Patent Publication Number: US-2016240398-A1

Title: Wafer Holder

Description:
CLAIM OF PRIORITY 
     The present application claims priority from Taiwan Application No. 104104677, filed on Feb. 12, 2015 and entitled “WAFER HOLDER”, the contents of which are expressly incorporated herein by reference in their entirety. 
     BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The invention generally relates to a wafer holder, and more particularly to a wafer holder for preventing a wafer from rotating. 
     2. Description of Related Art 
       FIG. 1A  shows a cross-sectional view of a conventional wafer holder  100 , and  FIG. 1B  shows a wafer  140  processed using a conventional manufacturing process. The wafer holder  100  includes a holder main body  110  and a plurality of supporting members  120 . The supporting members  120  are disposed on an inner surface of the holder main body  110 . In the manufacturing process, the wafer  140  is placed face down on the supporting members  120 . Thus, as shown in  FIG. 1B , the wafer  140  might have pressure marks  142 A corresponding to top surfaces of the supporting members  120 . 
     However, as the wafer  140  needs to be kept in a high-temperature state during the manufacturing process, the wafer  140  is generally heated from a top opening  130  of a wafer holder  100 , and a reactive gas is applied to a surface of the wafer  140  for epitaxial growth. The wafer  140  rotates or moves in any direction due to thermal deformation or the impact effect of the reactive gas, and the surface of the wafer  140  may correspondingly have marks  142 B caused by an Epi film. Consequently, the usable surface area of the wafer  140  may be reduced. 
     A need has thus arisen to address defects of a conventional wafer holder. 
     SUMMARY 
     In view of the foregoing, embodiments of the disclosure provide a wafer holder to reduce or prevent a wafer from rotating or moving, e.g., in a random direction, and from incurring marks, e.g., pressure marks, during a manufacturing process of the wafer. The wafer holder may improve a production yield and increase a usable area of the wafer. 
     According to one embodiment of the disclosure, a wafer holder includes a holder main body, a supporting member, and a limiting member. The holder main body includes a through hole region. The supporting member includes a supporting main body and a plurality of supporting legs. The supporting main body is disposed on the through hole region, and the supporting legs are evenly attached to an inner surface of the supporting main body and configured to support a wafer. The limiting member is attached to the supporting main body and disposed between two adjacent supporting legs. The limiting member is opposite to a flat side of the wafer to prevent or restrict the wafer from rotating. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a cross-sectional view of a conventional wafer holder. 
         FIG. 1B  shows a wafer processed under conventional manufacturing conditions. 
         FIG. 2A  shows a partial perspective view of a wafer holder according to an embodiment of the disclosure. 
         FIG. 2B  shows a top view of the wafer holder of  FIG. 2A . 
         FIG. 2C  shows a view of a wafer disposed on the wafer holder of  FIG. 2A . 
         FIG. 2D  shows a view of an isothermal plate and a wafer both disposed on the wafer holder of  FIG. 2A . 
         FIG. 3A  shows a partial perspective view of a wafer holder according to another embodiment of the disclosure. 
         FIG. 3B  shows a view of a wafer disposed on the wafer holder of  FIG. 3A . 
     
    
    
     DETAILED DESCRIPTION 
     The description provided in reference to the following embodiments is not intended to limit the scope of the invention, which can be adapted for other applications. Although drawings are illustrated in detail, it is appreciated that aspects and features in the description or drawings may vary from that disclosed. For example, a characteristic or quantity of a component may differ or be greater or less than that disclosed absent an express restriction of the characteristic or quantity. 
       FIGS. 2A-2C  show sundry views of a wafer holder  200  according to an embodiment of the disclosure.  FIG. 2A  shows a partial perspective view of the wafer holder  200 ,  FIG. 2B  shows a top view of the wafer holder  200 , and  FIG. 2C  shows an additional view of the wafer holder  200  combined with a wafer  240 . As illustrated in  FIGS. 2A-2C , the wafer holder  200  includes a holder main body  210 , a supporting member  220 , and a limiting member  230 . The holder main body  210  has a through hole region  212 . The supporting member  220  includes a supporting main body  222  and a plurality of supporting legs  224 . The supporting main body  222  is disposed on the through hole region  212 , and the supporting legs  224  are evenly spaced and attached to an inner surface of the supporting main body  222 , in order to support the wafer  240 . The limiting member  230  is attached to the supporting main body  222  and disposed between two adjacent supporting legs  224 . Furthermore, the limiting member  230  is disposed opposite to a flat side  242  of the wafer  240 , in order to prevent or restrict the wafer  240  from rotating. Further, in one embodiment, any combination of the holder main body  210 , the supporting member  220 , and the limiting member  230  may be formed integrally, according to an actual design or need. 
     Each supporting leg  224  may have a first supporting surface  226 , which is configured to support the wafer  240 . The supporting main body  222  and the supporting legs  224  may be formed integrally, according to an actual design or need. In addition, the limiting member  230  may include a limiting main body  231 , and the limiting main body  231  may have a limiting surface  232 , which is opposite to the flat side  242  of the wafer  240 , for preventing or restricting the wafer  240  from rotating. 
     In the illustrated embodiment, the limiting member  230  may further include a supporting block  233 , which is located on a bottom end of the limiting surface  232  of the limiting main body  231 . The supporting block  233  has a top surface  234 , which is configured to support the wafer  240 . According to an aspect, the top surface  234  of the supporting block  233  may have substantially the same height level as the first supporting surfaces  226  of supporting legs  224 . Therefore, when the wafer  240  is disposed on the wafer holder  200 , the wafer  240  can be simultaneously disposed and supported on the first supporting surfaces  226  of the supporting legs  224  and on the top surface  234  of the supporting block  233 . 
     As depicted in  FIG. 2C , when the wafer  240  is influenced to outwardly move or expand, e.g., via thermal deformation or an impact effect of a reactive gas, the flat side  242  of the wafer  240  may abut against the limiting surfaces  332  of the limiting main body  231 . Hence, the wafer  240  may be hindered or prevented from rotation or movement, e.g., in any direction. In one embodiment, a gap between the limiting surface  232  and the flat side  242  of the wafer  240  is between 0.05 mm and 1 mm. Moreover, in the embodiment illustrated in  FIG. 2C , a length (L 1 ) of the limiting surface  232  is greater than a length (Lw) of the flat side  242  of the wafer  240 . The invention is not limited to the enumerated dimensions. For example, the length (L 1 ) of the limiting surface  232  can be adjusted to be less than or equal to the length (Lw) of the flat side  242  of the wafer  240 , according to an actual need, e.g., of a manufacturing process. 
       FIG. 2D  shows a view of an isothermal plate  250  and the wafer  240  both disposed on the wafer holder  200  of  FIG. 2A . As shown in  FIG. 2D , the wafer holder  200  can further include the isothermal plate  250 , and the isothermal plate  250  can be disposed on a second supporting surface  228  of the supporting main body  222  of the supporting member  220 . The second supporting surface  228  is above the first supporting surface  226 . Therefore, heating of the wafer  240  from the top of the wafer holder  200  may cause a gas thermal convection in the cavity between the isothermal plate  250  and the wafer  240 , and may result in a surface of the wafer  240  being relatively uniformly heated and a process yield being effectively improved. 
       FIG. 3A  shows a partial perspective view of a wafer holder  300  according to another embodiment of the disclosure, and  FIG. 3B  shows a view of a wafer  340  disposed on the wafer holder  300 . As shown in  FIGS. 3A and 3B , the limiting member  330  may include a plurality of limiting blocks  331 . The limiting blocks  331  are evenly disposed on the inner surface of the supporting main body  322 . Each limiting block  331  has a limiting surface  332 , which is opposite to a flat side  342  of the wafer  340 . The limiting blocks  331  may be located on the inner surface of the supporting main body  322  at substantially the same height. Accordingly, as the wafer  340  is influenced to move or expand, e.g., outwardly, such as by thermal deformation or an impact effect via a reactive gas, the flat side  342  of the wafer  340  will abut against the limiting surfaces  332  of the limiting blocks  331 , so that the wafer  340  cannot or has a diminished capacity to rotate or move in any direction. In one embodiment, a gap between the limiting blocks  331  and the flat side  342  of the wafer  340  may be between 0.05 mm to 1 mm. 
     Furthermore, as shown in  FIG. 3B , a gap (L 2 ) between every two adjacent limiting blocks  331  may be less than or equal to a length (Lw) of the flat side  342  of the wafer  340 . Thus, when the wafer  340  is outwardly expanded because of thermal deformation, the surfaces  332  of the limiting blocks  331  will abut against the flat side  342  of the wafer  340  to effectively limit rotation or displacement of the wafer  34 , so that pressure marks on the wafer  340  may be reduced or avoided. 
     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 invention, which is intended to be limited solely by the appended claims and their equivalents.