Abstract:
A wafer scrubber is disclosed, including a chamber, and a holder connecting to a spindle disposed in the chamber, wherein the holder supports a wafer, and the wafer spins to remove water on the wafer, and a mashed inner cup comprising a plurality of through holes disposed between the holder and a wall of the chamber, wherein the mashed inner cup receives water from a surface of the wafer and rotates around the spindle to release the water through the through holes.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention generally relates to a wafer scrubber and more particularly to a wafer scrubber system using a high speed spinning action to remove water from a surface of a wafer. 
         [0003]    2. Description of the Related Art 
         [0004]    Production of semiconductor devices having microscopic structures require high-precision technology. During processing, minute particles of dust on the circuits which constitute a semiconductor device may degrade the reliability of a finished semiconductor device. Even if dust contaminants produced during processing, which end up on a semiconductor wafer, do not adversely affect the circuit functions of the semiconductor device, they still may lead to fabrication difficulties. Therefore, a semiconductor device must be fabricated in a dirt-free environment, and the surface of the semiconductor wafer must be washed to remove minute particles of dust generated during processing. 
         [0005]    Referring to  FIG. 1 , a conventional wafer scrubber comprises a spindle  108  connected to a holder  102  for holding a wafer  106 . The wafer  106  is moistened by deionized water  110  (DI water) in a preceding stage. The wafer  106  and the holder  102  spin with a high speed to remove water  110  from the wafer  106  surface. However, this method and scrubber make the water  110  leave the wafer  106  with a high speed, and the high speed water  110  scatters back to impact the wafer  106  when it hits the chamber wall  104 . Therefore, particle and chip damage issues are generated. 
       BRIEF SUMMARY OF INVENTION 
       [0006]    The invention provides a wafer scrubber, comprising a chamber, and holder connecting to a spindle disposed in the chamber, wherein the holder supports a wafer, and the wafer spins to release water on the wafer, and a mashed inner cup comprising a plurality of through holes disposed between the holder and a wall of the chamber, wherein the mashed inner cup receives water from a surface of the wafer and rotates around the spindle to release the water through the through holes. 
         [0007]    A wafer cleaning procedure, comprising providing a wafer scrubber comprising a chamber, and holder connecting to a spindle disposed in the chamber, wherein the holder supports a wafer and a mashed inner cup comprising a plurality of through holes disposed between the holder and a wall of the chamber, and spinning the wafer to remove water thereon, wherein the mashed inner cup receives water from a surface of the wafer and rotates around the spindle to release the water through the through holes for preventing the water from scattering back to the edge of the wafer. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]    The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein, 
           [0009]      FIG. 1  shows a conventional wafer scrubber. 
           [0010]      FIG. 2  shows a method to reduce the wafer scattering back issue. 
           [0011]      FIG. 3A  shows a cross section view of a wafer scrubber of an embodiment of the invention. 
           [0012]      FIG. 3B  shows a three dimensional view of a wafer scrubber of an embodiment of the invention. 
           [0013]      FIG. 4A  shows a cross section view of a wafer scrubber of another embodiment of the invention. 
           [0014]      FIG. 4B  shows a three dimensional view of a wafer scrubber of another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0015]    It is understood that specific embodiments are provided as examples to teach the broader inventive concept, and one of ordinary skill in the art can easily apply the teaching of the present disclosure to other methods or apparatus. The following discussion is only used to illustrate the invention, not limit the invention. 
         [0016]    Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be appreciated that the following figures are not drawn to scale; rather, these figures are merely intended for illustration. 
         [0017]      FIG. 2  shows a method to reduce the wafer  202  scattering back issue. Referring to  FIG. 2 , it is found that a hydrophilic inner surface of an inner cup can reduce the water scattering back issue. Therefore, a method changes material of the inner wall  206  to have a hydrophilic surface for preventing water  204  scattering back to hit the wafer  202  which generates particle and/or chip damage issues. However, this method cannot completely eliminate the water scattering back issue. 
         [0018]    Accordingly, a new scrubber and method are required to address the water scattering back issues. 
         [0019]      FIG. 3A  shows a cross section view of a wafer scrubber of an embodiment of the invention.  FIG. 3B  shows a three dimensional view of a wafer scrubber of an embodiment of the invention. Referring to  FIGS. 3A and 3B , a wafer holder  302  is connected to a spindle  304  in a chamber. A wafer  310  is disposed on the wafer holder  302  in a chamber  301 . The wafer  310  may be moistened by deionized water  306  (DI water) in a preceding stage. The wafer holder  302  and the wafer  310  spin with a high speed to remove water  306  from the wafer  310  surface. In an embodiment of the invention, rotation speed of the wafer  310  can be 1500 rpm˜4500 rpm. Moreover, the wafer  310  is separated from the wall  308  of the chamber  301  by a distance of about 30 mm˜150 mm. In an embodiment of the invention, the holder  302  holds the wafer  310  by an electric force or clamping. 
         [0020]    In an important aspect of the embodiment, a meshed inner cup  312  comprising a plurality of through holes  309  is provided between the wafer holder  302  and the chamber wall  308  in the chamber  301  of the wafer scrubber. In the invention, the through holes in the mashed inner cup  312  are column-shaped. In an embodiment of the invention, the meshed inner cup  312  is formed of hydrophobic material, so that the meshed inner cup  312  can catches more water  306  released from the wafer  310  surface. Alternatively, the meshed inner cup  312  is formed of hydrophilic material, so that the meshed inner cup  312  can release water  306  sooner. The meshed inner cup  312  can spin around the spindle. Rotation speed of the meshed inner cup  312  can be less than, the same as or greater than the rotation speed of the wafer  310  depending upon process conditions, such as water quantity. Further, rotation speed of the meshed inner cup  312  can vary when the quantity of the water  306  from the wafer  310  changes. The spinning mashed inner cup  312  can catch water  306  and release the water  306  via the through holes  309  in the mashed inner cup  312  to the chamber wall  308 . Therefore, the mashed inner cup  312  can catch and release water  306 , and the water  306  scattering back issue can be addressed. 
         [0021]      FIG. 4A  shows a cross section view of a wafer scrubber of another embodiment of the invention.  FIG. 4B  shows a three dimensional view of a wafer scrubber of another embodiment of the invention. Difference between the embodiment in  FIG. 3A  and  FIG. 4A  is the shape of the through holes of the mashed inner cup. Referring to  FIGS. 4A and 4B , a holder  402  is connected to a spindle in a chamber  401 . A wafer  410  is disposed on the holder  402 . The wafer  410  may be moistened by deionized water  406  (DI water) in a preceding stage. The wafer holder  402  and the wafer  410  spin with a high speed to remove water  406  from the wafer  410  surface. In an embodiment of the invention, rotation speed of the wafer  410  can be 1500 rpm˜4500 rpm. Moreover, the wafer  410  is separated from the chamber wall  408  by a distance of about 30 mm˜150 mm. In an embodiment of the invention, the holder  402  holds the wafer  410  by an electric force or clamping using a clamper. In a further embodiment of the invention, the chamber wall  408  is formed of hydrophilic materials. 
         [0022]    In an important aspect of the embodiment, a meshed inner cup  412  comprising a plurality of through holes  409  is provided between the wafer holder  402  and the chamber wall  408  in the chamber  401  of the scrubber. In the invention, the through holes  409  in the meshed inner cup  412  are cone-shaped. In more detail, an inner opening of each through hole  409  of the mashed inner cup  412  is larger than the outer opening. In an embodiment of the invention, the meshed inner cup  412  is formed of hydrophobic material, so that the meshed inner cup  412  can catches more water  406  released from the wafer  410  surface. Alternatively, the meshed inner cup  412  is formed of hydrophilic material, so that the meshed inner cup  412  can release water  406  sooner. The meshed inner cup  412  can spin around the spindle  404 . Rotation speed of the meshed inner cup  412  can be less than, the same as or greater than the rotation speed of the wafer  410  depending upon process conditions, such as water  406  quantity. Further, rotation speed of the meshed inner cup  412  can vary when the quantity or speed of the water  406  from the wafer  410  changes. The spinning mashed inner cup  412  can catch water  406  and release the water  406  via the through holes  409  in the mashed inner cup  412  to the chamber wall  408 . Therefore, the mashed inner cup  412  can catch and release water  406 , and the water  406  scattering back issue can be addressed. 
         [0023]    While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. It is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.