Abstract:
A dust filter mounted in a semiconductor waste gas treatment equipment comprising a housing having a chamber in the housing for passing a gas containing a water molecular and a dust through; and one or more main filtration boxes which can be implanted into the chamber by withdrawing way. One or more capturing rings and a filtering cotton for filtering the water molecular and the dust from the gas being disposed in the main filtration box, and the gas being sequentially passed through the capturing ring and the filtering cotton. It is an objective to solve a problem saying that it is not easy to clean the conventional dust filter because the structure of it is too complex.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a structural technique of a dust filter, especially to a dust filter mounted in a semiconductor waste gas treatment equipment. 
         [0003]    2. Description of Related Art 
         [0004]    In conventional semiconductor processes, many harmful waste gases, such as, a monosilane, a chlorine gas, perfluorinated compounds, etc, will be produced. In order to prevent the waste gases from damaging external environment and public benefits, the damaging substances in the waste gases should be cleaned and removed so as to be emitted into the external atmosphere. 
         [0005]    For conventional methods for treating a waste gas in a semiconductor process, the waste gases are injected into a waste gas treatment equipment, burned in high temperature flame and mixed with a high temperature gas to form a high temperature waste gas and to force the damaging substances in the high temperature waste gas into catalytic transition of high temperature, and decomposed into non-harmful substances. Thus, the water soluble harmful substances, such as, Chlorofluorocarbon, etc, in the waste gas are dissolved in water by using a sprinkling device in the waste gas treatment equipment, and the waste gas is transformed into non-harmful gas. After the gas is cooled to be emitted into the external atmosphere, the environment is polluted. Generally, before the gas is emitted into the external atmosphere, it is necessary to screen the gas by using a dust filter so as to eliminate and remove water molecular and dust in the gas. 
         [0006]    For the current treatment techniques, the dust filter is generally a so-called cyclone filtering device. The gas is passed through the cyclone filtering device to use centrifugal force and inertia produced by a whirl rotation in the dust filter. The water molecular and dusts in the gas are separated from the gas by using a principle saying that both a specific density of the water molecular and a specific density of the dust are higher than that of gas so as to remove the water molecular and the dusts from the gas. 
         [0007]    Because we want to obtain better effects of filtering the water molecular and the dusts from the gas by using the cyclone filtering device, an air blower is needed and a vortex air guide channel having a complex structure is needed to be constructed. Thus, gas is driven and forced to flow through the vortex air guide channel by means of the air blower to filter the water molecular and the dusts from the gas. However, it is not easy to clean the cyclone filtering device because the structure of the cyclone filtering device is too complex. 
       SUMMARY OF THE INVENTION 
       [0008]    It is an objective of the present invention to solve a problem saying that it is not easy to clean the conventional dust filter because the structure of it is too complex. 
         [0009]    In order to solve the problem, it is another objective of the present invention to provide a dust filter mounted in a semiconductor waste gas treatment equipment comprising: 
         [0010]    a housing having a chamber in the housing for passing a gas containing a water molecular and a dust through; and 
         [0011]    one or more main filtration boxes which can be implanted into the chamber by withdrawing way, one or more capturing rings and filtering cotton for filtering the water molecular and the dust from the gas being disposed in the main filtration box, and the gas being sequentially passed through the capturing ring and the filtering cotton. 
         [0012]    According to the present invention, a shape of the capturing ring is preferably spiral ring shape and the capturing ring preferably has an axis line. 
         [0013]    According to the present invention, the capturing ring preferably has a plurality of tongue strips formed on a circumferential wall of the capturing ring extending at a direction of the axis line. 
         [0014]    According to the present invention, the tongue strip is preferably of wavy shape. 
         [0015]    According to the present invention, the one or more capturing rings are preferably arranged in an array way alternatively and axis lines of the one or more capturing rings are preferably mutually parallel. 
         [0016]    According to the present invention, the one or more capturing rings are preferably arranged in a two layer structure and the axis lines of the one or more capturing rings are preferably not staggered. 
         [0017]    According to the present invention, the main filtration box preferably comprises a first filtration box and a second filtration box and the first filtration box and the second filtration box are spaced apart from each other in the chamber. 
         [0018]    In accordance to the above technical plan, the technical effects of the present invention are that the harmful substances dissolvable in water are removed in the waste gas treatment equipment of the present invention to produce a non-harmful gas. The gas in the waste gas treatment equipment can be guided and moved through a structure of the dust filter by natural draining pressure of the gas without usage of an air blower for driving and pushing the gas to move forward. The structure of the dust filter is effectively simplified. The main filtration boxes can be designed to be implanted into the chamber by withdrawing way for facilitating withdrawal of the main filtration box. For cleaning and dust clearing operation by the capturing rings and filtering cotton, the cleaned main filtration box is pushed into the housing to increase convenience of dust filter cleaning. 
         [0019]    Other objectives, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a three-dimensional explosive diagram of a dust filter mounted in a semiconductor waste gas treatment equipment of the present invention. 
           [0021]      FIG. 2  a cross-section view showing combined structure of  FIG. 1  of the present invention. 
           [0022]      FIG. 3  is a three-dimensional schematic diagram showing a capturing ring according to the invention. 
           [0023]      FIG. 4  a three-dimensional schematic diagram showing stacked structure of  FIG. 3  of the capturing ring of the present invention. 
           [0024]      FIG. 5  a cross-section view showing the application of the dust filter mounted in the semiconductor waste gas treatment equipment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    The scope and contents of the present invention are not limited to a scope of the following examples. 
         [0026]    Please refer to  FIGS. 1 and 2  which demonstrate a preferred embodiment of the present invention. The dust filter mounted in a semiconductor waste gas treatment equipment of the present invention comprises a housing  10  and at least one main filtration box  20 . 
         [0027]    The housing  10  can be made by screwing or welding a metal plate (such as a stainless steel plate). A chamber  11  is formed in the housing  10 . An incoming gas end  12  and an outgas end  13  for connecting to the chamber  11  are respectively formed on a surface of the housing  10  so that a gas can enter the chamber  11  through the incoming gas end  12  and exits from the outgas end  13 . The term “gas” used in the present invention means that a non-harmful gas is produced after a waste gas generated in a semiconductor process is heated and water cleaned. 
         [0028]    The main filtration box  20  is inserted into the chamber  11  of the housing  10 . An opening  15  is formed at one side of the housing  10 . The main filtration box  20  is inserted into the chamber  11  via the opening  15 . In an example, a sliding rail  16  extending toward the chamber  11  is disposed at the opening  15  of the housing  10 . A pair of guide slots  25  corresponding to the sliding rail  16  are respectively formed at both sides of the main filtration box  20 . After the main filtration box  20  is guided by the sliding rail  16  and the guide slots  25 , the main filtration box  20  is inserted into the chamber  11  via the opening  15 . In other words, by means of the above design, the main filtration box  20  is removable and is inserted into the chamber  11  or is withdrawn from the chamber  11 . 
         [0029]    A cover  24  is disposed at one side of the main filtration box  20 . An area of the cover  24  is larger than that of the opening  15 . When the main filtration box  20  is inserted into the chamber  11 , the opening  15  is covered by the cover  24  in order to preventing the gas from leaking to the outside through a gap located between the opening  15  and the main filtration box  20 . A handle (not shown) is disposed on the cover  24  during implementation. By the handle the main filtration box  20  is inserted into the chamber  11  or is withdrawn from the chamber  11 . 
         [0030]    A plurality of capturing rings  30  and a filtering cotton  40  are disposed in the main filtration box  20  in an example. For the capturing rings  30  and the filtering cotton  40  two passages of filter material for filtering water molecular and dusts in the gas are formed in the main filtration box  20 . When the gas moves through the main filtration box  20 , the water molecular and dusts in the gas are removed by passing through the capturing rings and the filtering cotton  40 . 
         [0031]    Please refer to  FIGS. 2 and 3  which demonstrate the capturing ring  30  can be made by bending a metal plate. An axis line  31  is shown on the capturing ring  30 . A fluid passage for passing the gas is formed in the capturing ring  30  extending along the axis line  31 . In one example, a plurality of tongue strips  33  extending in a direction toward the axis are formed on an annual wall  32  of the capturing ring  30 . The tongue strip  33  has a function of increasing a contact surface of the capturing ring  30  contacting with the gas. In one example, a shape of the tongue strip  33  is wavy. In more details, the tongue strip  33  in the example is made by punching the annual wall  32  of the capturing ring  30 . For the tongue strip  33  the adherence of water molecular on a metal surface is used to capture the water molecular and dusts in the gas. 
         [0032]    Please refer to  FIGS. 1 and 2  which demonstrate a staggered array arrangement of the capturing rings  30  disposed in the main filtration box  20  so that the axis lines  31  of the capturing rings  30  are mutually parallel. The fluid passages in the capturing rings  30  are aligned at the same direction in order to facilitating moving of the gas through the capturing rings  30 . In other word, please refer to  FIG. 4  which demonstrates that the capturing rings  30  are arranged in two layer structure. The directions of the axis lines  31  of the capturing rings  30  are not intersected so that the appearance of the capturing rings  30  are staggered in order to increase a contact area between the tongue strips  33  in the capturing rings  30  and the gas and to increase effect of capturing a water molecular and a dust from the gas by the capturing rings  30 . 
         [0033]    The main filtration box  20  in an example comprises a first filtration box  21  and a second filtration box  22 . The first filtration box  21  and the second filtration box are spaced apart from each other and disposed in the chamber  11 . The effect of filtering the water molecular and the dusts from the gas by disposing the first filtration box  21  and the second filtration box  22  in the chamber  11  is increased. In one embodiment, a spacer plate  23  is disposed between first filtration box  21  and the second filtration box  22  in the chamber  11 . The spacer plate  23  is used for increasing duration and lengthening a moving route of the gas passing through the chamber  11 . The filtering cotton is disposed on spacer plate  23  to increase the effect of filtering the water molecular and the dusts from the gas. 
         [0034]    After the water molecular and the dusts are filtered from the gas by the capturing rings  30  and the filtering cotton  40 , the water molecular accumulated on the capturing rings  30  and the filtering cotton  40  will condense into water which drops to a bottom of the chamber  11 . In order to avoid overflowing of the water to other location (such as, waste gas treatment equipment) because of too much amount of water accumulated, it is necessary to disposing a draining outlet  14  for draining water at a bottom of the housing  10 . A nozzle  17  of a clean dry air and a pressure detecting meter  18  are disposed near the outgas end  13  of the housing  10 . The nozzle  17  of the clean dry air can release dry dean gas which is mixed with the gas flowing to the outgas end  13 . The pressure detecting meter  18  is used for detecting a pressure value of the gas moving through the outgas end  13 . 
         [0035]    Please refer to  FIG. 5  which demonstrates that the housing  10  is connected to a degassing hole  52  of a semiconductor waste gas treatment equipment  50 . A heating decomposition zone  53 , a first water washing area  54  and a second water-washing area  55  are sequentially disposed in the semiconductor waste gas treatment equipment  50 . The waste gas  61  is injected into the semiconductor waste gas treatment equipment  50  via a gas inlet  51 . When the waste gas  61  moves through the heating decomposition zone  53 , the harmful substances in the waste gas  61  are catalyzed by using a high heat of a flame or a hot air to be decomposed into non-harmful substances. The waste gas  61  sequentially moves through the first water washing area  54  and the second water-washing area  55 . Thus, water  62  is spraying in a homogeneous water curtain shape so as to generate a sufficient contact between the water  62  and the waste gas  61 . The harmful substances in the gas soluble in the water  61  are dissolved in the water  62  to transform the waste gas  61  into non-harmful gas  63  and the non-harmful gas  63  enters the housing  10  via the degassing hole  52 . The amount of the water molecular and the dusts containing in the non-harmful gas  63  decrease by moving through the main filtration box  20  in the housing  10  in order to be drained to the external atmosphere. 
         [0036]    Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that any other possible modifications and variations can be made without departing from the scope of the invention as hereinafter claimed.