Abstract:
The invention relates to a device for catching a plurality of slices to be detached from a holding element, having a frame, a holder, attached to the frame, for accommodating the holding element holding the slices, at least two guiding elements on the sides and at least one bottom catching element, the guiding elements on the sides each being arranged on the frame in pairs on the right and the left.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a device for gently catching thin slices, especially wafers from semiconductor material, especially silicon. 
     During the manufacture of wafers, silicon blocks are glued to a holding element. Thereafter, the silicon block is sawn into individual thin slices, which still adhere to the holding element after the sawing process. For further processing the slices are detached from the holding element. As the thin slices are extremely delicate, it is absolutely necessary to gently and safely store them during and after the detaching from the holding element. 
     SUMMARY OF THE INVENTION 
     The invention is based on the object of creating a device with which wafers can be caught in an easy, gentle and secure way. 
     Said object is achieved by a device for catching a plurality of slices to be detached from a holding element, comprising a frame, a holder, attached to the frame, for accommodating the holding element holding the slices, at least two guiding elements on the sides and at least one bottom catching element, the guiding elements on the sides each being arranged on the frame in pairs on the right and the left. The core of the invention consists in connecting the holding element with the silicon slices in a frame and keeping the silicon slices stable during and after the detaching from the holding element through rollers arranged on the sides and below the silicon slices. This way, damage to the silicon slices is avoided. 
     Additional features and details of the invention result from the description of an embodiment based on the drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  shows a catching device for silicon slices; 
         FIG. 2  shows a side view of the catching device according to  FIG. 1 , with the silicon slices being attached to a holding element; and 
         FIG. 3  shows a side view according to  FIG. 2 , with the silicon slices being detached from the holding element. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following, the configuration of an embodiment of a catching device  4  will first be described in more detail with reference to  FIGS. 1 to 3 . The catching device  4  essentially exhibits the shape of a cube in a lattice shape. The front sides are formed by a fore and a rear U-shaped front part  13 ,  14 , each consisting of a base strut  15  running in a cross direction and a left and a right leg  16 ,  17  each extending upwardly therefrom. The front parts  13 ,  14 , which face one another, are each connected with each other near the top and bottom ends of the legs  16 ,  17  by an upper longitudinal carrier  18  and a lower longitudinal carrier  19  running in a longitudinal direction, so that there emerges a rigid, essentially cubic trestle. In the area of the base struts  15  of both the fore front part  13  and the rear front part  14  there are arranged two swingable arms  20 ,  21  between which there are arranged rotatably mounted rollers  22 ,  23 . The rollers  22 ,  23  form a bottom catching element. The arms  20 ,  21  are lockable in the upwardly swung position shown in  FIG. 1 . Between the two left legs  16  on the one side, and the two right legs  17  on the other side, there are arranged in each case above one another on the left side and on the right side, respectively, guiding elements on the sides in the form of rollers  24  and  25 , and  26  and  27 , respectively, which are carried by corresponding arms  28  and  29 , and  30  and  31 , respectively, which are swingably attached to the legs  16  and  17 , respectively. Along the swing axes of the arms  28  to  31 , the left and the right legs  16  and  17  are connected to one another by means of swing rods  38 . On one of said swing rods  38 , there may be arranged, displaceably mounted, a fore and a rear end safety device  39  and  40 . The end safety devices  39 ,  40  serve to protect the slices  3  against falling over and to prevent them from falling out of the catching device  4 . To this end, the end safety devices  39 ,  40  shown in  FIGS. 1 to 3  point, in the form of pointers, towards the inside of the cube. The arm  28  is attached to the front parts  13 ,  14  at the same height as the arm  30 . Likewise, the arm  29  is attached to the front parts  13 ,  14  at the same height as the arm  31 . The upper rollers  24  and  26 , and the lower rollers  25  and  27 , respectively, are adjustable towards one another, thereby making the catching device  4  adaptable to the width of the slices  3 . All rollers  22  to  27  are provided, on their surface, with a plastic or rubber hose  32 , which exhibits circumferential grooves in a large number. The grooves are sized such that there can be held in each groove exactly one slice  3  in an essentially vertical position in a tilt-safe manner. The grooves exhibit, for example, a rectangle profile or a triangle profile with a profile height of 0.1 to 10 mm, especially 0.5 to 5 mm, especially 1 to 3 mm. 
     At the top end of the left and right legs  16  and  17  there are exchangably articulated in each case left and right carrier arms  33  und  34 . The carrier arms  33  and  34 , which face one another in the longitudinal direction, are connected by rods  35 . Between the carrier arms  33 ,  34 , which face one another in a cross direction and which are swung into the horizontal, and between the rods  35 , respectively, there remains an accommodating gap  36  to accommodate the holding element  1 . Together with the rods  35 , the carrier arms  33 ,  34  form a holder  41 , which is tuned to the dimensions of the holding element  1 . At the tops ends of the left and right legs  16  and  17  there are also attached in each case transportation holders  37 . 
     Apart from the end safety devices  39 ,  40 , the catching device  4  is, both in the longitudinal and in the cross direction, essentially mirror-symmetrical to a vertically running central longitudinal and central cross plane, respectively. 
     In the following, the function of the catching device  4  will be described. For the manufacture of wafers, blocks of a raw material are first sawn into columns, which, in their cross-section, almost have the shape of the wafers to be manufactured. Generally they can be blocks of any material, especially of any semiconducting material, preferably of silicon. The wafers are especially envisaged for use in photovoltaics. The columns exhibit a dimension (length×width×height) of e.g. 500×100×100 mm up to 900×400×400 mm. On a longitudinal surface, the columns are glued, via a glue layer  2 , to a holding element  1  consisting, for example, of glass. Thereafter, the columns are sawn by a commercially available wire saw into slices  3 . The slices  3  exhibit a thickness of 100 μm to 400 μm. In accordance with the aforementioned cross-section of the columns, the slices  3  have a surface of 100 mm×100 mm to 400 mm×400 mm. 
     After the end of the sawing process, the holding element  1 , together with the slices  3  attached thereto, is inserted into the catching device  4  as shown in  FIG. 1 . The catching device  4  serves the gentle stabilisation of the slices  3  for as long as they are attached to the holding element  1 , and the guiding, catching and holding of the slices  3  after they have been removed from the holding element  1 . 
     Before the slices  3  are detached from the holding element  1 , they can e.g. run through a sequence of cleaning steps or other processing processes. The detaching takes place in a process basin, which is filled with a degluing solution. Up to this point in time, the slices  3 , via the glue layer  2 , are firmly connected to holding element  1 . In order to facilitate the dismantling process, the wire-sawn columns introduced into the catching device  4  can be tilted along their longitudinal axis by an angle of between 0° and 45° against the horizontal. The end of the dismantling process is characterised by the complete detaching of all slices  3  from the holding element  1 . After the detaching of the slices  3  from the holding element  1 , they are caught in the catching device  4 . The slices  3  are safely held in the catching device  4  and, whilst in the catching device  4 , can run through further process steps. Finally, the slices  3  in the catching device  4  are transferred into a liquid-filled unloading wagon, with which the slices  3  are conveyed to a singling device. At the end of the process there emerge cleaned, high-quality, singularised wafers made of a semiconductor material, especially silicon. The advantage of the invention is that the catching device  4  holds the individual slices  3  at all times in a gentle and safe manner, that it enables good access to each individual slice from both sides for possible cleaning or other processing processes and, finally, that is protects the slices  3  against damage.