Abstract:
A reticle pod with drain structure comprises an outer container and an inner container, wherein an upper cover of inner container is disposed with a plurality of retainers, and a plurality of supporters disposed on the outer container are used to press the retainers for fastening and stabilizing the reticle in the inner container and thus ensuring safety and stability of the reticle in the reticle pod. Collision risks of the reticle in the reticle pod due to vacillation of reticle pod during transportation can be reduced. Cost of reticles also can be greatly decreased. Further, a plurality of drain holes is disposed on a lower cover of the outer container for draining the remained water in the outer container. It will be done without disassembling the lower cover of outer container for reducing the contamination opportunity in the pod and preventing from wasting of labor and time for disassembling.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims priority to Taiwan Patent Application No. 100101022, filed Jan. 11, 2011, the contents of which are hereby incorporated by reference in their entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a reticle pod, and more particularly, to a reticle pod with drain structure. 
     2. Description of the Prior Art 
     In the rapidly developing modern semiconductor technology, optical lithography technique plays an important role. The pattern definition relies fully upon optical lithography technique. In the application of optical lithography technique related to semiconductors, pre-designed circuit layouts are fabricated as light-transparent reticle in specific form. Basing on the principle of exposure, after light from the light source passes through the reticle and is projected on a silicon wafer, a specific circuit pattern can be exposed on the silicon wafer. However, since any kind of dust (such as particles, powders, and organic matters) that adhere 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. 
     Recently, in order to further scale down the chip feature sizes, EUV (extreme ultraviolet light) at a wavelength of 157 nm is applied in lithography apparatus for the pattern on reticle to be imaged with higher resolution when being projected on the surface of a silicon wafer. However, when EUV is applied, the requirements for cleanliness of reticle pod are also, relatively speaking, higher. Particles smaller than 30 μm are previously acceptable, but as far as reticle pods for use with EUV lithography techniques are concerned, only particles with sizes between 30 and 50 nm are acceptable. 
     As a result, anti-contamination reticle pods are used in modern semiconductor process to store and carry reticles and to maintain the cleanliness of reticles; on the other hand, anti-contamination storage containers for semiconductor components are also used for storing and carrying semiconductor components and also for maintaining the cleanliness of semiconductor components. Reticle pods are used in the semiconductor process for storing reticles and for facilitating the carrying and transporting of reticles between platforms in order to isolate reticles from the air and thus prevent haze from forming on the surface of reticles due to contamination of reticles caused by particles and chemical gas. Thus, in advanced semiconductor plants, the cleanliness of reticle pods or storage devices for semiconductor components is usually required to comply with the SMIF (Standard Mechanical Interface) standard, in other words, to be maintained at Class 1 or below. 
     In order to reduce contamination generated during the process of storing, manufacturing, and transporting, a technology that uses a double-layer container for isolating the reticle has been proposed in the prior art, wherein an inner container is used for carrying the reticle and an outer container is used for fastening the inner container therein. As shown in  FIG. 8 , the lower cover c and the upper cover d of an inner container cover the reticle e and fasten the reticle e within the inner container, and then the lower cover a and the upper cover b of an outer container cover the inner container and fasten the inner container within the outer container. In the double-layer pod structure, supporters disposed in an outer container are usually used for fastening the inner container. However, in such double-layer pod structure, the user is unable to determine whether the inner container is stably snap-fastened by the supporters of the outer container and is unable to make sure the positioning status of the reticle in the inner container either. In consideration of the aforementioned, the present invention provides a reticle pod in which supporters of the outer container are used to press retainers of the inner container and thus indirectly fasten the reticle inside for ensuring safety and stability of the reticle in the reticle pod. 
     Besides, during cleaning, the conventional pod has no design to drain the remained water in the bottom side. Thereby, the remained water in the conventional pod under cleaning cannot be removed easily, and the water spot or other contaminations will be remained in the conventional pod. Accordingly, the contamination chance of the reticle will be increased. 
     SUMMARY OF THE INVENTION 
     In order to solve the above-mentioned problem, one primary object of the present invention is to provide a reticle pod with a drain structure, in which the remained water is removed directly from the drain holes on the outer container during cleaning the reticle pod without disassembling the outer container. Therefore, the contamination chance of the reticle will be reduced efficiently as well as the wasting of labor and time can be prevented from. 
     Another primary object of the present invention is to provide a reticle pod with a drain structure, in which a centrifugal force is generated to accelerate the draining of the remained water, and the remained water in the reticle pod is drained by the drain holes. 
     Another primary object of the present invention is to provide a reticle pod with a drain structure, in which supporters disposed on the outer container are used to press retainers of the inner container for indirectly fastening reticle inside the pod and thus ensuring the safety and stability of the reticle inside. 
     Another primary object of the present invention is to provide a reticle pod with a drain structure, in which supporters disposed on the outer container are used to press retainers of the inner container for preventing the inner container from shifting and further ensuring the safety of the reticle inside the inner container. 
     According to the objectives above, the present invention provides a reticle pod with a drain structure, comprising: an outer container, comprising: and a lower cover of outer container, having a first inner surface and four sides connected with said first inner surface, a plurality of first supporters being formed on said first inner surface, a plurality of drain holes disposed on the lower cover of outer container; an upper cover of outer container, having a second inner surface, a plurality of second supporters being formed on said second inner surface, said first inner surface and said second inner surface forming a first accommodation space when said lower cover of outer container and said upper cover of outer container are joined together; and an inner container comprising: a lower cover of inner container, being disposed in said first accommodation space and being in contact with said first supporters, said lower cover of inner container having a first inner surface of inner container; and an upper cover of inner container, being in said first accommodation space and having a second inner surface of inner container and an outer surface of upper cover of inner container which is on opposite side of said second inner surface of inner container, said first inner surface of inner container and said second inner surface of inner container forming a second accommodation space for accommodating a reticle when said lower cover of inner container and said upper cover of inner container are joined together; a plurality of through holes, being formed between said second inner surface of inner container and said outer surface of upper cover of inner container; and a plurality of retainers, being respectively disposed in said plurality of through holes, the position of each of said plurality of retainers corresponding to each of said second supporters of said upper cover of outer container. 
     According to the object above, the present invention provides a reticle pod with a drain structure, comprising: an outer container, comprising: a lower cover of outer container, said lower cover of outer container having a first inner surface and four sides that are joined with said first inner surface, a plurality of drain holes being disposed on said lower cover of outer container; and an upper cover of outer container having a second inner surface, said first inner surface and said second inner surface forming a first accommodation space for accommodating a reticle when said lower cover of outer container and said upper cover of outer container are joined together. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an explosive view of the reticle pod of the present invention; 
         FIG. 2  is a view of the retainer of the upper cover of inner container of the present invention; 
         FIG. 3  is a view of the filter device of the upper cover of inner container of the present invention; 
         FIG. 4  is a view of the foolproof structure of the upper cover of inner container of the present invention; 
         FIG. 5  is a view of the limiter of the lower cover of inner container of the present invention; 
         FIG. 6  is a view of the window of the lower cover of inner container of the present invention; 
         FIG. 7  is a sectional view of the reticle pod of the present invention; 
         FIG. 8  is a view of the reticle pod of the prior art. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As the present invention discloses a reticle pod, and more particularly, a reticle pod with a draining structure; the inner container, outer container, and the filtering material employed in the embodiments of reticle pod of the present invention are achieved by using current technologies and the description of which is thus omitted. Moreover, the drawings referred to in the following description are not made according to the actual scale and only function as illustrations demonstrating characteristics of the present inventions. 
     First, referring to  FIG. 1 , which is an explosive view of the reticle pod of the present invention. As shown in  FIG. 1 , the reticle pod comprises an outer container  1  and an inner container  2 , wherein the outer container  1  comprises a lower cover of outer container  10  having a first inner surface  101  with a plurality of first supporters  30 , and an upper cover of outer container  12  having a second inner surface  121  with a plurality of protruding second supporters  32 , a first accommodation space  100  being formed between the first inner surface  101  of the lower cover of outer container  10  and the second inner surface  121  of the upper cover of outer container  12  for accommodating and fastening the inner container  2  when the lower cover of outer container  10  and the upper cover of outer container  12  are joined together. The inner container  2  comprises a lower cover of inner container  20  having a first inner surface of inner container  201  and an outer surface of lower cover of inner container  203  opposite to the first inner surface of inner container  201 , the outer surface of lower cover of inner container  203  contacts the plurality of first supporters  30 . An upper cover of inner container  22  has a second inner surface of inner container  221  and an outer surface of upper cover of inner container  223  opposite to the second inner surface of inner container  221 , a second accommodation space  200  being formed between the first inner surface of inner container  201  and the second inner surface of inner container  221  for accommodating a reticle  9  when the lower cover of inner container  20  and the upper cover of inner container  22  are joined together. 
     Furthermore, in the embodiment, four sides of the lower cover of outer container  10  are disposed with a plurality of drain holes  105 , which are shown as round holes in  FIG. 1 ; and a pair of lock holes  103 , which are shown as rectangular holes in  FIG. 1 , are further disposed on two opposite sides  102  among four sides of the lower cover of outer container  10 . Apparently, as the lower cover of outer container  10  is disposed with a latch (not shown in Figure), when the latch is turned to close the outer container, the latch projects into the lock holes  103 . An objective of disposing a plurality of drain holes  105  is as thus: after the lower cover of outer container  10  of the reticle pod of the present invention is cleaned with water, water molecules remaining in the lower cover of outer container  10  can be directly drained out through the plurality of drain holes  105  without disassembling the lower cover of outer container  10  after heating and baking processes are performed. Thereby, it will prevent from the wasting of the labor and time for disassembling the lower cover of outer container  10  and decrease the contamination chance in the reticle pod. 
     Furthermore, the disposition locations of the drain holes  105  in the embodiment are corresponding to the tangent direction of rotation generated under cleaning of the reticle pod. The reticle pod is disposed on a conventional rotatable washing machine during cleaning the reticle pod. Before the cleaning of the reticle pod is performed, the lower cover of outer container  10  is lay on a surface of a washing machine corresponding to and opposite to the first inner surface  101  of the lower cover of outer container  10 . The washing machine carries the reticle pod to rotate and thus to generate a centrifuge force under rotation. The drain holes  105  in the embodiment are arranged on sides  102  of the lower cover of outer container  10 , that is, the disposition locations of the drain holes  105  are located on the tangent direction of rotation of the reticle pod. Therefore, the centrifuge force carries the remained water in the lower cover of outer container  10  to drain out through the drain holes  105  located on the tangent direction of rotation. It will accelerate to drain out the remained water molecules in the lower cover of outer container  10 . 
     Then, referring to  FIG. 2 , which is a view of the retainer of the upper cover of inner container of the present invention. As shown in  FIG. 2 , a plurality of through holes  225  are disposed between the second inner surface of inner container  221  and the outer surface of upper cover of inner container  223 ; in addition, an O-shaped recess  2251  is formed as surrounding each of the through holes  225  and is disposed with a spring element  42 . Moreover, a retainer  40  is disposed in each of the through holes  225 . The retainer  40  is formed by a supporting convex pillar  401  with a size fitting for being inserted into a through hole  225  and an O-shaped protruding portion  403  correspondingly disposed in the O-shaped recess  2251 ; the supporting convex pillar  401  and the O-shaped protruding portion  403  are an integrated structure; wherein, the supporting convex pillar  401  is inserted into the through hole  225 , and the O-shaped protruding portion  403  is in the O-shaped recess  2251  and the protruding portion  4031  of the O-shaped protruding portion  403  is in contact with the spring element  42 ; apparently, the length of the supporting convex pillar  401  of the retainer  40  is larger than that of the protruding portion  4031  of the O-shaped protruding portion  403 . Additionally, the position of each retainer  40  corresponds to each second supporter  32  of the upper cover of outer container  12 . Furthermore, on each retainer  40  on the outer surface of upper cover of inner container  223 , a plurality of first fasteners  44  that fastens the retainers  40  are disposed, the first fasteners  44  respectively cover a plurality of through holes  225  to fastens each of the retainers  40  for corresponding to the through holes  225 . Each of the first fasteners  44  having a hole  441  with a size smaller than the retainer  40  so that part of the surface of the retainer  40  can be exposed; therefore, with the O-shaped recess  2251  and the first fastener  44  being joined together, the retainer  40  can be fastened and prevented from dropping down. Moreover, the first fastener  44  of the present invention is lock-fastened to the inner container  2  for storing the reticle with a screw and can also be disposed in the inner container  2  for storing the reticle either via being snap-fitted or adhered to the inner container  2 , the way of which is not limited in the present invention. And the material of retainer  40  is a wear-resistant polymer material so that friction that may generate particles and dusts which contaminate the reticle  9  in the inner container  2  can be prevented. 
     Referring then to  FIG. 3 , which is a view of filter device of the upper cover of inner container of the present invention. As shown in  FIG. 3 , at least a filtration hole  227  is formed on the outer surface of upper cover of inner container  223 , and at least a filtration. device  5  is arranged on the filtration hole  227 , in which the filtration device  5  includes a filter material  50  and a second retainer  52 . The filter material  50  is disposed on each filtration hole  227 . The filter material  50  of the present invention can be a porous filter membrane and can be selected from the group consisting of: glass-fiber filter, static electricity filter, electrically conductive filter membrane, PTFE filter, and porous ceramic material, which is not limited in the present invention. Moreover, a second retainer  52  can be further disposed on the filtration hole  227  to reinforce the fastening; the second retainer  52  can be lock-fastened to the outer surface of upper cover of inner container  223  via a screw or in other ways, the way of lock-fastening the second retainer  52  is not limited in the present invention. In a preferred embodiment of the present invention, two filtration holes form a set and the upper cover of inner container  22  is disposed with two sets of filtration holes  227 , and yet the actual number of filtration holes  227  disposed is not limited in the present invention. 
     And then, referring to  FIG. 4 , which is a view of foolproof structure of the upper cover of inner container of the present invention. As shown in  FIG. 4 , an integrated foolproof structure  60  is respectively formed on four corners arranged on the upper cover periphery  222  of the upper cover of inner container  22 . The characteristic is in that a portion of the foolproof structure  60  of the present invention will protrude from the upper cover periphery  222  of the upper cover of inner container  22 , and thus, when the upper cover of inner container  22  and the lower cover of inner container  20  are joined together, the protruding portion of the foolproof structure  60  will be snap-fitted on the lower cover periphery  202  of the lower cover of inner container  20 ; since the foolproof structure  60  is respectively formed on the four corners, when the inner container  2  is closed, the upper cover  22  and the lower cover  20  are successfully joined only when all the foolproof structures  60  on four corners are snap-fitted, the foolproof effect being thus achieved. Moreover, as the length and the width of the inner container  2  are not the same, the length-to-width ratio can also be taken into consideration when the inner container  2  is closed for determining whether the closing of inner container  2  is correctly performed. 
     Referring then to  FIG. 5 , which is a view of the limiter of lower cover of inner container of the present invention. As shown in  FIG. 5 , each of the four corners of the first inner surface of inner container  201  of the lower cover of inner container  20  has a recess  204 , in which a limiter  70  is respectively disposed; the limiter  70  is a horizontal bar-shaped substrate  701  with two convex columns  703  disposed on two sides, and a bevel  704  is respectively formed at the open end of each of the convex columns  703 ; a supporting protruding point  705  is further disposed between the two convex columns  703  of the horizontal bar-shaped substrate  701 , and the supporting protruding point  705  and the two convex columns  703  are disposed on a straight line. When the limiter  70  is disposed in the recess  204  of the first inner surface of inner container  201 , the top surface of the horizontal bar-shaped substrate  701  of the limiter  70  and the first inner surface of inner container  201  will be on the same horizontal level. When the reticle  9  is to be placed onto the first inner surface of inner container  201 , if the reticle  9  shifts its position, the reticle  9  can be guided to the correct position by the bevels  704  of the convex columns  703  and each of the four corners of the reticle  9  is in contact with the supporting protruding point  705  on the horizontal bar-shaped substrate  701 ; the reticle  9  is thus placed onto the first inner surface of inner container  201 . 
     Moreover, the pair of convex columns  703  on each limiter  70  can serve as identification devices on the robot to identify reference point for reticle alignment so that the robot can accurately grip the reticle. Furthermore, in addition to being disposed at four corners of the first inner surface of inner container  201 , each limiter  70  of the present invention can be alternatively disposed on the point of intersection at 146 mm on each side of the first inner surface of inner container  201 ; therefore, the position of each limiter  70  on the first inner surface of inner container  201  is not limited in the present invention as long as the position of each limiter  70  is on or beyond the point of intersection at 146 mm on each side of the first inner surface of inner container  201 , such design ensuring that the supporting protruding point  705  of each limiter  70  is only in contact with the edge of the reticle and does not cause wear of or damage to pattern on the reticle. 
     Then, referring to  FIG. 6 , which is a view of the window of the lower cover of inner container of the present invention. As shown in  FIG. 6 , a plurality of windows  205  are disposed on the outer surface of lower cover of inner container  203  which is on the opposite side of the first inner surface of inner container  201 , and a transparent substrate  80  made of transparent glass, transparent plastic material, or other materials is respectively disposed in each of the windows  205 ; on the transparent substrate  80 , a third fastener  82  is disposed on the outer surface of lower cover of inner container  203  of the lower cover of inner container  20  to cover the windows  205 , and further disposed for snap-fitting the transparent substrate  80  to the window  205  and prevent the transparent substrate  80  from dropping down. The third fastener  82  is a frame-shaped member with a size fitting to the window, and thus the reticle inside can be monitored from outside the lower cover of inner container  20  via the window  205 . Therefore, during the process, there will be signals from platforms to inspect the process and function of a reticle via the window  205 . Moreover, a ring-shaped pad  84  is disposed between the transparent substrate  80  and the third fastener  82  and is made of polymer material such as PTFE; the primary objective of disposing the ring-shaped pad  84  is to isolate and thus prevent the transparent substrate  80  from contacting the third fastener  82  so that proper flexibility is allowed to protect the transparent substrate  80  from being damaged. Furthermore, after the third fastener  82  is disposed on the lower cover of inner container  20 , the third fastener  82  and the outer surface of lower cover of inner container  203  are at the same horizontal level, and thus the placement of the inner container  2  in the outer container  2  will not be hindered. The third fastener  82  of the present invention is lock-fastened onto the outer surface of lower cover of inner container  203  of lower cover of inner container  20  via a screw, and the way of lock-fastening is not limited in the present invention. 
     Referring to  FIG. 7 , which is a sectional view of the reticle pod of the present invention. As shown in  FIG. 7 , the reticle  9  is first placed on the lower cover of inner container  20  of the inner container  2 , and, as described above, the four corners of the lower surface  91  of the reticle  9  will be first placed on the supporting protruding points  705  of the limiters  70  disposed on the four corners of the first inner surface of inner container  201 . The two columns  703  on two sides of each supporting protruding point  705  will be located right on the periphery  95  of the reticle  9  (namely, two sides of the right-angle corner). Thus, the two sides of each of the four right-angle corners of the reticle  9  will be respectively clamped by each convex column  703  and the reticle  9  can be prevented from shifting. In the following, facilitated by the guidance of the foolproof structure  60  of the upper cover of inner container  22 , the upper cover of inner container  22  is joined with the lower cover of inner container  20  in the designated direction and an inner container  2  for protecting the reticle  9  is thus formed. 
     Then, the inner container  2  is placed onto the plurality of first supporters  30  of the lower cover of outer container  10  of the outer container  1 ; wherein, the first supporters  30  correspond to the positioning groove  207  of the outer surface of lower cover of inner container  203  of the lower cover of inner container  20  (referring to  FIG. 6 ), and therefore, the inner container  2  is guided by the positioning groove  207  to the correct position when being placed. The upper cover of outer container  12  is then closed; wherein, when the upper cover of outer container  12  is to be closed, each of the second supporters  32  on the upper cover of outer container  12  aligns with the retainer  40  in each of the through holes  225  of the upper cover of inner container  22 . When the upper cover of outer container  12  is closed, each second supporter  32  is driven by the closing action to exert a downward force and impose pressure on the exposed portion of the retainer  40  in the through hole  225 ; when the retainer  40  is pressed, the O-shaped protruding portion  403  will then impose pressure on the O-shaped spring element  42  in the O-shaped recess  2251 , and the retainer  40  will then press further down and inward (i.e. when the O-shaped spring element  42  is pressed, there is flexible space for the retainer  40  to press inward, and contrariwise, when the O-shaped spring element  42  is not pressed, its flexibility facilitates the retainer  40  to resume the original position); the supporting convex pillars  401  integrated with the O-shaped protruding portions  403  will also be pressed down and inward and will then be in contact with four corners of the upper surface  93  of the reticle  9 , in other words, when the upper cover of outer container  12  is closed, the supporting convex pillars  401  of the retainers  40  at four corners of the reticle  9  will press the four corners of the upper surface  93  of the reticle  9 , and therefore the reticle  9  can be stably fastened in the inner container  2  with the existent support from the supporting protruding points  705  of the four corners of the lower surface  91  of the reticle  9 ; the inner container  2  can also be stabilized with the second supporters  32  of the upper cover of outer container  12  pressing inward, and the security of the reticle  9  in the storing and transporting process is further ensured. 
     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.