Abstract:
A reticle pod for storing reticles, into the gas channel of partition of which gas is filled through a gas inlet, wherein strong gas flow is formed around the pellicle film and the pellicle film expands outward in accordance with the Bernoulli&#39;s principle; when no gas is filled in through the gas inlet, the pellicle film contracts inward. Therefore, by turning on and shutting off the gas inlet valve, the pellicle film will be set in a breathing motion for the gas inside the pellicle film to be exchanged.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a storage device for storing semiconductor components or reticles, and more particularly, to a reticle pod having the function of gas exchange in the pellicle film. 
     2. Description of the Prior Art 
     In the rapidly developing modern semiconductor technology, optical lithography tool plays an important role. 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 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, specific circuit pattern can be exposed on the silicon wafer. However, since any kind of dust (such as particles, powders, and organic matters) adhering to the reticle can cause degradation of the quality of the projected pattern, the reticle used to produce pattern on silicon wafers is required to be kept absolutely clean, and the silicon wafers or other semiconductor components on which pattern is to be produced also have to be kept absolutely clean. Therefore in ordinary wafer processes, clean rooms are provided for preventing from contamination caused by particles in the air. However, the status of absolute dustless is still inaccessible in clean rooms at present. 
     Thus, in modern semiconductor processes, contamination-resistant reticle pods are employed for storing and transporting reticles to maintain the cleanliness of reticles; and contamination-resistant semiconductor storage device are also employed for storing and transporting semiconductor components to maintain the cleanliness of semiconductor components. The reticle pods are used to store reticles in semiconductor process to facilitate carrying and transporting of reticles between platforms and to isolate the reticles from air for preventing from contamination of reticles caused by impurities and thus leading to changes; the semiconductor storage devices are used to store semiconductor components in semiconductor process to facilitate carrying and transporting of semiconductor components between platforms and to isolate the semiconductor components from air for preventing from contamination of semiconductor components caused by impurities and thus leading to changes. Therefore, in advanced semiconductor Fabs, the cleanliness of reticle pods and semiconductor storage devices is required to comply with SMIF, i.e. the cleanliness is maintained below Class 1. 
     A reticle pod of conventional art, as shown in  FIG. 7 , usually comprises a shell a, on which are disposed with multiple supporting components c for sustaining reticle d. The supporting components c can sustain the lower surface of reticle d and restrict the two edges of the reticle, and the supporting components c can be rested on by the reticle for securing the reticle. A base b opposite to the shell a, which covers and joins with the shell a to form a space for storing reticle d. Meantime, gas is filled into the storage device of reticle d to maintain the cleanliness. 
     However, in order to further increase the yield of products and reduce the cost of production, not only is the standard of cleanliness to be complied to, but the problem of pollution of reticles caused by external gas is also to be overcome. The sources of external gas include, in addition to air, outgas released by the storage device itself which is made of polymer material and volatile gas generated from residue of trace amount of chemical solution on reticles or semiconductor components. These unexpected gases will cause haze on the surface of reticles or semiconductor components, which will then make reticles or semiconductor components defective and discardable and lead to increase of production cost. It is thus an important issue to explore how to solve the problem of reticle haze by filling in gas in reticle pods of prior art. Taking the aforementioned concern into consideration, the present invention provides a reticle pod having the function of gas exchange in pellicle film. 
     SUMMARY OF THE INVENTION 
     According to the description above, one primary object of the present invention is to provide a gas exchange device disposed in the reticle pod, the structure of which is designed to generate strong gas flow and set the pellicle film in floating motion in accordance with the Bernoulli&#39;s principle and is thus able to achieve the function of gas exchange in the pellicle film. 
     Another primary object of the present invention is to provide a gas exchange device disposed in the reticle pod, in which the function of gas exchange in the pellicle film on the reticle is achieved by controlling the switching-on and shutting-off of the gas filling into the reticle pod. Therefore, impurities and volatile chemical gases in the interior can be brought out and the cleanliness of storage device can be enhanced, and thus the product yield is increased and the cost of defective reticles is reduced. 
     According to the objects above, the present invention first provides a reticle pod disposed with gas exchange structure. The reticle pod is composed with a cover with a first circumferential wall and a base with a second circumferential wall on which at least a pair of upwardly protruding through holes are disposed, an accommodation space being formed by the first circumferential wall and the second circumferential wall for accommodate and fasten a reticle substrate. The characteristic of the reticle pod is that a gas exchange structure is installed on the second circumferential wall of the base, wherein the gas exchange structure comprises: a gas chamber base, four edges of which extend upward to form a third circumferential wall; at least a pair of downwardly protruding through holes disposed on said gas chamber base and opposite to each other at a distance, the position of the at least a pair of downwardly protruding through holes corresponding to that of the at least a pair of upwardly protruding through holes on the base; a first partition disposed on the third circumferential wall of the gas chamber base, a gas chamber being formed between the first partition and the gas chamber base and a gas channel being formed on the first partition; a second partition disposed on the first partition, a gas flow guiding room being formed between the second partition and the first partition and a gap being formed between the third circumferential wall and the second partition whose square measure is smaller than that of the first partition. 
     The present invention then provides a reticle pod disposed with gas exchange structure. The reticle pod is composed of a cover with a first circumferential wall and a base with a second circumferential wall; an accommodation space is formed by the first circumferential wall and the second circumferential when the cover closes and joins with the base for accommodating and fastening a reticle substrate. At least a pair of upwardly protruding through holes are disposed on the second circumferential wall. The characteristic of the reticle pod is that a gas exchange structure is installed on the second circumferential wall of the base, wherein the gas exchange structure comprises: a gas chamber base, the four edges of which extending upward to form a third circumferential wall; at least a pair of downwardly protruding through holes disposed on the gas chamber base and opposite to each other at a distance, the location of the at least a pair of downwardly protruding through holes corresponding to that of the at least a pair of upwardly protruding through holes; a first partition disposed on the third circumferential wall of the gas chamber base, a gas chamber being formed between the first partition and the gas chamber base and a gas channel being formed on the first partition; a second partition disposed on the first partition, a gas flow guiding room being formed between the second partition and the first partition and a gap being formed between the third circumferential wall and the second partition whose square measure is smaller than that of the first partition; and a reticle substrate, the structure of which comprises: an upper surface and a lower surface, a rectangular frame with certain thickness formed on the upper surface of the reticle substrate; a ventilation hole disposed on one edge of the rectangular frame, a pellicle film layer formed on said rectangular frame such that a close space to be formed by said pellicle film layer supported with the thickness of said rectangular frame and the upper surface of said reticle substrate. 
     The present invention then provides a reticle pod disposed with gas exchange structure, which is composed by a cover with a first circumferential wall and a base with a second circumferential wall on which are at least a pair of upwardly protruding through holes, an accommodation space being formed by the first circumferential wall and the second circumferential wall for accommodating and fastening a reticle substrate, the characteristic of the reticle pod being that a gas exchange structure is installed on the second circumferential wall of the base, wherein the gas exchange structure comprises: a gas chamber base, four edges of which extend upward to form a third circumferential wall; at least a pair of downwardly protruding through holes disposed on the gas chamber base and opposite to each other at a distance, the position of the at least a pair of downwardly protruding through holes corresponding to that of the at least a pair of upwardly protruding through holes; a first partition disposed on the third circumferential wall of the gas chamber base, a gas chamber being formed between the first partition and the gas chamber base and a gas channel being formed on the first partition; a second partition disposed on the third circumferential wall, a gas flow guiding room being formed between the second partition and the first partition, and a plurality of gaps are disposed on four sides of the second partition. 
     With the design provided by the present invention, gas in the pellicle film can be speedily exchanged anytime and anywhere, and damages to important patterns in the reticle caused by impurities deposited in the interior or volatile chemical gases generated from operation process can be further prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of the present invention; 
         FIG. 2  is a top view of the base of the first embodiment of the present invention; 
         FIG. 3  is a top view of the first partition of the first embodiment of the present invention; 
         FIG. 4  is a top view of the second partition of the first embodiment of the present invention; 
         FIG. 5A  is a top view of the second partition of another embodiment of the present invention; 
         FIG. 5B  is a sectional view of the second partition of another embodiment of the present invention; 
         FIG. 6A  is a sectional view of the first embodiment of the present invention in gas-filling status; 
         FIG. 6B  is a view of the first embodiment of the present invention in the status in which gas filling is terminated; 
         FIG. 7  is a view of the reticle pod of prior art. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention discloses a reticle pod disposed with gas exchange structure. Some structures and employments of reticles, reticle pods, or supporting components or gas inlets in reticle pods are achieved by employment current technology and are thus not detailedly described in the following description. Moreover, the drawings referred to in the following are not made according to actual sizes or in a complete manner, the function of which is only to illustrate characteristics of the present invention. 
     First, referring to  FIG. 1 , which is a sectional view of reticle pod of the present invention having gas exchange function. As shown in  FIG. 1 , the reticle pod is composed of an upper cover  10 A and a lower cover  10 B, wherein the upper cover  10 A is formed by a cover  10 AA and a first circumferential wall  103  connected to the cover  10 AA, and the lower cover  10 B is formed by a base  10 BB and a second circumferential wall  105  connected to the base  10 BB. An accommodation space is formed by the first circumferential wall  103  of the cover  10 A and the second circumferential wall  105  of the cover  10 B for accommodating a reticle. Wherein the second circumferential wall  105  is disposed with at least a pair of upwardly protruding through holes  13 , on which a gas exchange structure is installed for forming dynamic gas flow field in the interior of reticle pod with gas that is filled in. 
     The gas exchange structure of the present invention comprises a gas chamber base  100  and a third circumferential wall  107  connecting with four edges of the gas chamber base  100  and extending upward; the gas chamber base  100  is disposed with at least a pair of downwardly protruding through holes  15 , the position of which corresponds to that of the pair of upwardly protruding through holes  13  on the second circumferential wall  105 . In the present embodiment, the downwardly protruding through holes  15  are larger than the upwardly protruding through holes  13  on the second circumferential wall  105 . Therefore, the gas exchange structure can be assembled via the through holes  15  and the through holes  13  on the second circumferential wall  105 ; for example, when the gas exchange structure is installed on the second circumferential wall  105 , the upwardly protruding through holes  13  snap fit with the downwardly protruding through holes  15  and the protruding parts of the downwardly protruding through holes  15  contact the second circumferential wall  105  after being snap-fitted; therefore, a distance is kept between the gas exchange structure and the second circumferential wall  105 . When the upwardly and downwardly protruding through holes  13  and  15  are joined with each other, the upwardly protruding through holes  13  and the downwardly protruding through holes  15  are connected and form a pair of gas channels, the at least a pair of gas channels comprising at least a gas inlet  101  and at least a gas outlet  102 . Then, a first partition  20  is disposed at interval on the third circumferential wall  107  for a gas chamber  11  to be formed between the gas chamber base  100  and the first partition  20 , wherein a gas channel  201  is formed on the first partition  20  near the center. And then, a second partition  30  is disposed at interval and fastened onto the first partition  20  for a gas flow guiding room  21  to be formed, as shown in  FIG. 1 . 
     A reticle substrate  40 , comprising an upper surface  41  and a lower surface  42 , a rectangular frame  43  with certain thickness formed on the upper surface  41  of the reticle substrate  40 , the size of the frame  43  being the same as that of the gas exchange structure, a ventilation hole  49  disposed on one edge of the rectangular frame  43 , and a pellicle film layer  45  further formed on the rectangular frame  43  such that a close space  47  to be formed by the pellicle film layer  45  supported with the thickness of the rectangular frame  43  and the upper surface  41  of the reticle substrate  40 . Similar to the prior art, the reticle substrate  40  is fastened right on top of the third partition  30  when it is placed between the upper cover  10 A and the lower cover  10 B of the reticle pod for a distance to be kept between the pellicle film layer  45  disposed on the frame  43  and the third partition  30 . 
     Then, referring to  FIG. 2 ,  FIG. 3 , and  FIG. 4 , which are top views of each partition in the gas exchange structure of the present invention. First, as shown in  FIG. 2 , a gas chamber base  100  is disposed with at least a pair of downwardly protruding through holes  15 ; in a preferred embodiment, the gas chamber base  100  is disposed with two pairs of downwardly protruding through holes  15  and the base  10 BB is also disposed with two pairs of upwardly protruding through holes  13 ; the downwardly protruding through holes  15  and the upwardly protruding though holes  13  join together and form a pair of gas inlets  101  and a pair of gas outlets  102 . When the reticle pod is placed on a load port (not shown in Figure), the gas purging device and the gas exhausting device (not shown in Figure) contact the gas inlets  101  and the gas outlets  102 , and dry, clean gas is filled into the air-tight reticle pod by the gas purging device and gas in the reticle pod is then exhausted by the gas exhausting device; a gas flow field is thus formed in the reticle pod. Then, referring to  FIG. 3 , a gas channel  201  is disposed on a first partition  20  near the center, the function of which is to provide flowing route for the filled-in gas to follow when gas is filled into the gas chamber  11  between the gas chamber base  100  and the first partition  20 . Apparently, when the filled-in gas flows out along the gas channel  201 , the velocity of filled-in gas increases. The smaller the gas channel  201  is, the higher the velocity of filled-in gas becomes. Moreover, the shape of gas channel  201  is not limited in the present embodiment and can also be formed by, for example, a plurality of through holes. Furthermore, referring to  FIG. 4 , a second partition  30  is fastened onto the first partition  20  for a gas flow guiding room  20  to be formed between the second partition  30  and the first partition  20 . The method for fastening can be, for example, using pillars at four corners of the second partition  30  for fastening the second partition  30  onto the first partition  20  and is not limited in the present invention. Meantime, a gap is evenly kept between the second partition  30  and the third circumferential wall  107  of the gas chamber base  100 ; when the filled-in gas flows out of the gas channel  201  at high velocity, the second partition  30  blocks the high-velocity gas flow and forces the gas to flow out of the gap between the second partition  30  and the third circumferential wall  107 . Therefore, it is apparent that the square measure of the second partition  30  of the present invention is smaller than that of the first partition  20 . 
     In addition, another embodiment of the second partition  30  is shown in  FIG. 5A  and  FIG. 5B . First, referring to  FIG. 5A , the second partition  30  is disposed and fastened onto the first partition  20  for a gas flow guiding room  21  to be formed between the second partition  30  and the first partition  20 . The second partition  30  is fastened between the third circumferential wall  107  of the base  10 B and the first partition  20 , and therefore a gas flow guiding room  21  can be formed between the second partition  30  and the first partition  20 . As the second partition  30  is fastened to the third circumferential wall  107 , the gap  301  disposed around the second partition  30  can force the high-velocity gas flow to flow out from the gap  301  of the third partition  30 . Meantime, the shape of gap  301  is not limited in the present embodiment. 
     What is to be emphasized in the following is that, the gas exchange structure in the present embodiment can be manufactured by integrated molding, for example, by applying injection molding or injection-press molding technologies, and the material can be polymer material. Moreover, the gas exchange structure in the present embodiment can also be formed by assembly, for example, by assembling parts manufactured by stamping process such as gas chamber base  100 , first partition  20 , and second partition  30 , and the material can be polymer material or metal material. 
     And then, referring to  FIG. 6A , which is a view of reticle pod having gas exchange structure of the first embodiment of the present invention in the gas-filling status. After the reticle pod is carried onto the load port, at the time for filling in gas, the gas purging device is controlled by the load port to fill gas into the gas chamber  11  between the gas chamber base  100  and the first partition  20  via the gas inlet  101 . When the pressure of gas filled into the gas chamber  11  reaches saturation, the gas will be brought through the gas channel  201  of the first partition  20  into the gas flow guiding room  21  between the first partition  20  and the second partition  30 . Apparently, when gas is filled from one or multiple gas inlets  101  into the gas chamber  11 , the gas flow in the gas chamber  11  will become chaotic. Therefore in the present invention, the objective of forming a gas channel  201  on the first partition  20  is to let all gas filled in from the gas inlet flow through the gas channel  201  to the gas flow guiding room  21  when the pressure of gas filled into the gas chamber  11  reaches saturation. Then, the gas in the gas flow guiding room  21  will, under the influence of the narrow space between the first partition  20  and the second partition  30  and the pushing force exerted by the gas channel  201 , flow more rapidly toward the gap between the second partition  30  and the third circumferential wall  107  of the gas chamber wall  100 . Furthermore, the gas exhausting device is at the same time controlled by the load port to exhaust gas from the gas outlet  102 . In the process of filling in gas and exhausting filled-in gas of the reticle pod performed by the gas purging device and the gas exhausting device controlled by the load port, the filled-in gas thus forms a gas flow field in the reticle pod. Then, referring to the arrows indicating directions in  FIG. 6A : when the gas flow field moves through the gas exchange structure of the gas chamber base  100 , the gas flow flows rapidly through the gap between the third circumferential wall  107  of the gas chamber base  100 . As a distance is kept between the pellicle film layer  45  on the frame  43  of reticle substrate  40  and the third circumferential wall  107 , the gas flow field carries the gas between the pellicle film layer  45  and the second partition  30  away when the gas flow flows rapidly through the gap between the third circumferential wall  107  of the gas chamber base  100 , and thus the pressure at B is smaller than the pressure in the closed space  47  between the pellicle film layer  45  and the upper surface  41  of the reticle substrate  40 . Meantime, some gas diffuses into the closed space  47  through the ventilation hole  49  on the frame  43  and causes a downwardly pulling force to be exerted on the pellicle film layer  45  and making it incline closer to the second partition  30 , which is a physical phenomenon in accordance with the Bernoulli&#39;s principle. Apparently, when the frame  43  of the present embodiment is disposed with at least one or multiple ventilation holes  49 , the physical phenomenon in accordance with the Bernoulli&#39;s principle can also be formed. Such design is not limited in the present embodiment. 
     In the process of filling in gas, the gas not only diffuses into the closed space  47  through the ventilation hole  49  but also penetrates through the pellicle film layer  45 . In the early stage of employment of pellicle film layer  45 , the penetration rate of the pellicle film layer  45  is higher and thus the gas exchange efficiency can be increased by increasing the gas flow rate; however, at the final stage of employment, gas-exchange resistance in the gas exchange process increases as the penetration rate of the pellicle film layer  45  becomes low and the deformation rate of pellicle film also increases. In order to keep the deformation of the pellicle film layer  45  within affordable degree at the final stage of employment of pellicle film layer  45 , the rate of gas flow filled in has to be properly adjusted as lower to extend the duration of pellicle film. 
     Then, referring to  FIG. 6B , which is a view of reticle pod having gas exchange structure of the present invention in the status in which gas-filling is terminated. When the gas purging device is controlled by the load port to stop filling in gas through the gas inlet  101 , the field formed by gas flow thus disappears. Meantime, in accordance with Bernoulli&#39;s principle, the pressure at A and the pressure at B in the interior of reticle pod resumes to be balanced, and the downwardly pulling force exerted on the pellicle film layer  45  disappears. Thus, the pellicle film layer  45  resumes to original status, and with the force generated by the pellicle film layer  45  when resuming to original status, gas in the closed space  47  can be exhausted from the ventilation hole  49 . Then, the gases are exhausted from the gas outlet  102  by the gas exhausting device and out of the reticle pod. Apparently, in the reticle pod of the present embodiment, in the process in which gas is filled in by the gas purging device controlled by the load port or the gas-filling is terminated, the phenomenon of gas flow field in accordance with Bernoulli&#39;s principle sets the pellicle film layer  45  in motion, the motion of which is similar to the breathing motion of human beings. And thus by controlling the regular motion generated between the pellicle film layer  45  on the reticle substrate  40  and the frame  43 , impurities in the closed space  47  or on the upper surface  41  on reticle substrate  40  or volatile chemical gases can be carried out to achieve the function of cleaning. 
     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.