Abstract:
A transmission box using AMHS for transferring reticle pod is provided, wherein an OHT (Overhead Hoist Transfer) system is disposed on the transmission box to perform mechanical transferring of the reticle pod for greatly reducing risks of damaging reticles caused by operators when transferring, streamlining the allocation of operators, and thus decreasing the time needed for process to complete.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention is related to a transmission box, and more particularly, to a transmission box structure carrying a plurality of reticle pods, the structure of which and of AMHS are used for transferring the plurality of reticle pods. 
         [0003]    2. Description of the Prior Art 
         [0004]    Optical lithography tool plays an important role in the rapidly developing modern semiconductor technology. The pattern definition relies fully on optical lithography technology. In the application of optical lithography tool related to semiconductors, pre-designed circuit paths are fabricated into light-transparent reticles in specific forms. According to the principle of exposure, after light emitted from the light source passes through the reticle and is projected on a silicon wafer, specific circuit pattern can be exposed on the silicon wafer. However, since any kind of dust (such as particles, powders, and organic matters) that adheres to the reticle can result in quality degradation of projected pattern, the reticle used to produce pattern on silicon wafers is required to be kept absolutely clean. Therefore, a cleanroom environment is usually provided in ordinary wafer fabrication processes to prevent from contamination caused by particles in the air. 
         [0005]    In semiconductor process, as the wafer size has progressed to the current 12″ and is still increasing, wafer foundries have set up considerably high standards for automation. By employing computer-integrated manufacturing systems and AMHS, wafer foundries will be able to automatize 100% of its wafer transferring process and also greatly reduce errors caused by manual operation, increase product yield, and streamline factory management. 
         [0006]      FIG. 9  is a view of a reticle pod already in use in semiconductor FAB; the reticle pod comprises: a bottom base a, an upper cover b opposite to the bottom base a, and a supporting piece c located on the bottom base a, wherein the supporting piece c supports a reticle d and the reticle d is enclosed within by the bottom base a and the upper cover b. 
         [0007]    In a typical reticle transferring process, the reticle is placed in a reticle pod, which is a box in airtight status; therefore, the reticle can be protected from contamination of dust particles when it is placed in the reticle pod. Reticle pods are usually transferred manually by operators, who, for example, place a plurality of reticle pods on a cart and the reticle pods on the cart are transferred for the next stage of the process to be performed. However, in current process, the size of reticle has been continually increasing and its weight has also been increasing, and in manual handling and transferring processes, it is inevitable that reticle pods may sometimes drop and serious loss of cost may be caused. Moreover, when the wafer size has progressed to 12″ or beyond, the whole wafer foundry may need to adopt automated systems for its production, and the transferring and handling of reticle pods should also be automatized to catch up with the trend; for example, a safest and fastest way to transfer a reticle pod is using a robot to handle it. 
         [0008]    In view of the concerns mentioned above and to further prevent reticle pods from dropping when being transferred and to fulfill future requirements of wafer foundries for AMHS, provision of a transmission box which is able to safely and efficiently transfer a plurality of reticle pods is thus necessary. 
       SUMMARY OF THE INVENTION 
       [0009]    In order to meet the aforementioned needs, one primary objective of the present invention is to provide a transmission box on which an OHT system with a structure same as that of reticle pod is disposed to co-operate with the AMHS for the transmission box to be mechanically transferred. 
         [0010]    Another primary objective of the present invention is to provide a transmission box that is used for simultaneously transferring a plurality of reticle pods and co-operates with the AMHS for the transmission box to be mechanically transferred; by using such transmission box, risks of possible dropping of reticle pods during manual operation and cost losses can thus be avoided. 
         [0011]    According to the objectives above, the present invention provides a front-opening transmission box, which comprises: a left side, a right side, an upper side, a lower side, a back side, and an opening; a door, the size of which is equivalent to that of the opening of the front-opening transmission box; an OHT (Overhead Hoist Transfer), which is disposed on the upper side of the transmission box; a pair of supporting frames, which are oppositely disposed on the left and right sides of the front-opening transmission box; a plurality of slide grooves, which are collaterally and oppositely formed on the pair of supporting frames and extend from the opening toward the back side; a plurality of first rollers, which are disposed on each of the slide grooves at the end of the opening; a plurality of placing boards, each of which is collaterally disposed on each pair of slide grooves; wherein, the characteristic of the placing boards is in that: each placing board has an upper surface and the upper surface has a plurality of ribs on its edge, and a pair of connection mechanisms corresponding to the slide grooves are disposed on the left and right sides of each placing board, the pair of connection mechanisms having a pair of channels corresponding to the first rollers. 
         [0012]    By adopting the design provided by the present invention, not only can a plurality of reticle pods be transferred at the same time, but the risks of damages caused by manual operation can be greatly reduced, manpower can be saved, and time required for the process to complete can also be decreased. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
           [0014]      FIG. 1  is a view of the front-opening transmission box of the present invention; 
           [0015]      FIG. 2A  is a view of the placing board of the present invention; 
           [0016]      FIG. 2B  is a side view of the placing board of the present invention; 
           [0017]      FIG. 3  is a view of the reticle pod of the present invention placed in the front-opening transmission box; 
           [0018]      FIG. 4A  is a view of the upper side of the front-opening transmission box of the present invention; 
           [0019]      FIG. 4B  is a view of the lower side of the front-opening transmission box of the present invention; 
           [0020]      FIG. 5  is a view of another embodiment of the front-opening transmission box of the present invention; 
           [0021]      FIG. 6  is a view of the center-of-gravity structure of the placing board of the present invention; 
           [0022]      FIG. 7  is a bottom view of the reticle pod of the present invention; 
           [0023]      FIG. 8  is a view of still another embodiment of the front-opening transmission box of the present invention; and 
           [0024]      FIG. 9  is a view of a reticle pod of the prior art. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    As the present invention discloses a front-opening transmission box used in semiconductor fabrication plants, and more particularly, a transmission box for simultaneously transferring a plurality of reticle pods; the positioning devices and OHT employed in the embodiments of front-opening transmission box of the present invention are achieved by using current technologies and the description of which is thus omitted. Moreover, the drawings of the front-opening transmission box referred to in the following description are not made according to the actual scale and only function as illustrations demonstrating characteristics of the present invention. 
         [0026]    First, referring to  FIG. 1 , which is a view of a front-opening transmission box of the present invention. A front-opening transmission box  10 , as shown in  FIG. 1 , comprises: a left side  13 , a right side  14 , an upper side  16 , a lower side  18 , a back side  15 , and an opening  12  opposite to the back side  15 ; a door  20 , the size of which is equivalent to that of the opening  12  of the front-opening transmission box  10 , used for closing the opening  12  of the front-opening transmission box  10 ; a pair of supporting frames  30  snap-fittingly and oppositely disposed on the left side  13  and the right side  14  of the front-opening transmission box  10  and extending from the opening  12  toward the back side  15 , wherein a plurality of corresponding slide grooves  301  are collaterally formed on each of the supporting frames  30  and a first roller  32  is respectively disposed on each of the slide grooves  301  at the end of the opening  12 ; a plurality of placing boards  40 , connection mechanisms  42  on two sides of which are connected with the slide grooves  301  on the supporting frames  30  for allowing the placing boards  40  to slide to and fro on the first rollers  32  on the slide grooves  301 . In addition, the front-opening transmission box  10  is made of wear-resistant polymer material. 
         [0027]    The door  20  of the present invention has a door latch device; a pair of latch devices  22  is disposed on the door  20 , and an oval cam (not shown in the Figure) is used in each latch device  22  to be driven by rotation to push a pair of latches  221 ; the latches  221  slip out of the door  20  into the opposite holes  101  on the upper side  16  and the lower side  18  of the front-opening transmission box  10  for the door  20  to be securely lock-fastened onto the opening  12  of the front-opening transmission box  10 . What is to be emphasized here is that, the latch device  22  can be designed to be operated either by pressing or rotating, and the primary function of which is to join the door  20  with the opening  12  of the front-opening transmission box  10  and keep the door  20  lock-fastened for preventing the door  20  or articles stored inside the transmission box  10  from separating or dropping. The door  20  can be mechanically or manually opened, which is not limited in the present invention. Moreover, what is to be emphasized here is that, the front-opening transmission box of the present invention primarily carries the reticle pod  1 , and yet boxes or articles that are of equivalent size can also be carried, which is not limited in the present invention. 
         [0028]    Then, referring to  FIG. 2A , which is a view of a placing board of the present invention. As shown in  FIG. 2A , the placing board  40  has an upper surface  401 , on the rear end of which is a rib  4011  that protrudes from the upper surface  401 . Moreover, a clipping device  70  is disposed near the front end of the placing board  40 ; the clipping device  70  comprises a base body  71 , which is formed on the upper surface  401  on the front end of the placing board  40 , and a clip  73 , one end of which is pivotally connected to the base body  71  via a pivot  75  and the other end of which is a free end, the clip  73  being thus able to rotate perpendicular to the upper surface  401 . In addition, a protruding portion  731  can be further formed on the clip  73  of the present invention and used for pressing against the reticle pod  1  placed on the upper surface  401  of the placing board  40 . Moreover, in order for the clip  73  to firmly press against the reticle pod  1 , the pivot  75  can be further disposed with an elastic piece  751  (such as a spring) that will be in contact with the clip  73  for increasing the pressing force of the clip  73  against the reticle pod  1 . 
         [0029]    Then, as shown in  FIG. 2B , a pair of connection mechanisms  42  are formed on the two parallel sides of the placing board  40  between its front end and rear end. The pair of connection mechanisms  42  can be connected to the slide grooves  301  on the pair of supporting frames  30  and can be formed in the shape of channel or as an eave portion protruding out of the placing board  40  (not shown in Figure). When the connection mechanisms  42  and the slide grooves  301  on the supporting frames  30  are connected to each other, the connection mechanisms  42  are in contact with the first rollers  32  on the supporting frames  30  so that the placing board  40  can slide to and fro on the first rollers  32  on the slide grooves  301 ; in a preferred embodiment, the connection mechanisms  42  have a pair of channels  421  that correspond to the first rollers  32 , the first rollers  32  being able to roll in the pair of channels  421 . Moreover, in order for the placing board  40  to slide more smoothly, a pair of second rollers  44  can be further disposed on the rear end of the connection mechanisms  42 ; for example, a gap  422  is formed near the rear end of the connection mechanisms  42  and a pair of second rollers  44  are disposed in the gap  422 , as shown in  FIG. 2B . When the reticle pod  1  is placed on the placing board  40 , the reticle pod  1  is prevented from moving in the transferring process with its rear end restricted by the rib  4011  and its front end clamped by the clip  73  of the clipping device  70 . In addition, with the connection mechanisms  42  on two sides of the placing board  40  being connected to the slide grooves  301  of the supporting frames  30 , the placing board  40 , facilitated by the first rollers  32  on the slide grooves  301  or the second rollers  44  on the rear end of the connection mechanisms  42 , is able to slide smoothly on the slide grooves  301  on the supporting frames  30 . 
         [0030]    Referring to  FIG. 3 , which is a view of the reticle pod of the present invention placed on the supporting frames of the front-opening transmission box. As shown in  FIG. 3 , the supporting frames  30  of the present invention are snap-fittingly disposed on the left side  13  and right side  14  of the front-opening transmission box  10  via a plurality of tenons  31  on the supporting frames  30 . Then, as shown in  FIG. 2A , the reticle pod  1  is placed onto the placing board  40  and fastened by the clipping device  70 , and the connection mechanisms  42  on the placing board  40  slide into the slide grooves  301  on the supporting frames  30 ; wherein, the first rollers  32  on the slide grooves  301  will be led into the channels  421  on the connection mechanisms  42 , and the second rollers  44  will also slide into the slide grooves  301  along with the connection mechanisms  42 . Therefore, as the first rollers  32  and the second rollers  44  roll, the placing board  40  can be smoothly drawn. Moreover, an arresting piece  36  is disposed at the rear end of the sliding grooves  301  of the supporting frames  30 . The arresting piece  36  is a protrusive structure and its primary function is as thus: before the placing board  40  completely slides in, the second rollers  44  roll past the arresting piece  36 , and the arresting piece  36 , being a protrusive structure, functions as a stop structure that prevents the placing board  40  from sliding out after the second rollers  44  roll past the arresting piece  36  (just as a brick set under a wheel to prevent the wheel from rolling); 
         [0031]    when the placing board  40  slides past the arresting piece  36 , it can be ensured that the placing board  40  is completely placed in the transmission box and thus incomplete placement of the placing board  40  can also be avoided. 
         [0032]    Then, referring to  FIG. 4A , which is an upper side of the front-opening transmission box of the present invention. As shown in  FIG. 4A , an OHT (Overhead Hoist Transfer)  50  is disposed on the upper side  16  of the front-opening transmission box  10 , the OHT  50  is a rectangular protruding board with protruding periphery  501 . In 12-inch wafer foundries, FOUP is mainly used for transferring wafers. As FOUP that is used to transfer wafers is of certain weight and cannot be easily carried manually by operators, AMHS is usually adopted in the process of handling FOUP and robots are used to clasp the protruding periphery of OHT  50  for transferring FOUP to platforms (such as a Load Port). And the protruding periphery  501  of the OHT  50  disposed on the upper side  16  of the front-opening transmission box  10  of the present invention also functions in a similar way: protruding periphery  501  of the same size and shape can be disposed for being clasped by a same robot, and, the OHT  50  can also be replaced with OHT  50  of different sizes and shapes to correspond to and co-operate with different machines; therefore, the size and shape of OHT  50  is not limited in the present invention, as long as its size and shape allow it to be clasped by robots. And the OHT  50  is either screw-locked on or tenon-fitted to the upper side  16  of the front-opening transmission box  10 , the way of which is not limited in the present invention. 
         [0033]    Then, referring to  FIG. 4B , which is a view of the lower side of the front-opening transmission box of the present invention. As shown in  FIG. 4B , the lower side  18  of the front-opening transmission box  10  is disposed with three, or a multiple of three, positioning grooves  60 , each of which is a device with a cavity, and the positioning grooves  60  are deployed in a triangular disposition on the lower side  18 . In wafer foundries, robots clasp a FOUP/transmission box  10  and carry it to a platform, on which are a plurality of positioning bolts (not shown in Figure) that correspond to the positioning grooves  60  on the bottom surface of the FOUP/transmission box  10 ; therefore, when the FOUP/transmission box  10  is placed on the platform, the positioning bolts on the platform insert into the positioning grooves  60  for the front-opening transmission box  10  to be securely placed on the platform. 
         [0034]    Referring to  FIG. 5 , which is a view of another embodiment of front-opening transmission box of the present invention. As shown in  FIG. 5 , since the back side  15  of the front-opening transmission box  10  does not necessarily intersect the left side  13  and the right side  14  at right angles (may intersect in curves or recesses for example), therefore, when the reticle pods to be carried are larger ones (such as EUV pods), there may not be enough space in the front-opening transmission box  10 . Thus, in the present embodiment, the joint surface between the back side  15  of the front-opening transmission box  10  and its left side  13  and right side  14  can be designed as a hollowed-out structure  80 , the design of which allows a portion of an EUV pod to protrude out of the front-opening transmission box  10  and facilitates the placement of the whole EUV pod. In a preferred embodiment, the hollowed-out structure  80  can be disposed on the left side  13  and the right side  14  and close to the back side  15 ; moreover, the hollowed-out structure  80  can be multiple hollowed-out structures  80  arranged at intervals or one long-shaped hollowed-out structure  80 , which is not limited in the present invention. Other details of the embodiment are the same as what are described above and are hereby omitted. 
         [0035]    Then, referring to  FIG. 6 , which is a view of the center-of-gravity structure of the placing board of the present invention. As shown in  FIG. 6 , at least a weight allocating structure  46  is further disposed on the surface of the placing board  40  of the present invention, the position of the weight allocating structure  46  being not limited and the weight allocating structure  46  being primarily made of metal. The objective of disposing a weight allocating structure  46  on the placing board  40  is mainly as thus: when the upper side  16  of the front-opening transmission box  10  is disposed with an OHT  50 , the center of gravity of the box will shift forward and the transmission box will become unstable when it is suspended by the robot, and a weight allocating structure  46  is thus disposed on the placing board  40  to balance the center of gravity of the box so that the transmission box can be stably transferred in suspension. Moreover, the upper surface  401  of the placing board  40  is disposed with a plurality of foolproof structures  4013 , which are deployed in triangular disposition in the present invention but is not limited. Then, as shown in  FIG. 7 , a plurality of foolproof notches  5  are disposed beneath the base board  3  of the reticle pod  1 , each of the foolproof notches  5  corresponding to each of the foolproof structures  4013  on the upper surface  401  of the placing board  40 ; therefore, when being placed on the placing board  40 , the reticle pod  1  needs to be aligned according to the foolproof structures  4013  due to the triangular disposition of the foolproof structures  4013 , i.e. the foolproof notches  5  need to correspond to the foolproof structures  4013 . The primary function of the foolproof structures  4013  is to prevent the reticle pod  1  from being placed in wrong directions and also to standardize the way of placement to facilitate the process. 
         [0036]    Referring then to  FIG. 8 , which is a view of still another embodiment of the front-opening transmission box of the present invention. The front-opening transmission box  10 , as shown in  FIG. 8 , comprises: a left side  13 , a right side  14 , an upper side  16 , a lower side  18 , a back side  15 , and an opening  12  opposite to the back side  15 ; a door  20 , the size of which is equivalent to that of the opening  12  of the front-opening transmission box  10 , used for closing the opening  12  of the front-opening transmission box  10 ; a plurality of supporting ribs  48  correspondingly disposed on the inner sides of the left side  13  and the right side  14  of the front-opening transmission box  10 , each supporting rib  48  extending from the opening  12  toward the back side  15 ; a plurality of placing boards  40 , placed on a corresponding pair of supporting ribs  48 ; a plurality of buckles  90  respectively disposed on one end of each of the placing boards  40  at the opening  12 , one end of each buckle  90  being pivotally connected to a fixing pin  92 , each fixing pin  92  fastening each buckle  90  to each placing board  40  and allowing each buckle  90  to swing out of and into the opening  12 ; similarly, the fixing pin  92  can be further disposed with an elastic piece such as a spring (not shown in Figure), and the elastic piece can be disposed inside the buckle  90  for increasing the pressing force of the buckle  90 . 
         [0037]    The way of operation of the present embodiment is described in the following. When the reticle pod  1  is placed on the placing board  40 , the buckles  90  on the placing board  40  at the opening  12  clasp the reticle pod  1 , and the connection mechanisms  42  on the placing board  40  that carries the reticle pod  1  are aligned with the corresponding supporting ribs  48  disposed on the left side  13  and the right side  14  of the front-opening transmission box  10  for the placing board  40  to enter the front-opening transmission box  10 ; finally, the door  20  is used to close the opening  12  of the front-opening transmission box  10 . 
         [0038]    Apparently, in the front-opening transmission box  10  of the present embodiment, a plurality of supporting ribs  48  are used to substitute the supporting frames  30  so that the placing boards  40  can be directly placed on the supporting ribs  48 , the supporting ribs  48  forming a plurality of spaces for accommodating reticle pods in the front-opening transmission box  10 ; moreover, buckles  90  are used to substitute clipping devices  70 . Except for these, the front-opening transmission box  10  and the placing boards  40  are similar to those described in  FIG. 1  and  FIG. 2A  and  FIG. 2B , and the differences are previously described and are herein omitted. 
         [0039]    Although the present invention has been described with reference to the aforementioned preferred embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.