Abstract:
Manually operated wafer handlers are provided for handling and transporting semiconductor wafers. The wafer handlers contact the wafers only at the outer edges of the wafers, thereby preventing damage to the interior surfaces of the wafers on which integrated circuits are formed.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to wafer handlers for handling and transporting semiconductor wafers and, more particularly, to manually operated wafer handlers.  
         BACKGROUND OF THE INVENTION  
         [0002]    Wafer handlers are commonly used to transport wafers to and from wafer storage cassettes and between various wafer processing areas. Automated robotic wafer handlers are typically used for relatively large batch applications. Manually operated wafer handlers are often used in laboratory and small batch applications.  
           [0003]    One common type of wafer handler uses vacuum pressure to hold the wafers in place during transport. Such wafer handlers typically comprise a wafer contact surface having vacuum ports formed therein. The vacuum ports are in fluid communication with a vacuum source, such as a pump. The handlers typically comprise means to increase the strength of the vacuum applied at the vacuum ports to secure the wafer to the handler during transport of the wafers, and decrease the strength of the vacuum applied at the vacuum ports to release the wafer from the handler.  
           [0004]    Manually operated vacuum wafer handlers typically contact the wafers at the center or interior of the wafers. Central or interior support of the wafers by the handlers is considered necessary for stability during manual handling of the wafers. This central or interior contact, however, can leave marks or scratches on the interior surfaces of the wafers on which the integrated circuits are formed, thereby damaging the wafers. In addition, because the wafer handlers are intended to contact the wafers at the center or interior of the wafers, the wafer handlers must be slid alongside the wafers to reach the interior of the wafers. This can be difficult when the wafers are supported in standard wafer cassettes, in which the pitch or distance between the wafers is relatively small. Furthermore, because the wafer handlers must be slid between the wafers in the cassettes, it is often difficult to load and unload the wafers from the cassettes without scraping the wafers on the supports of the cassettes, thereby further damaging the wafers.  
         SUMMARY OF THE INVENTION  
         [0005]    The preferred embodiments of the present invention overcome the problems of the prior art by providing wafer handlers that contact the wafers only at the outer peripheral edge, or “exclusion zone,” of the wafers, thereby preventing damage to the interior surface of the wafers on which the integrated circuits, or structures therefor, are formed or to be formed.  
           [0006]    In accordance with one aspect of the present invention, an apparatus for manually transporting a semiconductor wafer is provided. The apparatus comprises a handle and a grip portion at an end of the handle. The grip portion is adapted to extend along a peripheral edge of the wafer and has an upper surface for supporting the wafer. The upper surface has a plurality of vacuum ports therein.  
           [0007]    In accordance with another aspect of the present invention, an apparatus for transporting a semiconductor wafer is provided. The apparatus comprises a handle and a grip portion at an end of the handle. The grip portion has a recessed area in an upper surface thereof. A plurality of vacuum ports are provided in the upper surface of the recessed area.  
           [0008]    In accordance with another aspect of the present invention, an apparatus for transporting a semiconductor wafer is provided. The apparatus comprises a handle and a grip portion having a plurality of vacuum ports therein. The vacuum ports generally lie on a circle having a diameter slightly less than a diameter of the wafer.  
           [0009]    In accordance with another aspect of the present invention, an apparatus for transporting a semiconductor wafer is provided. The apparatus comprises a handle and a grip portion at an end of the handle. The grip portion comprises a main body and a plurality of fingers extending from the main body. The grip portion has a plurality of vacuum ports in an upper surface thereof and a wafer support adjacent each of the vacuum ports. The wafer supports are arranged to contact the wafer at an edge of the wafer. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    These and other aspects of the invention will be readily apparent to the skilled artisan in view of the description below, the appended claims, and from the drawings, which are intended to illustrate and not to limit the invention, and wherein:  
         [0011]    [0011]FIG. 1 is a perspective view of one embodiment of a vacuum wand having certain features and advantages in accordance with the present invention;  
         [0012]    [0012]FIG. 2 is a top plan view of the vacuum wand of FIG. 1;  
         [0013]    [0013]FIG. 3 is a perspective view of another embodiment of a vacuum wand having certain features and advantages in accordance with the present invention; and  
         [0014]    [0014]FIG. 4 is a top plan view of the vacuum wand of FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    One embodiment of a wafer handler  20  having certain features and advantages in accordance with the present invention is illustrated in FIGS. 1 and 2. With reference to FIG. 1, in the illustrated embodiment, the wafer handler  20  generally comprises a handle  24  and a grip portion  28  at an end of the handle  24 . Note that “handle,” as used herein, refers to a part suitable for gripping by a human hand and free at one end such that the wafer handler  20  can be manually employed. The grip portion  28  includes a main body  32  that extends in a direction generally perpendicular to the handle  24  and a plurality of fingers  36  that extend generally parallel to the handle  24  from the main body  32 . In the illustrated embodiment, the grip portion  28  includes two fingers  36 , one at each side of the main body  32 .  
         [0016]    The wafer handler  20  preferably is generally planar and is relatively thin to facilitate sliding the handler  20  between wafers in a standard wafer cassette. The width of the grip portion  28  preferably is slightly less than the distance between the supports of the cassette that extend beneath the edges of the wafers to support the wafers. In the illustrated embodiment, the wafer handler  20  is configured to transport 300 mm wafers. Accordingly, the width of the grip portion  28  between the outer edges of the fingers  36  is preferably less than about 260 mm, and in the illustrated embodiment is 150 mm. Those skilled in the art will appreciate, however, that the optimal size of the grip portion  28  will depend on the diameter of the wafers to be transported with the handler  20 .  
         [0017]    With reference to FIG. 1, in the illustrated embodiment, the wafer handler  20  comprises a top member  40  and a bottom member  42  which is bonded or otherwise secured to the top member  40 . As illustrated in FIG. 2, a gas passage  46  is provided through the handler  20  between the top and bottom members  40 ,  42 . The gas passage  46  can be created, for example, by forming a groove in either the top member  40  or the bottom member  42  prior to securing the top and bottom members  40 ,  42  together. The gas passage  46  extends through the handle  24  of the wafer handler  20  and splits into two branches  52  at the main body  32  of the grip portion  28 . The branches  52  extend through the fingers  36  of the grip portion  28 .  
         [0018]    With reference to FIG. 2, vacuum ports  60  are provided in the grip portion  28  of the wafer handler  20 . In the illustrated embodiment, the wafer handler  20  includes three vacuum ports  60 . A first vacuum port  60  is provided in the main body  32  of the grip portion  28 . Second and third vacuum ports  60  are provided near the ends of the fingers  36 . The vacuum ports  60  comprise openings that extend from the gas passage  46  through the top member  40  of the handler  20 .  
         [0019]    As is apparent from FIG. 2, in the illustrated embodiment, the vacuum ports  60  are arranged to generally lie on a circle C 1  having a diameter less than the diameter of the wafers to be transported with the handler  20 . Preferably, the diameter of the circle C 1  is between about 0.2 mm and 10 mm less than the diameter of the wafers to be transported. More preferably, the diameter of the circle C 1  is between about 0.4 mm and 5 mm less than the diameter of the wafers to be transported. Thus, if the wafer handler  20  is configured to transport 300 mm wafers, as in the illustrated embodiment, the diameter of the circle C 1  is preferably between about 290 mm and 299.8 mm, and more preferably between about 295 mm and 299.6 mm.  
         [0020]    As illustrated in FIG. 2, a wafer support  68  is provided adjacent each of the vacuum ports  60 . The wafer supports  68  extend above the upper surface of the top member  40  and preferably surround the vacuum ports  60 . The supports  68  can be formed integrally with the top member  40  or bonded to the upper surface of the top member  40 , and are preferably either made of, or coated with, TEFLON®, VESPEL®, or a similar low-friction material. The wafer supports  60  are arranged so that, when a wafer is properly situated on the grip portion  28 , the wafer supports  68  contact only the peripheral edge of the wafer. Preferably, the wafer supports  68  are arranged to contact the wafer no more than about 5 mm from the edge of the wafer, and more preferably no more than about 3 mm from the edge of the wafer.  
         [0021]    A vacuum line (not shown) preferably is connected to the handle  24  at a rear of the gas passage  46 . The vacuum line extends between the wafer handler  20  and a pump (not shown) or other vacuum source. The vacuum ports  60  are thus in fluid communication with the pump via the gas passage  46  and the vacuum line.  
         [0022]    In the wafer handler  20  of FIGS. 1 and 2, a vacuum release opening  80  is provided near an end of the handle  24  adjacent the grip portion  28 . The vacuum release opening  80  extends into the gas passage  46  through the top member  40  of the handler  20 . As will be appreciated by those skilled in the art, the strength of the vacuum delivered to the vacuum ports  60  is increased when the release opening  80  is obstructed, for example, by the thumb of the operator, and decreased when the release opening  80  is unobstructed. Thus, when the operator desires to grasp a wafer, the grip portion  28  of the handler  20  is slid beneath the wafer with the release opening  80  unobstructed so that the wafer supports  68  are positioned at the peripheral edge of the wafer. The release opening  80  is then covered, for example, by the thumb of the operator. Alternatively, the wafer handler  20  may be equipped, for example, with a cover (not shown) that the operator can slide, rotate or lower onto the release opening  80  to obstruct the opening  80 . When the release opening  80  is covered, the vacuum applied at the vacuum ports  60  retains the wafer against the wafer supports  68 . The wafer can then be safely transported with the wafer handler  20 . To release the wafer from the handler  20 , the vacuum release opening  80  is uncovered and the grip portion  28  is slid out from beneath the wafer.  
         [0023]    Because the wafer supports  68  of the handler  20  of FIGS. 1 and 2 are raised above the upper surface of the top member  40 , the wafers do not contact the upper surface of the top member  40 . The wafers are contacted only by the wafer supports  68 . Since the wafer supports  68  are arranged to contact only the edge exclusion zone of the wafer, damage to the interior of the wafer, on which the integrated circuits are formed or to be formed, is prevented.  
         [0024]    With reference now to FIGS. 3 and 4, a second embodiment of a wafer handler  100  having certain features and advantages in accordance with the present invention is illustrated. The wafer handler  100  of FIGS. 3 and 4 generally comprises a handle  104  and a grip portion  108  at an end of the handle  104 .  
         [0025]    A recessed area  110  is provided at an end of the grip portion  108 . In the illustrated embodiment, the recessed area  110  comprises an arc-shaped surface for supporting the wafers. A wall  116  is formed where the recessed area  110  meets the rest of the grip portion  108 . The width of the recessed area  110  between the wall  116  and the side of the recessed area  110  opposite the wall  116  is preferably between about 5 mm and 10 mm. Accordingly, when a wafer is positioned on the recessed area  110  so that the edge of the wafer abuts the wall  116 , the recessed area  110  preferably extends inwardly from the edge of the wafer towards the center of the wafer less than about 10 mm.  
         [0026]    Preferably, the recessed area  110  is sized to extend along the edges of the wafers about 90°. The grip portion  108  preferably is as long as possible without interfering with the sides of the wafer cassette during loading or removal of the wafers. As will be appreciated by those skilled in the art, as the length of the recessed area  110  is decreased, the width of the recessed area  110  and/or the strength of the vacuum required to hold the wafer in place at the end of the wafer handler  100  are increased. Conversely, as the width of the recessed area  110  is decreased, the length of the recessed area  110  and/or the strength of the vacuum required to hold the wafer in place are increased.  
         [0027]    Like the wafer handler  20  of FIGS. 1 and 2, the wafer handler  110  illustrated in FIGS. 3 and 4 preferably comprises a top member  124  and a bottom member  126  which is bonded or otherwise secured to the top member  124  (see FIG. 3). As illustrated in FIG. 4, a gas passage  132  is provided through the handler  100  between the top and bottom members  124 ,  126 , preferably by forming a groove in either the top member  124  or the bottom member  126  prior to securing the top and bottom members  124 ,  126  together. The gas passage  132  extends through the handle  104  of the wafer handler  100  and through the grip portion  108  to the recessed area  110 .  
         [0028]    With reference to FIG. 4, a plurality of vacuum ports  140  are provided in the recessed area  110  of the grip portion  108 . In the illustrated embodiment, five vacuum ports  140  are spaced apart along the recessed area  110 . Those skilled in the art will appreciate, however, that a greater or lesser number of vacuum ports  140  may be provided, as necessary, to hold the wafers in place against the recessed area  110 . The vacuum ports  140  comprise openings that extend into the gas passage  132  through the top member  124  of the handler  100 . In the illustrated embodiment, the gas passage widens towards the recessed area  110  to communicate with all of the vacuum ports  140 . Alternatively, however, the gas passage  132  may be divided into branches near the recessed area  110 , so that each of the branches communicates with only one or some portion of the vacuum ports  140 .  
         [0029]    As in the embodiment of FIGS. 1 and 2, the vacuum ports  140  of the wafer handler  100  of FIGS. 3 and 4 preferably are arranged to generally lie on a circle C 2  having a diameter less than or equal to the diameter of the wafers to be transported with the handler  100 . Preferably, the diameter of the circle C 2  is between about 0.2 mm and 10 mm less than the diameter of the wafers to be transported. More preferably, the diameter of the circle C 2  is between about 0.4 mm and 5 mm less than the diameter of the wafers to be transported. Accordingly, if the wafer handler  100  is configured to transport 300 mm wafers, as in the illustrated embodiment, the diameter of the circle C 2  is preferably between about 290 mm and 299.8 mm, and more preferably between about 295 mm and 299.6 mm.  
         [0030]    As illustrated in FIG. 4, a wafer support  150  is provided adjacent each of the vacuum ports  140 . The wafer supports  150  extend above the upper surface of the recessed area  110  and preferably surround the vacuum ports  140 . The supports  150  can be formed integrally with the recessed area  110  or bonded to the upper surface of the recessed area  110 , and are preferably either made of, or coated with, TEFLON®, VESPEL®, or a similar low-friction material. The wafer supports  150  are arranged so that, when a wafer is properly situated on the recessed area  110 , the wafer supports  150  contact only the peripheral edge of the wafer. Preferably, the wafer supports  150  are arranged to contact the wafer no more than about 5 mm from the edge of the wafer, and more preferably no more than about 3 mm from the edge of the wafer.  
         [0031]    A vacuum line (not shown) preferably is connected to the handle  104  of the wafer handler  110  at a rear of the gas passage  132 . The vacuum line extends between the wafer handler  100  and a pump (not shown) or other vacuum source. The vacuum ports  140  are thus in fluid communication with the pump via the gas passage  132  and the vacuum line.  
         [0032]    With reference still to FIG. 4, a vacuum release opening  152  is provided near an end of the handle  104  adjacent the grip portion  108 . The vacuum release opening  152  extends into the gas passage  132  through the top member  124  of the handler  100 . When the operator desires to grasp a wafer, the recessed area  110  of the grip portion  108  is slid beneath the wafer with the release opening  152  unobstructed until the wall  116  between the recessed area  110  and the rest of the grip portion  108  abuts the edge of the wafer. The wall  116  thus helps to ensure that the wafer handler  100  is properly positioned with respect to the wafer. The vacuum release opening  152  is then covered, for example, by the thumb of the operator. Alternatively, the wafer handler  100  may be equipped, for example, with a cover (not shown) that the operator can slide, rotate or lower onto the release opening  152  to obstruct the opening  152 . When the release opening  152  is obstructed, the wafer is supported on the recessed area  110  while the vacuum applied at the vacuum ports  140  retains the wafer in place. The wafer can then be safely transported with the wafer handler  100 . To release the wafer from the handler  100 , the release opening  152  is uncovered and the recessed area  110  is slid out from beneath the wafer. Because the recessed area  110  is relatively narrow, only the edge exclusion zone of the wafer is contacted by the wafer handler  100 . Damage to the interior of the wafer is thereby prevented.  
         [0033]    In standard wafer cassettes or front-opening unified pods (“FOUPs”), the front portions of the wafers are easily accessible. One advantage of the wafer handler  100  of FIGS. 3 and 4 is that only the recessed area  110  of the grip portion  108 , which is relatively narrow, is slid beneath a wafers to support the wafer. Because the wafer handler  100  is slid beneath only the edge on one side of the wafer, the likelihood of the handler  100  marking or scratching the interior surface of the wafer is eliminated. Furthermore, since the recessed area  110  preferably extends only about 90° around the edge of the wafer, the wafer handler  100  can easily access the front portions of the wafers in standard wafer cassettes or FOUPs.  
         [0034]    It should be noted that certain objects and advantages of the invention have been described above for the purpose of describing the invention and the advantages achieved over the prior art. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.  
         [0035]    Moreover, although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. It is further contemplated that various combinations and sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.