Abstract:
The invention relates to apparatus for wafer transportation. A handle assembly is engageable with a wafer transfer cassette and has a grip which allows for movement of the wafer transfer cassette. The handle assembly is profiled so as not to interfere with insertion of the cassette into certain apparatuses. The handle assembly is also profiled to allow for easy detachment when the wafer transfer cassette is in such an apparatus, and easy attachment to the wafer transfer cassette.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]    Priority is claimed from U.S. Provisional patent application Ser. No. 60/242,473 filed on Oct. 24, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1). Field of the Invention  
           [0003]    This invention relates to an apparatus for wafer transportation and an apparatus for handling a wafer.  
           [0004]    2). Discussion of Related Art  
           [0005]    Wafer transfer cassettes are used for transferring wafers from one location to another in a semiconductor fabrication environment. A plurality of wafers are downwardly inserted between sidewalls of a wafer transfer cassette. A base of the wafer transfer cassette supports a lower periphery of each wafer. Septa separate the wafers from one another so that they are spaced in an axial direction.  
           [0006]    A handle assembly is then attached to the wafer transfer cassette. The handle assembly includes a grip which can be used for manually moving the wafer transfer cassette from location to location. Conventional handle assemblies do not allow for easily inserting a wafer transfer cassette into certain apparatuses. Conventional wafer transfer cassettes also do not provide for easy engagement with or disengagement from a wafer transfer cassette, especially when the wafer transfer cassette is located within certain apparatuses.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The invention is further described by way of examples with reference to the accompanying drawings wherein:  
         [0008]    [0008]FIG. 1 is a perspective view of an apparatus for wafer transportation, according to an embodiment of the invention;  
         [0009]    [0009]FIG. 2A is a side view illustrating a wafer transfer cassette and a handle assembly before engagement;  
         [0010]    [0010]FIG. 2B is a view similar to FIG. 1A after the handle assembly is moved towards the wafer transfer cassette;  
         [0011]    [0011]FIG. 2C is a view similar to FIG. 2B after the handle assembly is moved in an upward direction;  
         [0012]    [0012]FIG. 2D is a view similar to FIG. 2C after the handle assembly is further elevated;  
         [0013]    [0013]FIG. 3 is an end view of an apparatus for handling a wafer, according to an embodiment of the invention, which includes the apparatus of FIG. 1;  
         [0014]    [0014]FIG. 4A is a view similar to FIG. 2D, illustrating how the wafer transfer cassette and handle assembly are inserted into a rotor of the apparatus shown in FIG. 3;  
         [0015]    [0015]FIG. 4B is a view similar to FIG. 4A after the handle assembly is moved in a downward direction;  
         [0016]    [0016]FIG. 4C is a view similar to FIG. 4B after the handle assembly is moved away from the wafer transfer cassette; and  
         [0017]    [0017]FIG. 5 is a perspective view of an apparatus for wafer transportation, according to another embodiment of the invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    [0018]FIG. 1 of the accompanying drawings illustrates an apparatus  20  for wafer transportation, according to an embodiment of the invention, which includes a wafer transfer cassette  22 , and a handle assembly  24 .  
         [0019]    The wafer transfer cassette  22  includes first and second sidewalls  26  and  28 , first and second endwalls  30  and  32 , a base  34 , and septa  36 . The sidewalls  26  and  28  and the endwalls  30  and  32  extend upward from the base  34 . The septa  36  are located on inner surfaces of the sidewalls  26  and  28  and an upper surface of the base  34 . Rail supports  38  extend downwardly from a lower surface of the base  34 .  
         [0020]    In use, wafers are downwardly inserted into the transfer cassette  22 . Each wafer has a left edge against the sidewall  26 , a right edge against the sidewall  28  and a lower edge supported by the base  38 . The sidewalls  26  and  28  may for example be spaced from one another by about six inches, thereby allowing for wafers having diameters of six inches to be inserted between the sidewalls  26  and  28 . The wafers are spaced from one another in a direction of an axis  40 . The wafers are alternated by the septa  36 . Each wafer is supported by two of the septa  36  on opposing sides of the wafer, and each septa  36  supports two wafers on the opposing sides of the septa  36 .  
         [0021]    The endwall  30  has lift formations  42  and  44  formed on opposing sides thereof. The endwall  30  together with the lift formations  42  and  44  form a lift structure which is secured to the sidewalls  26  and  28 . The lift formation  42  extends to the left away from the axis  40  from a corner where the endwall  30  and the sidewall  26  meet. Similarly, the lift formation  44  extends to the right away from the axis  40  from a corner where the end wall  30  and the sidewall  28  meet. Each formation  42  and  44  has a respective lower surface  46 .  
         [0022]    The handle assembly  24  includes a grip  50  and an engagement structure  52 . The engagement structure  52  includes a flange  54  and engagement formations  56  and  58 . The flange  54  is shown in a vertical orientation.  
         [0023]    A connection block  60  is secured to the flange  54 . The grip  50  is secured to the connection block  60 . The connection block  60  extends horizontally away from the flange  54  and the grip  50  extends downwardly and away from the flange  54 . The grip  50  has an outer surface which can easily be held in a hand of the person. The grip  50  may be roughened or be coated with a material which reduces the likelihood of slip out of a hand of a person.  
         [0024]    The formations  56  and  58  extend from the flange  54  to a side of a flange  54  opposing the grip  50 . The formation  56  is located on the left of the grip  50  and the formation  58  is located on the right of the grip  50 . Each formation  56  or  58  has a respective slot  64  formed downwardly into an upper surface thereof and terminating in a base surface  66 .  
         [0025]    Stands  68  extend downwardly from a lower edge of the flange  54 . Lower edges of the stands  68  are located at a same elevation of a lower end of the grip  50  so that the handle assembly can be located on a horizontal surface with the flange  54  vertically oriented.  
         [0026]    FIGS.  2 A-D illustrate how the handle assembly  24  is used to engage with and elevate the wafer transfer cassette  22 . As shown in FIG. 2A, the wafer transfer cassette  22  is loaded with wafers  70 . Because the wafers  70  are circular, the upper edges thereof are located six inches above the base  34  of the wafer transfer cassette  22 . Lower surfaces of the rail supports  38  are located on a horizontal surface  72 . Lower surfaces of the stands  68  are also located on the horizontal surface  72  with a handle assembly  24  spaced from the wafer transfer cassette  22 .  
         [0027]    As shown in FIG. 2B, the handle assembly  24  is then moved in a direction  74  towards the wafer transfer cassette  22  into a preparatory position. The handle assembly  24  is moved by an operator holding onto the grip  50 . Upper surfaces of the engagement formations  56  and  58  are located lower than lower surfaces of the lift formations  42  and  44  so that the engagement formations  56  and  58  move past the lift formations  42  and  44  without the need to lift the wafer transfer cassette  22 .  
         [0028]    As shown in FIG. 2C, the grip  50  is then used to elevate the handle assembly  24  in a direction  76  into a locked position. The lift formations  42  and  44  slide into the slots  64  of the engagement formations  56  and  58 , respectively. The handle assembly  24  is elevated until the lower surfaces  46  contact the base surfaces  66 .  
         [0029]    As shown in FIG. 2D, the operator then further elevates the handle assembly  24  in the direction  76 . The wafer transfer cassette  22  is elevated together with the handle assembly  24  in the direction  76 . The operator can now use the grip  50  to move the transfer cassette  22  into another position.  
         [0030]    [0030]FIG. 3 illustrates an apparatus  80  for handling a wafer which, in addition to the transfer cassette  22  and the handle assembly  24 , further includes a stator  82  and a rotor  84 .  
         [0031]    The stator  82  defines a cavity in which the rotor  84  is mounted. The rotor  84  is mounted to the stator  82  for rotation about an axis  86 .  
         [0032]    The apparatus  80  also includes transfer cassette support rods  90  and wafer support rods  92 . The transfer cassette support rods  90  are positioned so that the wafer transfer cassette  22  is insertable, utilizing the grip  50 , into an enclosure  94  defined in the rotor  84  and the wafer support rods  92  are then located above the wafers  70 . The rail supports  38  are located on lower ones of the support rods  90 A and the wafer transfer cassette  22  is then pushed so that the rail supports  38  slide along the lower support rods  90 A. Side support rods  90 B are located directly adjacent the side walls  26  and  28 . Upper support rods  90 C are located above and directly adjacent upper edges of the sidewalls  26  and  28 . The wafer support rods  92  are located directly above and adjacent the wafers  70 . The rods  90  and  92  are all mounted to the rotor  84  and all extend in a direction of the axis  86 .  
         [0033]    FIGS.  4 A-C further illustrate how the handle assembly  24  is used for locating the wafer transfer cassette  22  inside the rotor  84 . In FIG. 4A, an upper edge  98  of the flange  54  is located below upper edges of the wafers  70 . The flange and the handle assembly  24  are thus insertable in a direction  100  below the wafer support rods  92  without the need for first moving the handle assembly  24  in a downward direction. In fact, an entire upper periphery of the flange  54  is dimensioned to be entirely within a profile projection of the wafers  70  and the transfer cassette  22  so as to be universally used for inserting the transfer cassette  22  and the wafers  70  into enclosures having not only the wafer support rods  92  but also other support rods and components located around the wafers  70  and upper edges of the transfer cassette  22 . Side edges of the flange  54  and the engagement formations  56  and  58  are also located entirely within a projection of the wafer transfer cassette  22  so as to be insertable not only between the side rails  90 B but also in between other components, used in other machines, located next to the sidewalls  26  and  28 .  
         [0034]    Referring now to FIG. 4B, the handle assembly  24  is disengaged from the wafer transfer cassette  22  by moving the handle assembly  24  in a downward direction  102  until lower surfaces of the stands  68  contact the lower rails  98 . A lower periphery of the flange  54  and edges of the stands  68  are entirely located within a profile projection of the wafer transfer cassette  22  when the handle assembly  24  is located in the position shown in FIG. 4B.  
         [0035]    As shown in FIG. 4C, the handle assembly  24  is then moved in a direction  104  away from the wafer transfer cassette  22 . A vertical spacing between a lower edge of one of the stands  68  and an upper surface of the formation  56  is less than a spacing between a lower surface of the rail supports  38  and the lower surface  46  of the lift formation  42 , so as to allow for movement of the handle assembly  24  away from the wafer transfer cassette  22  without the need to lift the wafer transfer cassette  22 .  
         [0036]    The handle assembly can again be engaged and the wafer cassette be removed by following the sequence of FIGS.  4 A-C in a reverse order.  
         [0037]    It can thus be seen that the handle assembly  24  can be engaged with the wafer transfer cassette  22  without the need for lifting the wafer transfer cassette  22 . The handle assembly  24  can also be used for inserting both the wafer transfer cassette  22  and the handle  24  between the rods  90  and  92 . The handle assembly  24  can also be disengaged from the wafer transfer cassette  22  without the need for moving the wafer transfer cassette  22  out of its position shown in FIG. 4A.  
         [0038]    [0038]FIG. 5 illustrates an apparatus  120  for wafer transportation, according to another embodiment of the invention. The apparatus  120  is similar to the apparatus  20  shown in FIG. 1 except for the manner in which the lift formations  142  and  144  and engagement formations  156  and  158  are formed. The lift formations  142  and  144  extend away from side edges of sidewalls  26  and  28 . The engagement formations  156  and  158  are slightly bent out of a plane in which a flange  154  is located. The engagement formations  156  and  158  are engageable with the lift formations  142  and  144 , and then disengageable therefrom, in a manner similar as hereinbefore described with reference to FIGS. 2 and 4.  
         [0039]    While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative and not restrictive of the current invention, and that this invention is not restricted to the specific constructions and arrangements shown and described since modifications may occur to those ordinarily skilled in the art.