Patent Publication Number: US-2012024478-A1

Title: Showerhead

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to semiconductor equipment, and more particularly to a showerhead. 
     2. Description of Related Art 
     Semiconductor manufacturing equipment is commonly used in the production of semiconductor components. The semiconductor manufacturing equipment typically has a reaction chamber. The reaction gases which are required by the semiconductor manufacturing process can be provided into the reaction chamber by the showerhead of the reaction chamber.  FIG. 1  shows a sectional view of a conventional showerhead  100 . The conventional showerhead  100  includes a bottom portion  110 , a plurality of gas tubes  120 , a first plate  131 , a second plate  132 , and a top portion  140 . The gas tubes  120  include a plurality of first gas tubes  121  and a plurality of second gas tubes  122 . Moreover, the conventional showerhead  100  includes a first space  191 , a second space  192 , and a third space  193 . A first process gas and a second process gas can flow into the second space  192  and the third space  193  respectively. The first process gas and the second process gas can also flow into the inside of the reaction chamber through the first gas tubes  121  and the second gas tubes  122  respectively. On the other hand, the fluid which flows into the first space  191  will not flow into the inside of the reaction chamber. Therefore, cooling fluid, such as water, can flow into the first space  191  for cooling the conventional showerhead  100 . 
       FIGS. 2A-2F  show the making steps of the conventional showerhead  100  shown in  FIG. 1 . Referring to  FIGS. 2A-2C , a bottom portion  110  and a plurality of gas tubes  120  are provided, wherein the bottom portion  110  has a plurality of openings. Then, the gas tubes  120  are inserted into the openings of the bottom portion  110 . After that, a soldering process, such as a high temperature soldering process (hard soldering or brazing), is performed for fixing the gas tubes  120  on the openings of the bottom portion  110  and sealing the clearances between the gas tubes  120  and the openings. In the real case, the number of the gas tubes  120  can be thousands. Therefore, the step of inserting the gas tubes  120  into the openings of the bottom portion  110  may cost a long period of time. The quality of the conventional showerhead  100  is affected by the sealing performance of sealing the clearances between the gas tubes  120  and the openings of the bottom portion  110 . 
     Referring to  FIGS. 2D-2F , a first plate  131  and a second plate  132  are provided, wherein the first plate  131  and the second plate  132  have a plurality of openings respectively. Then, the gas tubes  120  are inserted into the openings of the first plate  131  and the second plate  132 . After that, a soldering process, such as a high temperature soldering process (hard soldering or brazing), is performed for fixing the gas tubes  120  on the openings of the first plate  131  and the second plate  132 . The high temperature soldering process is also performed for sealing the clearances between the gas tubes  120  and the openings of the first plate  131  and the second plate  132 . Finally, the top portion  140  is provided and assembled to the bottom portion  110  so as to finish the making steps of the conventional showerhead  100 . 
     The quality of the high temperature soldering process is very important for the conventional showerhead  100 . Any one of the gas tubes  120  which is not soldered properly may cause the whole conventional showerhead  100  to fail. For example, a first process gas and a second process gas can flow into the second space  192  and the third space  193  respectively. If leakage happened between the second space  192  and the third space  193 , the first process gas and the second process gas are mixed within the conventional showerhead  100 . The particles which are formed by the first process gas and the second process gas may clog the gas tubes  120 . 
     Moreover, high temperature, thermal cycling, and corrosion caused by reaction gases may damage the soldering portions for sealing the clearances between the gas tubes  120  and the openings of the bottom portion  110 . The cooling fluid within the first space  191  may leak into the inside of the reaction chamber. Thus, the process yields are affected by the cooling fluid. 
     For the reason that there are some disadvantages of the prior art mentioned above, there exists a need to propose a novel showerhead. Different process gases will not be mixed within the showerhead. The showerhead has better ability for bearing high temperature, thermal cycling, and corrosion caused by reaction gases. The showerhead has longer lifetime, and the cooling fluid will not leak into the inside of the reaction chamber and affect the process yields. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been made in order to meet such a need described above, and it is an object of the present invention to provide a novel showerhead. The showerhead has better ability for bearing high temperature, thermal cycling, and corrosion caused by reaction gases. The showerhead has longer lifetime, and the cooling fluid will not leak into the inside of the reaction chamber and affect the process yields. 
     In order to achieve the above object, the present invention provides a showerhead. The showerhead includes a bottom plate, a channel plate, and a top plate. The bottom plate includes a plurality of cooling channels and a plurality of gas holes, wherein the gas holes includes at least one first gas hole and at least one second gas hole. The channel plate includes a first trench area and a second trench area, wherein the first gas hole is connected with the first trench area, and the second gas hole is connected with the second trench area. The top plate is coupled to the channel plate. 
     According to the showerhead of the present invention, the gas holes are formed on the bottom plate and the channel plate. There is no need to use gas tubes. Different process gases will not be mixed within the showerhead. The leakage caused by clearances between the gas tubes and the bottom portion is also avoided. Therefore, the showerhead has better ability for bearing high temperature, thermal cycling, and corrosion caused by reaction gases. Thus, the showerhead has longer lifetime, and the cooling fluid will not leak into the inside of the reaction chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a sectional view of a conventional showerhead; 
         FIGS. 2A-2F  show the making steps of the conventional showerhead shown in  FIG. 1 ; 
         FIG. 3A  shows a sectional view of the showerhead in accordance with an embodiment of the present invention; 
         FIG. 3B  shows a top view of an example of the channel plate shown in  FIG. 3A ; 
         FIG. 3C  shows a top view of another example of the channel plate shown in  FIG. 3A ; and 
         FIGS. 4A-4D  show the making steps of the showerhead shown in  FIG. 3A . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The detailed description of the present invention will be discussed in the following embodiments, which are not intended to limit the scope of the present invention, but can be adapted for other applications. While drawings are illustrated in detail, it is appreciated that the quantity of the disclosed components may be greater or less than that disclosed, except where expressly restricting the amount of the components. 
       FIG. 3A  shows a sectional view of a showerhead  200  in accordance with an embodiment of the present invention. The showerhead  200  includes a bottom plate  210 , a channel plate  220 , and a top plate  230 . The bottom plate  210  includes a plurality of cooling channels  211  and a plurality of gas holes  240 . The cooling fluid, such as water, can flow into the cooling channels  211  for cooling the showerhead  200 . The gas holes  240  includes at least one first gas hole  241  and at least one second gas hole  242 . The channel plate  220  includes a first trench area  221  and a second trench area  222 . The first gas hole  241  is connected with the first trench area  221 , wherein a first process gas can flow into the inside of the reaction chamber through the first trench area  221  and the first gas hole  241 . The second gas hole  242  is connected with the second trench area  222 , wherein a second process gas can flow into the inside of the reaction chamber through the second trench area  222  and second gas hole  242 . The clearances between the bottom plate  210  and the channel plate  220  are sealed by a soldering process. The top plate  230  is coupled to the channel plate  220 . 
       FIG. 3B  shows a top view of an example of the channel plate  220  shown in  FIG. 3A . The channel plate  220  includes a first trench area  221  and a second trench area  222 . The first trench area  221  and the second trench area  222  are both comb-like. The first trench area  221  interlaces the second trench area  222 . Furthermore, the first gas hole  241  is connected with the first trench area  221 , and the second gas hole  242  is connected with the second trench area  222 . The first process gas and the second process gas can flow into the inside of the reaction chamber through the first gas hole  241  and the second gas hole  242  respectively. Moreover, most of the first gas holes  241  are surrounded by the second gas holes  242 . Thus, the first process gas and the second process gas can be mixed uniformly within the reaction chamber. 
       FIG. 3C  shows a top view of another example of the channel plate  220  shown in  FIG. 3A . The channel plate  220  also includes a first trench area  221  and a second trench area  222 . The first gas hole  241  is connected with the first trench area  221 , and the second gas hole  242  is connected with the second trench area  222 . The first process gas and the second process gas can also flow into the inside of the reaction chamber through the first gas hole  241  and the second gas hole  242  respectively. In this embodiment, most of the first gas holes  241  are surrounded by the second gas holes  242 . Thus, the first process gas and the second process gas can be mixed uniformly within the reaction chamber. 
     In this embodiment, the gas holes  240  are formed on the bottom plate  210  and the channel plate  220  by a mechanical process, wherein the mechanical process can include many kinds of processing methods, such as machining, electric discharge machining, or any other processing method. Any processing method which is capable of forming the gas holes  240  on the bottom plate  210  and the channel plate  220  is possible to be used. Different processing methods should be considered based on the real conditions. Although the mechanical process is used in this embodiment, the gas holes  240  can also be formed on the bottom plate  210  and the channel plate  220  by a chemical process or another processing method. 
       FIGS. 4A-4D  show the making steps of the showerhead  200  shown in  FIG. 3A . Referring to  FIG. 4A , a bottom plate  210  is provided. The bottom plate  210  includes a plurality of cooling channels  211 . Then, referring to  FIG. 4B , a channel plate  220  is provided. The channel plate  220  includes a first trench area  221  and a second trench area  222 . The channel plate  220  is coupled to the bottom plate  210 , wherein a soldering process, such as a high temperature soldering process (hard soldering or brazing), is performed for sealing the clearances between the channel plate  220  and the bottom plate  210 . 
     Referring to  FIG. 4C , a plurality of gas holes  240  are formed on the bottom plate  210  and the channel plate  220 . The gas holes  240  includes at least one first gas hole  241  and at least one second gas hole  242 , wherein the first gas hole  241  is connected with the first trench area  221 , the second gas hole  242  is connected with the second trench area  222 . 
     In this embodiment, the gas holes  240  are formed on the bottom plate  210  and the channel plate  220  by a mechanical process, wherein the mechanical process can include many kinds of processing methods, such as machining, electric discharge machining, or any other processing method. Any processing method which is capable of forming the gas holes  240  on the bottom plate  210  and the channel plate  220  is possible to be used. Different processing methods should be considered based on the real conditions. Although the mechanical process is used in this embodiment, the gas holes  240  can also be formed on the bottom plate  210  and the channel plate  220  by a chemical process or another processing method. Finally, referring to  FIG. 4D , a top plate  230  is provided and assembled to the channel plate  220  so as to finish the making steps of the showerhead  200 . 
     In this embodiment, the gas holes  240  are formed after the step of coupling the channel plate  220  to the bottom plate  210 . However, the gas holes  240  can be formed on the bottom plate  210  and the channel plate  220  respectively before the step of coupling the channel plate  220  to the bottom plate  210 . 
     According to the showerhead of the present invention, the gas holes are formed on the bottom plate and the channel plate. There is no need to use gas tubes. Different process gases will not be mixed within the showerhead. The leakage caused by clearances between the gas tubes and the bottom portion is also avoided. Therefore, the showerhead has better ability for bearing high temperature, thermal cycling, and corrosion caused by reaction gases. Thus, the showerhead has longer lifetime, and the cooling fluid will not leak into the inside of the reaction chamber. 
     Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present invention, which is intended to be limited solely by the appended claims.