodate the newly added driving member  212 , a suspending arm  210  of this embodiment is different from the suspending arm  210  too. The suspending arm  210  is a hollow circular cylinder in shape and includes an inner top surface  2101  and defines a first threaded section  2108  in the inner cylindrical surface thereof. The driving member  212  includes a motor  2100  and a transmission rod  2123 . The motor  2100  is fixed to the inner top surface  2101  generally at the center thereof and includes a shaft  2102  with a second threaded section  2104  formed on the outer surface thereof. The transmission rod  2123  is a circular cylinder and has a diameter slightly less than the inner diameter of the suspending arm  210 . The transmission rod  2123  defines a third threaded section  2121  corresponding to the first threaded section  2108  in the outer cylindrical surface thereof, a blind hole  2120  along the central axis thereof, and a fourth threaded section  2122  corresponding to the second threaded section  2104  in the inner surface of the bind hole  2120 . 
         [0028]    The transmission rod  2123  is coupled to the shaft  2102  via the second threaded section  2104  and the fourth threaded section  2122  and is coupled to the suspending arm  110  via the first threaded section  2108  and the third threaded section  2121 . The motor  2100  is electrically connected to the monitor  15 . The monitor  15  is further configured for controlling the motor  2100  based upon monitored deposition parameters of the substrates  101 . When the movement of the substrates  101  is required, the motor  2100  rotates under control of the monitor  15 . As such, the transmission rod  2123  is driven to move up or down. 
         [0029]    Referring to  FIGS. 5-6 , a third substrate holding unit  300 , according to a third embodiment, is substantially similar to the substrate holding unit  100 . However, in this embodiment, a main body  32 , six connecting arms  33 , and six suspending arms  310  are all hollow, and the inner space (not shown) of the main body  32  communicates with the inner spaces of the connecting arms  33  which in turn communicate with the inner spaces of the suspending arms  310 . A top surface  321  of the main body  32  further defines an inlet  3210  communicating with the inner space of the main body  32 . Each of the suspending arms  310  defines a number of outlets  311  communicating with the inner space of the suspending arms  310 . The outlets  311  face the clamper  113 . The substrate holding unit  300  further includes a blower  36 . The blower  36  faces the inlet  3210  and is configured to blow a gas through the inlet  3210  to the outlets  311 , and to the substrates  101  after the substrates  101  are drawn up away from the coating solution  102  to speed the air-drying of the coating solution  102  adhered to the substrates  101 . Practically, the blower  36  can blow noble gas to the substrate  101  to avoid reactions with the coating solution  102  occurring. 
         [0030]    Referring to  FIGS. 7-8 , a fourth substrate holding unit  400 , according to a fourth exemplary embodiment, is substantially similar to the substrate holding unit  300  but further employs the driving unit  212 . Therefore, a suspending arm  410  of this embodiment is similar to the suspending arm  210  but further defines the outlets  311 . 
         [0031]    While various exemplary and preferred embodiments have been described, it is to be understood that the disclosure is not limited thereto. To the contrary, various modifications and similar arrangements (as would be apparent to those skilled in the art) are intended to also be covered. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.