Patent Publication Number: US-2012039690-A1

Title: Devices and methods for processing and handling process goods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of copending International Application No. PCT/EP2009/005288, filed Jul. 21, 2009, which is incorporated herein by reference in its entirety, and additionally claims priority from German Application No. 102008034505.9, filed Jul. 24, 2008, which is also incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to devices and methods for processing and handling process goods and, in particular, to devices and methods suitable for handling plate-shaped process goods, such as, for example, semiconductor wafers, as are applied when manufacturing solar cells. 
     Semiconductor wafers and, exemplarily, poly-crystalline or mono-crystalline semiconductor wafers of small thicknesses in a range between 0.1 mm and 0.5 mm, such as, for example, 0.2 mm, are, when manufacturing solar cells, subjected to different process steps which, among others, include an etching process, a cleaning process and a drying process. In so-called batch systems, a number of wafers or substrates in a carrier are transported from one bath to the next by a gripper for performing such methods. 
     Methods for transporting semiconductor wafers through different wet regions are known, in which the wafers are placed on successive rolls such that a wafer will rest on at least two rolls. These rolls are each driven individually via main shafts and bevel gears, spur gears and endless means or the like. The rolls may comprise O-rings or cylinders as resting points for the wafers. These cylinders may be made of an absorbent material wetting the wafer with a medium. The wafers here are either transported horizontally or else the rolls form a path on which the wafers are lowered into the media regions and lifted again. Stop strips or washer disks are provided at the rolls in order to keep the wafers in their paths. With a horizontal transport, the medium flows over the wafers coming in and going out via a narrow slot, thereby ensuring a higher medium level. In order to prevent the wafers from floating, hold-down systems are employed. These in turn may again be rolls or cylinders which are driven separately or not. Such systems are principally employed by the Schmid Technology Systems GmbH and Rena GmbH companies, for example. 
     An alternative feeding system for wafers on endless means has already been employed by the applicant, in which a handling system puts a carrier provided with wafers on a feed chain which transports the basket through a basin. At the end of the basin, the basket is picked up again by a handling system. 
     There is demand for devices and methods for processing process goods which allow process goods to be handled so as to treat the materials with care. 
     SUMMARY 
     According to an embodiment, a device for processing a process good with a process medium may have: means for providing the process medium; and transport means having a transport element configured to move the process good along a process path between being accepted by a delivery device and being delivered to an accepting device so as to move with the process good from being accepted to being delivered, wherein the device is configured such that the process good enters the process medium laterally and is moved through same or passed by same while floating on the process medium, wherein the means for providing the process medium has: a process medium reservoir covered by a plate, the plate having a top surface, and the plate being perforated by a plurality of openings, and means for filling the process medium reservoir such that the process medium reservoir overflows and thereby the process medium is driven through the openings onto the top surface. 
     According to another embodiment, a system for processing a process good with a process medium may have: a processing device having a device for processing a process good with a process medium as mentioned above; and at least either a delivery device configured to feed the process good for being accepted by the processing device; or an accepting device configured to accept the process good from the processing device. 
     According to another embodiment, a method for processing a process good with a process medium may have the steps of: accepting the process good by a processing device from a delivery device; providing the process medium by means of a process medium reservoir covered by a plate, the plate having a top surface, and the plate being perforated by a plurality of openings, wherein the process medium reservoir is filled such that it overflows and thereby the process medium is driven through the openings onto the top surface; by a transport element of a driving device of the processing device, which moves along the process path with the process good from accepting the process good to delivering the process good, moving the process good along the process path, the process good entering the process medium laterally and being moved through same or being passed by same while floating on the process medium; and delivering the process good to an accepting device after having passed the process path. 
     According to still another embodiment, a device for handling a process good may have: a delivery device having first endless means which has a transport element for transporting the process good to a delivery region in which the endless means travels around an axis at a first radius; an accepting device having second endless means for accepting the process good in the delivery region and for transporting the process good from the delivery region, the second endless means traveling around the same axis at a second radius such that the second endless means moves faster than the first endless means, wherein the ratio between the first and second radii is such that the second endless means moves the process good from a track of travel of the transport element around the axis at such a speed that the process good does not interfere in the movement of the transport element around the axis. 
     Embodiments of the invention are based on the finding that it is possible to expose a process good to a process medium and, in particular, a process liquid in a particularly careful manner by the process good entering the process medium laterally and being moved through same or passed by same while floating on the process medium. This allows reducing strain in particular in a plate-shaped process good of small thickness, such as, for example, poly-crystalline or mono-crystalline semiconductor wafers having a thickness between 0.1 mm and 0.5 mm, when processing same with a process medium and, in particular, a process liquid. This allows reducing breaking of the process good and, consequently, rejects. Embodiments of the invention may particularly be adapted for processing and handling poly-crystalline or mono-crystalline silicon wafers of a thickness in the range of 0.2 mm. 
     Embodiments of the present invention relate to devices and methods for processing and handling solar cell wafers which may be semiconductor wafers of the type described above. 
     In embodiments of the present invention, the process medium is a process liquid and, in particular, an etching liquid or a cleaning liquid. In alternative embodiments of the invention, the process medium may be a liquid containing components which cause the process good to be coated when contacting the process good by the process medium, due to a chemical reaction. 
     Embodiments of the invention relate to devices and methods in which the process good, such as, for example, a wafer or a substrate, is transported separately and individually. In embodiments, the invention relates to devices and methods in which the transport means is configured to transport wafers or substrates through a system separately one after the other in one or several rows. 
     Due to the fact that, in embodiments of the invention, the process good enters the process medium laterally, the movement of the process good, caused by the transport element, along the process path through the processing device may be a movement purely horizontal relative to the earth&#39;s gravitational field. This allows material to be transported in a careful manner. 
     In order to implement the process good entering the process medium laterally, embodiments of the invention include a process medium reservoir filled with a process medium such that a process medium projection or supernatant or liquid projection or supernatant forms above an upper boundary of the process medium reservoir above which the process good is fed. Lateral walls may be provided so as to support the formation of such a liquid projection. In alternative embodiments, the process good may enter the process medium laterally via lateral openings in a process medium reservoir. Alternatively, the means for providing the process medium may comprise an opening plate and/or a plurality of nozzles for feeding the process medium from above the process path such that the process good enters the process medium provided by the opening plate or the plurality of nozzles laterally. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will be detailed subsequently referring to the appended drawings. Same elements or elements of the same effect are, where applicable, provided with the same reference numerals in the drawings, in which: 
         FIGS. 1   a  and  1   b  show embodiments of a processing device including a hold-down function schematically; 
         FIG. 2  shows an embodiment of a processing device including rest regions for a process good schematically; 
         FIGS. 3   a  and  3   b  show alternative embodiments of a processing device schematically; 
         FIGS. 4   a ,  4   b ,  5 ,  6   a ,  6   b , and  7  show variations of embodiments of processing devices schematically; 
         FIGS. 8   a  to  8   d  show a perspective view, a side view, a top view and a front view, respectively, of an embodiment of a processing device schematically; 
         FIGS. 9   a  to  9   e  show representations for illustrating operation of a device for handling a process good schematically; 
         FIGS. 10   a  to  10   d  show a perspective view, a side view, a top view and a front view, respectively, of an embodiment of a processing device; 
         FIGS. 11   a  to  11   c  show schematic illustrations of an alternative embodiment of a processing device; and 
         FIGS. 12   a  and  12   b  show a schematic isometric illustration and a schematic side view of an embodiment of an accepting/delivery device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will subsequently be described in particular using devices and methods for processing process goods in the form of poly-crystalline or mono-crystalline semiconductor wafers. However, it is obvious that embodiments of the invention may also be configured for processing or handling different process goods, such as, for example, glass panels or other plate-shaped process goods. 
       FIG. 1   a  shows a processing device for a process good  10  which may exemplarily be a semiconductor wafer of an essentially square shape having a thickness of 0.2 mm and an edge length of usually up to 156 mm, as is applied when manufacturing solar cells, which, however, is by no means limiting, schematically. 
     The processing device includes means  12   a  for providing a process medium and, in particular, a process liquid which a process medium reservoir  12   a  comprises. Filling means  12   c  for filling the process medium reservoir with the process medium is also provided. The filling means  12   c  is configured to cause overflow of the process medium reservoir  12   a  such that a process medium projection  14  is produced above an upper boundary  12   b  of the process medium reservoir  12   a.    
     It is to be mentioned here that, in embodiments of the invention, the upper boundary  12   b  of the process medium reservoir may exemplarily be formed by a hole plate comprising a plurality of holes through which the process medium reaches the top surface thereof so as to form a process medium film there. Lateral boundaries may be provided so as to prevent lateral overflow of the process medium such that same only flows over the front and back edges of the process medium reservoir  12   a.    
     Transporting means is provided for moving the process good  10  in a direction B along a process path. The transport means  16  includes endless means  18  which may be rotated about two axes  20  and  22  or about rolls or discs resting on the axes. Transport elements  24 , some of which are schematically shown in  FIG. 1   a  and provided with the reference numeral  24 , are attached to the endless means. Additionally, hold-down elements  26  are attached to the endless means. A motor (not shown) for driving the endless device  18  so as to move, as is shown in the Figures, in a counter-clockwise direction is provided. 
     In operation, the medium reservoir  12   a  is supplied with the process medium, as is indicated in the Figures by respective arrows, using the filling means  12   c  which may exemplarily be implemented by a pump and corresponding fluid interconnects such that the process medium projection  14  above the upper boundary  12   b  of the process medium reservoir  12   a  is produced. The process medium or process liquid here may flow over at the, in the direction of movement B, front and back ends of the medium reservoir  12   a  as is indicated in the Figures by respective arrows  28 . Lateral boundaries may be provided so as to prevent lateral overflow. 
     The motor (not shown) drives the transport means  16  such that the endless means  18  rotates in a counter-clockwise direction. The transport elements  24  here are rotated about the axis  20  and accept the process good  10  from a delivery device (not shown in  FIG. 1   a ) at the left-hand end of the transport means, by a transport element  24  engaging the back end of the process good  10 . With an ongoing movement in the direction of movement B, the transport element  24  acts as a pusher element for the process good  10  and moves through the processing device along the process path together with the process good. In the region of the axis  22 , the transport element  24  finally loses contact with the process good  10  when moving around the axis  22  to the top together with the endless means  18 . 
     As can be seen in  FIG. 1   a,  the transport means  16  and the means for providing the process medium  12  are arranged such that the process good  10  is passed by same while floating on the process medium  14 . The process good is positioned by the hold-down elements  26  which may be implemented as pins. A flow caused by the filling of the process medium reservoir  12   a  from the bottom to the top here may have a buoyant effect on the process good. 
     In the embodiment shown in  FIG. 1   a,  it is possible to process only the bottom side of the process good  10  with the process medium. 
     In the example shown in  FIG. 1   a,  the process good is thus transported on the process medium level. Alternatively, it is possible to transport the process good below the process medium level by arranging the transport means  18  and the means for providing the process medium such that the hold-down elements hold the process good immersed into the process medium. An embodiment where such a procedure is implemented is shown in  FIG. 1   b.    
     The means  12  for providing a process medium  14 , shown in  FIG. 1   b,  may basically correspond to the means shown in  FIG. 1   a.  Additionally, the transport means  16  may also correspond to the transport means shown in  FIG. 1   a,  wherein only the transport means  16  is arranged relative to the means  12  such that the process good  10  is held below the medium level of a medium projection formed by the upper boundary  12   b,  by transport elements  30 . In the embodiment shown in  FIG. 1   b,  the transport elements are made to be T-shaped such that they are effective as both hold-down elements and pusher elements. 
     The mode of functioning of the processing device shown in  FIG. 1   b  basically corresponds to the mode of functioning described above making reference to  FIG. 1   a,  with the exception that the transport means  16  causes the process good  10  to enter the process medium  14  laterally at the position of the arrow E. 
     It is to be explained here that the transport means  16  are configured such that the movement of the process good  10 , caused by the transport elements  24  and  30 , along the process path is a movement purely horizontal relative to the earth&#39;s gravitational field, wherein the process medium may cause slight floating up and down of the process good, but only in a very limited range of exemplarily less than 5 mm or less than 1 mm. 
     In  FIGS. 1   a  and  1   b,  only exemplarily, some transport elements and hold-down elements  24 ,  26  and transport elements  30  are illustrated. It is to be pointed out here that the endless means  18  may comprise corresponding elements in a distributed manner along the entire length thereof so that process good  10 , such as, for example, in the form of semiconductor wafers or semiconductor substrates, may be moved along the process path separately one after the other. Thus, a transport element  24  or  30  may be effective as both a pusher for an upstream process good and as a stopper for a downstream process good. 
     Additionally, it is pointed out that the embodiment shown in  FIG. 1   a  may comprise T-shaped transport elements and the embodiment shown in  FIG. 1   b  may comprise transport elements and hold-down elements as are shown in  FIG. 1   a.    
     In embodiments of the invention, the process good may be transported while floating on a process medium pad. Thus, the process good may exemplarily be accepted by delivering means or be delivered to an accepting means in which the process good also floats or rests on a medium pad or a gas pad. In a system comprising several sections, the process good may, depending on the section, float on a medium film which exemplarily flows in from below via distributor plates, or glide on a gas pad, such as, for example, air, N 2 , etc. The transport means may, as is described, comprise endless means, such as, for example, a chain, a belt and the like, where corresponding transport elements, such as pushers and hold-down elements, are attached. Alternatively, a carriage may be provided to which corresponding hold-down elements and pushers are attached and which moves the process good along the process path. In embodiments, the endless means may comprise two endless means spaced apart from each other in a direction transverse to the transport direction, where respective transport elements are attached. In addition, lateral guides may be attached to the transport means so that movement of the process good perpendicular to the direction of movement B can be limited. Thus, the process good can be guided in the horizontal plane and be limited in the Z axis (hold-down function). 
     Embodiments in which the process good floats on a medium film allow little mechanical strain on the process good, single-side treatment of the surfaces, good medium exchange on the process good surface, fast temperature dissipation in exothermal reactions and quick removal of gases forming on the surface of the process good. 
     An alternative embodiment in which the process good rests on a transport system is shown in  FIG. 2 . 
     In these embodiments, the setup of the means for providing a process medium  12  may basically correspond to the setup described referring to  FIGS. 1   a  and  1   b.  However, in the embodiment shown in  FIG. 2 , a transport means  36  is provided which comprises endless means  38  where rest elements  40  for the process good  10  are attached. Again, only schematically, some rest elements are shown in  FIG. 2 , wherein rest elements may be distributed over the entire length of the endless means  38 . The endless means  38  in turn may be rotated around axes  20  and  22 . The rest elements  40  may be configured to provide for guidance of the process good  10  in both the direction of movement B and in a direction perpendicular to the direction of movement. Again, two endless means spaced apart from each other in a direction transverse to the direction of movement, each comprising respective rest elements, may be provided. 
     As is shown in  FIG. 2 , the process good  10  is guided by the rest elements  40  such that it floats on the process medium projection  14  above the upper boundary  12   b.  In this embodiment where the process good  10  rests horizontally on the rest elements  40  such that it floats on the process medium, i.e. such that the top surface of the process good  10  is above the process medium level, single-side treatment of the process good is possible. 
     In embodiments of the invention, additionally means may be provided which supplies a liquid from above so as to wet the process good to reduce mechanical strain of the process good. In addition, means may be provided which supplies liquid from above so as to hold the process good down. 
     It is to be pointed out here that for reasons of illustration in particular vertical dimensions are illustrated in the Figures in an exaggerated manner. It is particularly to be kept in mind that embodiments of the invention are in particular suitable for processing or handling plate-shaped process goods of a thickness in the range of 0.2 mm. 
     It is additionally pointed out that, in all the embodiments of the invention, means for feeding process medium from above, such as, for example, distributor plates or spray nozzles, may be provided in addition or as an alternative to the means causing process medium to be supplied from below. 
     It need not be explained separately that the elements  40  in operation again accept a process good from a delivery device at the left end of the transport means and deliver the process good to an accepting device at the right end of the transport means, wherein the elements  40  move together with the process good from acceptance to delivery. The movement of the process good, caused by the rest elements  40 , along the process path again is a purely horizontal movement relative to the earth&#39;s gravitational field. 
     The embodiment described referring to  FIG. 2  also allows material to be transported carefully. In addition, a setup as has been described referring to  FIG. 2  allows automatic removal of broken process goods so that this does not cause any additional silicates to form in the medium, which may result in an increased useful life of media. 
     An alternative embodiment of a processing device is shown in  FIGS. 3   a  and  3   b . In this embodiment, transport means includes endless means  48  which may be rotated around two axes  20  and  22 . Transport elements in the form of holders  50  on which the process good  10  may be placed in an inclined position, i.e. at an angle α to the horizontal line  52 , are attached to the endless means  48 . The holders  50  may be formed by longer lower pins and shorter upper pins which protrude from the endless means  48 , the process good resting on the lower pins. 
     Means  54  is provided for providing a process medium which supplies process medium from above so as to wet at least the surface of the process good directed to the top with the process medium. The means  54  gives rise to, at least along a portion of the process path over which the transport means moves the process good, a volume into which process medium is sprayed or introduced, wherein the process good enters this volume and, thus, the process medium laterally. In addition, the holders  50  move together with the process good along the process path. 
     The embodiment shown in  FIGS. 3   a  and  3   b  allows a space-saving setup, process good overflow from above, thereby allowing good heat removal in exothermal process and good rinsing. In addition, the setup of the transport means may be more independent of the process good format. 
     In embodiments, the invention may be configured to process and handle plate-shaped process goods comprising two opposite main surfaces, the device being implemented such that the main surfaces when being moved along the process path are arranged so as to be horizontal or at an angle relative to the horizontal line. 
     Generally, the means for providing a process medium may be formed in any manner possible as long as the transport means is able to cause the process good to enter the process medium laterally and be moved through it or be passed by same while floating on the process medium. In embodiments of the invention, the process medium providing means comprises a process medium container covered by a distributor plate. The distributor plate includes a plurality of fluid conduits through which the process medium or process liquid reaches the top face of the distributor plate when the process medium container is filled so as to overflow. This causes liquid to be pushed through the fluid conduits and a liquid projection to form on the distributor plate into which the process good may enter laterally or which the process good may be passed by while floating. Caused by the liquid flow through the fluid conduits from the bottom to the top, a buoyant force may act on the process good, which may cause the process good to float on the liquid projection which may be formed by a liquid film. Lateral boundary walls may be provided so as to prevent the process medium from flowing off laterally from the top surface of the distributor plate. In embodiments of the invention, the process medium thus only flows over on the sides which the process good passes. Alternatively, the process medium may be provided from above by a distributor plate or spray nozzles, wherein in this case the process good enters the process medium volume produced by this laterally. 
     Different implementations of the means for providing the process medium are shown in  FIGS. 4   a  to  7 . In these Figures, a respective transport element is referred to schematically by the reference numeral  60  and a direction of movement of the process good is referred to by B. 
     In accordance with  FIGS. 4   a  and  4   b , the process medium  14  is fed to the process medium reservoir  12   a  by corresponding filling means  12   b,  as is indicated by respective arrows directed to the top. In accordance with  FIG. 4   a , the process good  10  is transported while floating on the process medium level  14   a,  whereas in accordance with  FIG. 4   b  the process good  10  is transported below the process medium level  14   a.    
     In the embodiment shown in  FIG. 5 , the process medium  14  is fed into the process medium reservoir  12   a  using process medium providing means  62  arranged above the process path such that same flows over at the, in the direction of movement B, front and back ends, see arrows  28 . The process medium providing means  62  may exemplarily be implemented by a distributor plate or by spray nozzles. Thus, the medium level  14   a  is above the process good  10 . When feeding from above, which is schematically indicated by the arrows directed downwards in  FIG. 5 , it is possible to omit hold-down elements, since the process good can be held down by the process medium flow from above. Thus, shadowing on the surface of the process good can be avoided completely. Additionally, in the embodiment shown in  FIG. 5 , the process medium may also be fed from below. 
       FIGS. 6   a  and  6   b  show an alternative embodiment including a closed medium reservoir  64  which comprises an inlet opening  66  in a, in the direction of movement B, back wall and an outlet opening  68  in a, in the direction of movement, front wall, schematically. The inlet opening  66  and the outlet opening  68  allow the process good  10  and the transport element  60  to move through the medium reservoir. Filling the medium reservoir which results in an overflow  70  through the inlet opening  66  and the outlet opening  68  may be done by filling means  64   a  from below ( FIG. 6   a ) or by filling means  64   b  from above ( FIG. 6   b ). 
     In embodiments, a wet process chamber which represents a device for providing a process medium may be implemented to be an overflow tank, the surface of the process good being positioned below the liquid level. The process good may enter through a slot into the tank the cross-section of which is small enough so as to only let through part of the liquid volume circulating. The orientation of the flow direction in the inner tank can provide for the process good to be kept below the liquid, exemplarily by a flooding tank from above. 
       FIG. 7  finally shows an embodiment in which process medium providing means  72  is provided above the process path along which the process good  10  is moved in the direction of movement B. A process medium reservoir  74  as an accepting container is provided below the process path. The process medium providing means  72  may be implemented to be a distributor plate or a nozzle plate and is configured to emit the process medium downwards such that a process medium volume which is indicated in  FIG. 7  by the arrows bearing the reference numeral  76  is produced. The process good  10  enters this process medium volume  76  laterally when moving in the direction of the arrow B. Instead of the horizontal position shown in  FIG. 7 , in this embodiment, the process good may also be positioned to be inclined, as has been discussed above referring to  FIGS. 3   a  and  3   b . In the embodiment shown in  FIG. 7 , the process good is positioned in the medium reservoir  74  above the medium level. High flow-through, heat dissipation in exothermal reactions and good rinsing can be achieved here. 
     There is no need for explaining in detail that means for feeding overflowing process medium back to the respective filling means may be provided in embodiments of the invention. Equally, in the embodiment shown in  FIG. 7 , means may be provided for feeding back process medium from the process medium reservoir  74  to the means  72 . Additionally, means may be suitably provided for treating the process medium again before it is returned. 
     An embodiment of an inventive processing device which generally operates following the principle shown in  FIG. 2   a  will be discussed subsequently referring to  FIGS. 8   a  to  8   d.    
       FIG. 8   a  shows a perspective view of a system comprising an inventive processing device  100 , a delivery device  102  and an accepting device  104 . Additionally, a processing stage  106  upstream of the delivery device  102  and a processing stage  108  downstream of the delivery device  104  are shown schematically.  FIG. 8   b  shows a schematic side view of the processing device  100 , and  FIG. 8   c  shows a schematic top view thereof, however without wetting means  110  which is arranged above the process path.  FIG. 8   d  finally shows a schematic sectional view along the line D-D in  FIG. 8   b . It is to be mentioned here that the Figures all show those feature considered to be needed for describing the invention, wherein, however, not all of the features are illustrated in the respective views so as not to overload same. 
     The processing device  100  includes transport means having two endless belts  120  which are movable via rolls  122  and  124  positioned on axes. Rest elements for a process good  10  exemplarily in the form of a poly-crystalline or mono-crystalline semiconductor wafer are attached to the endless belts  120 . Four respective rest elements  126  receive one semiconductor wafer  10 . As can be seen best in  FIG. 8   c , rest elements  126  are distributed over the endless belts  120  such that semiconductor wafers  10  may be transported individually one after the other. The rest elements  126  may be configured to guide the semiconductor wafer both in the direction of movement B and transverse to the direction of movement. For this purpose, the rest elements may comprise lateral projecting regions  128  which determine the position of the wafer  10  transverse to the direction of movement. In addition, the rest elements  126  comprise a higher central region  130  which forms a front and back stop for a respective wafer. In order to allow careful handling of the wafer and keep shadowing regions as small as possible, the rest area on which the wafer  10  rests may be beveled. 
     A suitable drive motor (not shown) may be provided to drive one of the axes on which the rolls  122  and  124  are arranged so as to drive the endless belts  120  and, thus, the rest elements  126 . 
     Additionally, the processing device includes means for providing the process medium. In the embodiment illustrated, this means includes the wetting means  110  already mentioned which is arranged above a process path along which the wafers  10  are moved. The process medium providing means additionally includes a process medium container  132  ( FIG. 8   d ) covered by a perforated plate  134 . Openings  136  through which process medium may pass from the process medium reservoir  132  to the top of the perforated plate  134 , may be provided in the perforated plate  134 . Means  138  for filling the medium reservoir  132 , such that process medium passes through the openings  136  to the top of the perforated plate  134  so as to reach a process medium projection  140  as is shown in  FIG. 8   d , is illustrated schematically in  FIG. 8   d.    
     As can be gathered from  FIG. 8   d , lateral overflow of the process medium projection  140  is avoided by lateral walls  142  and  144 . The process medium only flows over at the, in the direction of movement B, front and back ends of the perforated plate  134 , i.e. of the medium reservoir  132 , as is shown in  FIG. 8   b  by corresponding arrows  128 . The overflowing medium may be collected in a collecting container  146  and be used again for filling the process medium reservoir by suitable feedback means (not shown) using the filling means  138 . The filling means  138  may exemplarily comprise a plurality of fluid lines which lead into the process medium reservoir  132  and through which the process medium can be introduced into the process medium reservoir  132  by means of corresponding pump means. 
     In operation, the process medium reservoir  132  is filled with the process medium, such as, for example, an etch solution for a semiconductor wafer, such that a process medium projection is produced on the top surface of the perforated plate  134 . A wafer is moved through this liquid projection using the transport means, in particular the rest elements  126 , the wafer  10  entering the process medium projection  140  from the left-hand side. The movement of the wafer, caused by the transport means and, in particular, the endless belt  120  and the rest elements  126 , along the process path through the process medium projection  140  is a movement purely horizontal relative to the earth&#39;s gravitational field. Thus, the wafer can be processed by the process medium in a manner that handles the material with care. 
     In the embodiment illustrated in  FIGS. 8   a  to  8   d , as a supportive measure, a process medium is provided from the top by the wetting means  110  which may comprise spray nozzles through which the process medium is fed from above, as is indicated in  FIG. 8   b  by the arrows  150 . This wetting allows destroying the surface tension of the medium and floating can be prevented so that no hold-down systems are necessary and there is no shadowing on the surface of the process good. As can be gathered from  FIG. 8   d , the endless belts in the embodiment shown travel to recesses  152  in the top of the perforated plate  134 , thereby causing the process good  10 , such as, for example, the semiconductor wafer, to be transported closer to the top surface of the perforated plate  134 . 
     In embodiments of the invention, the process good, such as, for example, the wafers or substrates, may thus be placed on a transport device, such as, for example, a chain or belt system with a positioning system for the wafers attached thereto. The transport speed may basically be the same at every position throughout a system comprising several stages, wherein the level of the wafer may also be nearly equal in the entire system. Zones between different operating stages, for example between etching and cleaning or drying, may be realized by a roll or O-ring system. 
     In embodiments of the invention, cleaning or etching of the process good may be performed in the processing device, depending on which process medium is provided. Further processes may be performed in upstream or downstream operating stages, as is shown schematically in  FIG. 8   a  at  106  and  108 . An intermediate transport system which will be discussed in greater detail below referring to  FIGS. 9   a  to  9   e  may be used for bridging between different processing stages in a system in embodiments of the invention. 
       FIG. 9   a  shows a first processing device  202 , a second processing device  204  and an accepting/delivery device  206 . The processing devices  202  includes an endless belt  220 , the accepting/delivery device  206  comprises an endless belt  222  and the processing device  204  comprises an endless belt  224 . Exemplarily, the devices  202 ,  204  and  206  shown in  FIG. 9   a  may be implemented by the processing device  100 , the accepting device  104  and the downstream processing stage  108  shown in  FIG. 8   a.    
     The endless belt  220  travels over rolls  226  and  228  at a radius r 1 . The endless belt  222  travels over rolls  230  and  232  at a radius r 2 . The endless belt  224  travels over rolls  234  and  236  at a radius r 1 . The rolls  228  and  230  are positioned on a same axis  238  and the rolls  232  and  234  are positioned on a same axis  240 . One of the axes may be driven by a motor (not shown) so as to move all the endless belts  220 ,  222  and  224  at the same time. 
     The processing devices  202  and  204  may comprise corresponding rests  242  for transporting a process good  10  through a process path. As an alternative to the form shown, the rests may of course also be of a different form. The endless belt  222  has no rest elements and is made of a material cooperating in terms of friction with the process good so as to allow same to be taken along. Exemplarily, the endless belt  222  may be formed by a round belt made of a suitable material, such as, for example, a polymer. 
     The radius r 2  is greater than the radius r 1 , so that, in correspondence with the gear ratio caused by this, the endless belt  222  rotates faster than the endless belt  220  and the endless belt  224 . 
     The ratio of the two radii relative to each other is set such that the endless means  22  will move the process good from a track of travel of the transport element around the axis  238  or the roll  228  at such a speed that the process good does not interfere in the movement of the successive rest element  242  around the axis  238 . A respective delivery of the process good, which may again be a poly-crystalline or mono-crystalline semiconductor wafer, is shown in  FIGS. 9   b  to  9   e . In accordance with  FIG. 9   b , the process good is in frictional engagement with the endless belt  222  which, as can be recognized in  FIG. 9 , moves the process good  10  away faster than the rest element which here is referred to by the reference numeral  242 , follows. In accordance with  FIG. 9   c , the process good  10  is already outside the track of travel of the rest element  242  around the roll  228  such that this element, when moving around the roll  228 , can no longer meet the wafer  10 . 
       FIGS. 9   d  and  9   e  show the situation when delivering the wafer from the accepting/delivery device  206  to the following processing device  204 . As has been explained above, the endless belt  222  moves faster than the endless belt  224 . This means that the process good catches up with the rest element referred to here by the reference numeral  242  and abuts on the central elevation thereof. After abutting, the process good  10  can no longer move at the speed of the endless belt  222 , but only at the speed of the endless belt  224 . Since the wafer  10  is only in frictional engagement with the endless belt  222 , slipping between same may take place. Delivery from the accepting/delivery device  206  to the processing device  204  is finished when the back rest element that is referred to by the reference numeral  243  in  FIG. 9   e  has finished its circular movement about the roll  234  ( FIG. 9   a ) and is engaged with the process good  10 . This situation is illustrated in  FIG. 9   e.    
     Embodiments of the present invention thus include an accepting device (accepting/delivery device  206 ) which allows a higher speed of the process god transported than the previous processing device. This is, in accordance with the invention, realized in a particularly easy manner by the fact that the endless means of the delivery device and the accepting device travel around the same axis at different radii so that the endless means of the accepting device moves faster. This allows safely removing the process good from a track of travel of a following pusher element before same tips downwards and could meet the process good. 
     The procedure described referring to  FIGS. 9   a  to  9   e  is suitable for all the systems in which a transport element follows a process good and, after delivery to an accepting device, turns around an axis. 
     By using intermediate transport systems, exemplarily the accepting/delivery device  206 , medium regions of upstream and downstream processing devices can be separated. In addition, the transport sections can be separated so that media can be prevented from being carried over from the processing stages. In addition, less material wearing of the transport system and synchronization of individual process transport sections can be achieved. It is also possible to use different materials for the individual transport sections. 
     As an alternative to the embodiments described, higher speed of an intermediate transport system may also be implemented using different means, exemplarily using a gear ratio via chains, gears, transmission, racks and the like. In addition, different drive systems and motors, which would then have to be synchronized, may be used. Intermediate transport systems may additionally be realized using rolls, bands, O-rings and the like. 
     Apart from a basically purely horizontal movement along a process path in a processing device, embodiments of the present invention thus also allow a basically horizontal movement of the process good through an entire system. With reference to  FIGS. 9   a  to  9   e , it may also be taken into consideration that the differences of the radii between the rolls of the processing devices and the accepting/delivery device can be reduced or compensated using the height of the rest elements. Embodiments of the present invention thus allow a basically horizontal movement through a processing system having several stages, wherein a basically horizontal movement exemplarily means a movement having a vertical component of no more than 5 mm. 
     Another embodiment of the invention which operates in correspondence with the principle described above referring to  FIG. 1   a  will be described subsequently referring to FIGS.  10   a  to  10   d .  FIG. 10   a  illustrates a schematic perspective view,  FIG. 10   b  schematically illustrates a side view in which, however, elements which would be covered by a lateral wall of the process medium reservoir can be recognized,  FIG. 10   c  illustrates a top view, and  FIG. 10   d  represents a sectional view along a line D-D in  FIG. 10   c.    
     In the embodiment shown in  FIGS. 10   a  to  10   d , a driving device includes two endless belts  300  traveling around rolls  302  and  304 . Two connecting carriers  306  and  308  are attached to the endless belts  300  spaced apart from each other. Transport elements which in  FIG. 10   b  are generally referred to by the reference numeral  310  which allow transport and guidance of the process good  10  project from connection carriers  306  and  308 . Four transport elements  310   a,    310   b,    310   c  and  310   d  which are attached to the transport element  306 , by means of which the process good  10  can be pushed in the direction of movement B, are shown in  FIG. 10   d . In addition, transport elements which allow lateral guidance of the process good may be provided, as is shown in  FIG. 10   d , by the two elements  310   e  and  310   f.  This means that the position of the process good in the direction of movement and transverse to the direction of movement (i.e. in the X direction and in the Y direction) can be determined by the corresponding elements. Additionally, suitable hold-down elements for the process good may be attached to the connection carriers  306 . 
     The endless belts may be driven in connection with the transport elements attached thereto using suitable driving means, such as, for example, a motor (not shown) which drives one of the axes of the rolls  302  and  304  so as to move the process good along a process path from being accepted by a delivery device to being delivered to an accepting device. 
     A process medium providing device in this embodiment may be of a setup comparable to the setup of the process medium providing device described referring to  FIGS. 8   a  to  8   d . Same elements here are referred to by the same reference numerals and need not be discussed further. In any case, the means for providing the process medium is again configured to produce a process medium projection  140  above the top surface of the perforated plate  134  such that the process good  10  can be introduced into the process medium projection laterally by means of the transport elements which move along the process path together with the process medium. 
     As can be particularly gathered from  FIGS. 10   c  and  10   d , grooves  320  which projections of the transport elements  310   a  to  310   f  engage are provided in the top surface of the perforated plate  134  comprising the openings  136 . This allows advantageously using these elements, for example when same do not transport any wafers for processing, to remove broken wafer parts from the process path. 
     In embodiments of the invention, the process good, for example the wafer or the substrate, is placed on a perforated plate and floats on a liquid film which is pressed through the holes of the perforated plate. A transport device here can push the process good over the perforated plate. This transport device can also immerse the process good below the surface of the process medium or process liquid. Zones between different processing stages, exemplarily between etching and cleaning or drying, may be realized using roll, air cushion or O-ring systems. The transport device may exemplarily be realized using a chain or a belt. 
     An embodiment of driving means of another embodiment of an inventive processing device which is based on the principle already described above referring to  FIGS. 3   a  and  3   b  will be discussed below referring to  FIGS. 11   a  to  11   c.    
     The transport means shown in  FIGS. 11   a  and  11   b  comprises an endless belt  400  to which hold elements in the form of pins  402  and  404  are attached. The pins  402  may be implemented to be longer than the pins  404 , wherein the process good may be positioned while resting on several of the pins  404  and leaning on the pins  402 . The endless belt  400  is arranged at an angle α relative to the vertical line, as can particularly be gathered from  FIG. 11   b . A process good or several process goods  10  can be processed individually one after the other by being placed on the pins  202  such that they are held in an inclined orientation, as can be gathered from  FIGS. 11   a  and  11   b.  The pins  402  and  404  thus act as a transport element which is moved along a process path together with the process good. 
     Not shown in  FIGS. 11   a  and  11   b  is process medium providing means which is arranged above the process path through which the process good is moved, as discussed before referring to  FIG. 3   b . A collecting reservoir for the process medium is schematically shown in  FIGS. 11   a  and  11   b  at  412 . By the driving means shown in  FIGS. 11   a  and  11   b,  the process good may be introduced laterally into a process medium volume produced by the process medium providing means arranged above the process path. 
       FIG. 11   c  schematically shows one way for process goods to travel between two processing stages of a setup, as is shown in  FIG. 11   a.  As is shown in  FIG. 11   c , such a delivery between corresponding devices may be done using O-rings. 
       FIGS. 12   a  and  12   b  show an embodiment of an accepting/delivery device which may be employed in inventive devices for processing a process good. When increased speed of an accepting/delivery device, as has been discussed referring to  FIGS. 9   a  to  9   e , is not necessary, instead an accepting/delivery device, as is shown in  FIGS. 12   a  and  12   b , may be used.  FIGS. 12   a  and  12   b  schematically show a first processing device  502 , a second processing device  504  and an accepting/delivery device  506 . The processing devices each comprise three endless devices  520 , such as, for example, endless belts or endless chains, arranged next to one another. The endless belts are each provided with rest elements  542 , in the manner shown in  FIGS. 12   a  and  12   b , for accepting a process good  10  to be handled, such as, for example, semiconductor wafers. As is shown in  FIGS. 12   a  and  12   b , the rest elements  542  comprise recesses at each corner thereof so as to allow process goods to be accepted one after the other (in the direction of the course of the endless devices  520 ) and also next to one another. In embodiments of the invention, rest elements may thus comprise a cross-shaped elevation by which the rest regions or stops for four process goods, such as, for example, semiconductor wafers, in the rest elements  542  are implemented. 
     The accepting/delivery device  506  in the embodiment shown in  FIGS. 12   a  and  12   b  includes an endless belt  550  which exemplarily comprises two rest elements  552 . The rest elements  552  comprise a central elevation which defines two rest areas for a front and a back process good. The elevation serves as a stop for a back process good and as a pusher for a front process good. 
     Rolls  554  on which the endless belt  550  of the accepting/delivery device  506  travels are attached to an axis  556  which rolls  558  on which the endless belts  520  travel are also attached to. The endless devices  550  of the accepting/delivery device  506  here engage between the endless devices  520  of the processing devices  502  and  504 . 
     When the first processing device  502  transports a process good  10  in a clockwise direction in a direction towards the accepting/delivery device  506 , the front end of the process good will come to rest on a corresponding recess of the rest element  552 . The rest elements  542  of the first processing device  502  then continue to push the process good until disengaging with the process good. When this is the case, the elevation of the second rest element  552  engages the back edge of the process good and continues to push the process good such that same becomes engaged with the recesses of the rest elements  542  of the second processing means  504 , as is shown for the right process good  10  in  FIGS. 12   a  and  12   b . The process good  10  is then continued to be pushed by the rest element  552  until the subsequent rest elements  542  of the front processing device become engaged with the back edge of the process good  10 . They continue to push the process good  10  such that the rest elements  552  may tip downwards. 
     In the embodiment of an accepting/delivery device shown in  FIGS. 12   a  and  12   b , rest elements  552  engage the process good  10  in a central position, while the rest elements  542  of the processing devices engage the process good  10  at the outer corners thereof. 
     As may also be gathered from  FIGS. 12   a  and  12   b , the rest elements may comprise beveled regions so as to allow smooth engagement of the process good  10 . 
     In embodiments of the invention, the process device may carry the process good to a section comprising a spray system so that liquid is sprayed or flooded onto the surface, wherein at the same time liquid can be flooded from below, and wherein the liquid can be re-circulated from an overflow tank to the spray system. 
     While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.