Abstract:
A wafer guide for supporting at least one semiconductor wafer during a cleaning process, includes side panels having a plurality of side fixing grooves on an upper surface thereof for stabilizing the at least one semiconductor wafer and for maintaining a sufficient distance between a surface of the at least one semiconductor wafer and an adjacent surface; a center panel having a plurality of center fixing grooves on the upper surface thereof for supporting the at least one semiconductor wafer, each of the plurality of center fixing grooves having inner walls, wherein a contact line is formed on each of the inner walls of the center fixing grooves, and wherein the center panel is positioned between the pair of side panels; and a pair of fixing plates, one of the pair of fixing plates being fixedly attached at each end of the center panel and the pair of side panels.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a wafer guide and a cleaning apparatus having the same that is capable of reducing a contact area between the wafer guide and a semiconductor wafer, thereby preventing residue from remaining on the semiconductor wafer after a cleaning process.  
           [0003]    2. Description of the Related Art  
           [0004]    In general, to fabricate a semiconductor device, a plurality of layers such as an oxide layer, a nitride layer and a metal layer are formed on a semiconductor wafer and patterned by means of an etching process. After the etching process is completed, a cleaning process is performed. During the cleaning process, the semiconductor wafer is dipped into a bath filled with a cleaning solution to remove unnecessary films, such as a photoresist film or an etching mask film. During the cleaning process, a plurality of wafers may be mounted on the wafer guide and simultaneously cleaned. The wafer guide prevents the plurality of wafers from falling over and positions the wafers at sufficient intervals during the cleaning process.  
           [0005]    Thus far, various attempts have been made to produce a wafer guide capable of preventing residue from remaining on a wafer, in particular at a contact portion of the wafer, i.e., the portion of the wafer with which the wafer guide is in contact.  
           [0006]    [0006]FIG. 1 illustrates a conventional wafer guide according to the prior art. The wafer guide  2  includes a pair of side panels  10   a  and  10   b , a center panel  12 , which is located between the side panels  10   a  and  10   b , and a pair of fixing plates  14   a  and  14   b . Each one of the fixing plates  14   a ,  14   b  is located at an end of the side panels  10   a ,  10   b  and the center panel  12  and is fixedly connected thereto. Each of the side panels  10   a  and  10   b  has a plurality of V-shaped side fixing grooves  11   a  and  11   b , respectively, on an upper surface thereof to position a wafer on the wafer guide. The center panel  12  has a plurality of Y-shaped center fixing grooves  13  on an upper surface thereof. Inner walls of the center fixing grooves  13  form a contact plane to contact a wafer  18 . Each of the fixing plates  14   a  and  14   b  has a protrusion  16   a  and  16   b , respectively, outwardly extending from a top end thereof.  
           [0007]    The side fixing grooves  11   a  and  11   b  of the side panels  10   a  and  10   b  do not contact a thin film formed on a surface of the wafer  18  and serve only to stabilize the wafer  18 , whereas the center fixing grooves  13  contact a thin film on the surface of the wafer  18  and primarily support the wafer  18 . Prior to the cleaning process a plurality of wafers  18  having a thin film  19  on the surface thereof are inserted into the wafer guide  2 . The plurality of wafers  18  are inserted into the side fixing grooves  11   a  and  11   b  and the center fixing grooves  13 . During the cleaning process, the wafer guide  2  is placed in a bath and the bath is filled with a cleaning solution. The purpose of the cleaning solution is to remove the thin film  19  on the wafers  18 . The thin films  19  are removed by a chemical reaction between the cleaning solution and the thin films  19 . Finally, after the cleaning process is complete, the wafer guide  2  is removed from the bath.  
           [0008]    [0008]FIGS. 2A and 2B illustrate cross-sectional views taken along sectional lines II a -II a  and II b -II b , respectively, of FIG. 1. As shown in FIG. 2A, in view of the manner in which the wafer  18  is stabilized by the side fixing grooves  11   a ,  11   b , no residue from the thin film remain on that portion of the wafer. Specifically, the surface of the wafer  18  having the thin film  19  thereon and the side fixing grooves  11   a ,  11   b  are not in contact so the cleaning solution may remove the thin film  19 . As illustrated in FIG. 2B, a portion of the wafer  18  is in contact with the center fixing grooves  13  thereby allowing a residue of the thin film  19  to remain on that portion of the wafer. This residue is caused by the fact that the cleaning solution is not able to contact sufficiently that portion of the thin film.  
           [0009]    The reason the residue remains on the wafer is detailed with reference to FIGS. 3A through 3C. FIGS. 3A through 3C illustrate top views of the wafer  18  having a thin film  19  formed thereon in contact with the center fixing grooves  13  of the wafer guide  2 .  
           [0010]    As shown in FIG. 3A, the wafer  18  is vertically inserted into the center fixing grooves  13  of the center panel  12 . Next, the wafer  18  having the thin film  19  thereon is dipped into the bath filled with the cleaning solution.  
           [0011]    Next, as shown in FIG. 3B, most of the thin film  19  is removed by chemically reacting with the cleaning solution. A portion of the thin film  19 ′, however, remains on the wafer  18  where the thin film  19  on the wafer  18  is in contact with an inner wall of the center fixing grooves  13  of the center panel  13  of the wafer guide  2 .  
           [0012]    Next, as shown in FIG. 3C, a further portion of the remaining thin film  19 ′ is removed at both sides thereof through isotropical etching by the cleaning solution. A residue of the thin film  19 ″, however, still remains at a center portion of the center fixing groove  13  because the cleaning solution is not able to permeate into that area of the thin film.  
         SUMMARY OF THE INVENTION  
         [0013]    It is therefore a feature of an embodiment of the present invention to provide a wafer guide and a cleaning apparatus having the same that is capable of preventing residue from remaining on a wafer after a cleaning process is completed.  
           [0014]    According to an embodiment of the present invention, there is provided a wafer guide for supporting at least one semiconductor wafer during a cleaning process, including a pair of side panels, each side panel having two ends, an upper surface, and a plurality of side fixing grooves on the upper surface thereof for stabilizing the at least one semiconductor wafer and for maintaining a sufficient distance between a surface of the at least one semiconductor wafer and an adjacent surface; a center panel having two ends, an upper surface, and a plurality of center fixing grooves on the upper surface thereof for supporting the at least one semiconductor wafer, each of the plurality of center fixing grooves having inner walls, wherein a contact line is formed on each of the inner walls of the center fixing grooves, and wherein the center panel is positioned between the pair of side panels; and a pair of fixing plates, one of the pair of fixing plates being fixedly attached at each end of the center panel and the pair of side panels. The contact line of the inner walls of each of the plurality of center fixing grooves may be formed by the inner walls having a rounded shape or a triangular prism shape. An upper surface of each of the plurality of center fixing grooves is sloped down toward the center thereof at an inclination of between about 20-45°. The side fixing grooves may be V-shaped.  
           [0015]    According to another embodiment of the present invention, there is provided a wafer guide for supporting at least one semiconductor wafer during a cleaning process, including a plurality of panels, each panel having two ends, an upper surface, and a plurality of grooves on the upper surface thereof and being separated from each other, wherein each of the plurality of grooves has inner walls and the plurality of grooves of at least one of the plurality of the panels forms a contact line on the inner walls thereof to contact the at least one semiconductor wafer; and a pair of fixing plates attached to each of the panels at both ends thereof.  
           [0016]    According to yet another embodiment of the present invention, there is provided a cleaning apparatus having a wafer guide for supporting at least one semiconductor wafer, the wafer guide including a pair of side panels, each side panel having two ends and a plurality of side fixing grooves at an upper surface thereof for stabilizing the at least one semiconductor wafer, the pair of side panels being separated from each other; a center panel having two ends and a plurality of center fixing grooves at an upper surface thereof for supporting the at least one semiconductor wafer, each of the plurality of center fixing grooves having inner walls, wherein a contact line is formed on each of the inner walls of the center fixing grooves by either rounding the inner walls or shaping the inner walls to descend toward the center from both side edges, and wherein the center panel is positioned between the pair of side panels; and a pair of fixing plates, one of the pair of fixing plates being fixedly attached at each end of the center panel and the pair of side panels. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    The above and other features and advantages of the present invention will become more apparent upon review of a detailed description of preferred embodiments thereof with reference to the attached drawings in which:  
         [0018]    [0018]FIG. 1 illustrates a perspective view of a conventional wafer guide in accordance with the prior art;  
         [0019]    [0019]FIG. 2A illustrates a cross-sectional view taken along sectional line IIA-IIA of FIG. 1;  
         [0020]    [0020]FIG. 2B illustrates a cross-sectional view taken along sectional line IIB-IIB of FIG. 1;  
         [0021]    [0021]FIGS. 3A through 3C illustrate top views of a center fixing groove of a wafer guide having a wafer therein;  
         [0022]    [0022]FIG. 4 illustrates a perspective view of a wafer guide in accordance with a first preferred embodiment of the present invention;  
         [0023]    [0023]FIG. 5 illustrates a perspective view of a wafer guide in accordance with a second preferred embodiment of the present invention;  
         [0024]    [0024]FIG. 6 illustrates a schematic view of a cleaning apparatus in accordance with the present invention;  
         [0025]    [0025]FIGS. 7A through 7C illustrates views for explaining an operation of a wafer guide in accordance with the first preferred embodiment of the present invention; and  
         [0026]    [0026]FIGS. 8A through 8C illustrates views for explaining an operation of a wafer guide in accordance with the second preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]    Korean Patent Application No. 2001-78657, filed on Dec. 12, 2001, and entitled: “Wafer Guide and Cleaning Apparatus Having the Same,” is incorporated by reference herein in its entirety.  
         [0028]    [0028]FIG. 4 illustrates a perspective view of a wafer guide in accordance with a first preferred embodiment of the present invention. The wafer guide  4  includes a pair of side panels  30   a  and  30   b , a center panel  32  and a pair of fixing plates  34   a  and  34   b . The side panels  30   a  and  30   b  and the center panel  32 , which is located between the side panels  30   a  and  30   b , are fixedly attached to the fixing plates  34   a  and  34   b  at both ends.  
         [0029]    Each of the side panels  30   a  and  30   b  has a plurality of V-shaped side fixing grooves  31   a  and  31   b  on an upper surface thereof for stabilizing a wafer  38 . In addition, the side panels  30   a  and  30   b  maintain a sufficient distance between a surface of the wafer  38  and an adjacent surface, such as another wafer, if present, or the fixing plates  34   a  and  34   b . The center panel  32  has a plurality of Y-shaped center fixing grooves  33  on an upper surface thereof for supporting the wafer  38 . The center fixing grooves  33  have inner walls formed with a rounded shape to establish a contact line  33   a , as opposed to a contact plane. Accordingly, the center fixing grooves  33  of the wafer guide  4  only contact the wafer  38  at the contact line, so that a portion of the wafer  38  in contact with the wafer guide  4  is minimized.  
         [0030]    The side panels  30   a  and  30   b , and the side fixing grooves  31   a  and  31   b  thereof stabilize the wafers so the wafers are not separated from the wafer guide  4 . The center panel  32  and the center fixing grooves  33  provide the primary support for the wafer  38 . Further, an upper surface of the center fixing grooves  33  descends from both edges to the center thereof at an inclination of between about 20-45° so that the wafers may be smoothly slid into the center fixing grooves  33  along a sloped surface.  
         [0031]    Each of the fixing plates  34   a  and  34   b  has a protrusion  36   a  and  36   b  outwardly extending from a top end thereof. In operation, the wafer guide  4  is removably attached to a bath of a cleaning apparatus by resting the protrusions  36   a  and  36   b  on a top of the bath. Preferably, the wafer guide  4  is made of quartz or Teflon®.  
         [0032]    [0032]FIG. 5 illustrates a wafer guide  6  in accordance with a second preferred embodiment of the present invention. The wafer guide  6  includes a pair of side panels  40   a  and  40   b , a center panel  42  and a pair of fixing plates  44   a  and  44   b . The side panels  40   a  and  40   b  and the center panel  42 , which is located between the side panels  40   a  and  40   b , are attached to the fixing plates  44   a  and  44   b  at both ends.  
         [0033]    Each of the side panels  40   a  and  40   b  has a plurality of V-shaped side fixing grooves  41   a  and  41   b  on an upper surface thereof for stabilizing a wafer  48 . In addition, the side panels  40   a  and  40   b  maintain a sufficient distance between a surface of the wafer  48  and an adjacent surface, such as another wafer, if present, or the fixing plates  44   a  and  44   b . The center panel  42  has a plurality of Y-shaped center fixing grooves  43  on an upper surface thereof for primarily supporting the wafer  48 . The center fixing grooves  43  have inner walls formed in a triangular prism shape to establish a contact line  43   a , as opposed to a contact plane. More specifically, each of the inner walls are angled from the center to both side edges. Accordingly, the center fixing grooves  43  of the wafer guide  6  only contact the wafer  48  at the contact line  43   a , so that a portion of the wafer  48  in contact with the wafer guide  6  is minimized.  
         [0034]    The side panels  40   a  and  40   b , and the side fixing grooves  41   a  and  41   b  thereof stabilize the wafers so the wafers are not separated from the wafer guide  6 . The center panel  42  and the center fixing grooves  43  provide the primary support for the wafer  48 . Further, an upper surface of the center fixing grooves  43  descends from both edges to the center thereof at an inclination of between about 20-45° so that the wafers may be smoothly slid into the center fixing grooves  43  along a sloped surface.  
         [0035]    The fixing plates  44   a  and  44   b  have a protrusion  46   a  or  46   b  outwardly extending from a top end thereof. In operation, the wafer guide  6  is removably attached to a bath of a cleaning apparatus by resting the protrusions  36   a  and  36   b  on a top of the bath, Preferably, the wafer guide  6  is made of quartz or Teflon®.  
         [0036]    [0036]FIG. 6 illustrates a schematic view of a cleaning apparatus having a wafer guide in accordance with the present invention. As shown in FIG. 6, the wafer guide ( 4  or  6 ) having a plurality of wafers mounted therein is inserted into an interior bath  50  containing a cleaning solution. At this time, the protrusions (not shown in FIG. 6 but shown in FIG. 4 or  5 , see  36   a  and  36   b ,  46   a  and  46   b ) are rested on both top ends of the interior bath  50 .  
         [0037]    An exterior bath  52  is installed outside the interior bath to surround an upper part of the interior bath  50  to receive and store the cleaning solution that may overflow from the interior bath  50 . Bottoms of the exterior bath  52  and the interior bath  50  are connected to each other by a circulation pipe  54  interposed by a pump  56  and a filter  58 . A drain pipe  60  is branched off from the circulation pipe  54  between the pump  56  and the filter  58 .  
         [0038]    After the cleaning solution stored in the interior bath  50  overflows to the exterior bath  52 , the pump  56  operates to filter the overflowed cleaning solution through the filter  58  and then to return the overflowed cleaning solution to the interior bath  50 . The cleaning solution is continuously filtered by a circulation operation. When the cleaning solution becomes sufficiently degraded in quality so as to be unusable, a valve  62  is opened and the used cleaning solution stored in the interior bath  50  and the exterior bath  52  are drained. Supply of new cleaning solution to the baths  50  and  52  follows.  
         [0039]    [0039]FIGS. 7A through 7C illustrate top views of the wafer guide in which the wafers  38  are mounted during a cleaning process in accordance with the first preferred embodiment of the present invention.  
         [0040]    First, as shown in FIG. 7A, the wafer  38  having a thin film  39  on a surface thereof is received in the center fixing groove  33  of the center panel  32  of the wafer guide. At this time, only a small portion of the thin film  39  on the wafer  38  is in contact with the inner wall of the center fixing groove  33 , in particular at the contact line  33   a , because of the rounded shape of the inner walls of the center fixing grooves  33 .  
         [0041]    Next, as shown in FIG. 7B, most of the thin film  39  on the wafer  38  is removed by chemically reacting with the cleaning solution stored in interior bath  50 . More specifically, the thin film  39  is removed from all areas except for at the contact line  33   a . At the contact line  33   a , a residue of thin film  39 ′ remains.  
         [0042]    Finally, as shown in FIG. 7C, the remaining thin film ( 39 ′ in FIG. 7B) is completely removed by an isotropic etching characteristic of the cleaning solution, so that there no residue remains on the wafer  38 . The cleaning solution is able to remove completely the residue of the thin film  39 ′ because the contact area is sufficiently small to allow the cleaning solution to etch to the center of the contact line  33   a.    
         [0043]    [0043]FIGS. 8A through 8C illustrate top views of the wafer guide in which the wafers  48  are mounted during a cleaning process in accordance with the second preferred embodiment of the present invention.  
         [0044]    First, as shown in FIG. 8A, the wafer  48  having a thin film  49  on a surface thereof is received in the center fixing groove  43  of the center panel  42  of the wafer guide. At this time, only a small portion of the thin film  49  on the wafer  48  is in contact with the inner wall of the center fixing groove  43 , in particular at the contact line  43   a , because of the triangular prism shape of the inner walls of the center fixing grooves  43 .  
         [0045]    Next, as shown in FIG. 8B, most of the thin film  49  on the wafer  48  is removed by chemically reacting with the cleaning solution stored in interior bath  50 . More specifically, the thin film  49  is removed from all areas except for at the contact line  43   a . At the contact line  43   a , a residue of thin film  49 ′ remains.  
         [0046]    Finally, as shown in FIG. 8C, the remaining thin film ( 49 ′ in FIG. 8B) is completely removed by an isotropic etching characteristic of the cleaning solution, so that no residue remains on the wafer  48 . The cleaning solution is able to remove completely the residue of the thin film  49 ′ because the contact area is sufficiently small to allow the cleaning solution to etch to the center of the contact line  43   a.    
         [0047]    As described above, the present invention provides a wafer guide and a cleaning apparatus having the same that is capable of preventing a residue from remaining on a surface of a wafer after a cleaning process by minimizing a contact area between the wafer guide and the wafer.  
         [0048]    Preferred embodiments of the present invention have been disclosed herein and, although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.