Abstract:
The invention relates to a device for processing of substrates, especially wafers, with at least one pretreatment module, at least one aftertreatment module and at least one primary treatment module, and the pretreatment module and the aftertreatment module can be switched as a lock for the primary treatment module, and a corresponding method for processing of substrates, especially wafers.

Description:
RELATED APPLICATIONS 
     The present application is a divisional of U.S. application Ser. No. 13/878,570, filed Apr. 10, 2013, which is a U.S. National Stage Application of International Application No. PCT/EP11/67405, filed Oct. 5, 2011, which claims priority from German Patent Application No. 10 2010 048 043.6, filed Oct. 15, 2010, said patent applications hereby fully incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a device for processing of substrates or substrate pairs, especially wafers as wafer pairs. 
     BACKGROUND OF THE INVENTION 
     Process systems or process devices of semiconductor technology are generally of modular structure. They conventionally consist of different chambers in which various process steps are carried out. Thus, for example for pretreatment of wafers, process steps such as wet cleaning, plasma treatment, etching or heating can be used, while for primary treatment of a wafer, bonding, lacquering, imprinting, embossing and exposure are possible. In known process systems the wafers or wafer stacks are transported with cassettes between the process systems or modules of process systems. 
     During transport, the contamination, damage, fouling or oxidation and thus influencing of other process steps can occur. 
     Contamination of the primary treatment chambers between treatments of successive wafers, therefore in loading and unloading of wafers, is also a problem. 
     Furthermore it is critical with respect to time that in the primary treatment large pressure differences from atmospheric pressure as far as very low pressures of 10 −6  bar or less must be overcome. 
     SUMMARY OF THE INVENTION 
     The object of this invention is therefore to optimize the processing of substrates both in terms of the sequence, and also to avoid contamination, damage, fouling or oxidation as much as possible. 
     This object is achieved with the features of the independent claims. Advantageous developments of the invention are given in the dependent claims. All combinations of at least two of the features given in the specification, the claims and/or the figures also fall within the framework of the invention. At the given value ranges, values within the indicated limits will also be disclosed as boundary values and will be claimed in any combination. 
     The invention is based on the idea of coupling a primary treatment module to at least one pretreatment module and at least one aftertreatment module such that at least one of the pretreatment modules and at least one of the aftertreatment modules and/or the primary treatment module each act as vacuum-tight locks for an adjacent pretreatment module, primary treatment module or aftertreatment module. At the same time, according to the invention in one embodiment of the invention it is provided that at least one of the pretreatment modules and/or the primary treatment module and/or at least one of the aftertreatment modules can be especially exposed to pressure, a vacuum, and/or can be temperature-treated, especially can be heated independently or regardless of an adjacent module. 
     In this way, in spite of a flexible structure of the process system according to the device as claimed in the invention a time-optimized, even parallel processing of several substrates is provided within the device as claimed in the invention, in which based on the lock-like coupling of the individual process modules contamination, damage, fouling or oxidation by decoupling of the substrates from external effects, especially in the loading and unloading of the individual modules, is resolved. 
     It is especially advantageous if the primary treatment module can be loaded and unloaded exclusively via locks or a positing system. This is achieved as claimed in the invention by there being both a pretreatment module which is coupled in the manner of a lock to the primary treatment module and also an aftertreatment module which is coupled in the manner of a lock to the primary treatment module. By this measure the generally especially critical primary treatment of the substrates or wafers which occurs under often extreme conditions does not take place at any instant of the processing nor during the loading and unloading of the primary treatment module with contact with the environment. The primary treatment module is accordingly completely decoupled from the environment so that contamination, damage, fouling or oxidation during the primary treatment of the substrates is essentially precluded. Furthermore, there is the advantage that the steps preparatory and subsequent to primary treatment can be moved into the pretreatment module and the aftertreatment module, especially at least partial exposure to pressure and/or temperature. In the primary treatment module as a result of this only a lower pressure difference and/or temperature difference than from the ambient/atmospheric pressure p ATM  need be overcome. 
     According to one advantageous embodiment of the invention, it is provided that the primary treatment chamber can be switched as a lock in the loading and unloading of the substrates. Thus, when the primary treatment chamber is being loaded, at the same time aftertreatment of the substrate which has been worked beforehand in the primary treatment chamber can take place. When the primary treatment chamber is being unloaded, conversely at the same time pretreatment of the next substrate which is to be worked in the primary treatment chamber can take place in the pretreatment chamber. 
     In another advantageous embodiment, it is provided that the pretreatment chamber and/or the primary treatment chamber and/or the aftertreatment chamber can be heated especially separately by means of a heating apparatus. It is especially advantageous here if the pretreatment chamber and/or the primary treatment chamber and/or the aftertreatment chamber are completely heat-insulated. In this way exact temperature control is possible with heat loss as low as possible. 
     To the extent other correspondingly made pretreatment modules can be connected upstream to the pretreatment module as locks and/or other correspondingly made aftertreatment modules can be connected downstream of the aftertreatment module as locks, the method sequence can be further subdivided so that optimization of the passage times in the process sequence arises. Here it is conceivable as claimed in the invention that at the same time several pretreatment modules are directly coupled to one pretreatment module via lock doors. In this way time-intensive pretreatment steps can proceed parallel and accordingly staggered in time in the upstream pretreatment modules. This applies analogously to the corresponding aftertreatment modules. 
     By the locks being made as pressure locks and/or temperature locks it is possible as claimed in the invention to control the pressure and/or the temperature by corresponding switching of the pretreatment modules and/or the aftertreatment modules. 
     For loading and unloading, as claimed in the invention there is a loading and unloading apparatus, especially at least one robot arm. The latter is used for loading and unloading of the substrates into/out of the primary treatment chamber and/or the pretreatment chamber and/or the aftertreatment chamber, and for parallel handling there can be several substrates/wafers in the process sequence, as claimed in the invention several robot arms. Thus for example in each pretreatment chamber and/or each aftertreatment chamber there can be exactly one robot arm which can engage the respectively adjacent pretreatment chamber and/or primary treatment chamber for loading and unloading of the respectively adjacent chambers when the respective lock door is opened. 
     According to one especially advantageous embodiment of the invention it is provided that the primary treatment chamber can be loaded at the same time from the pretreatment chamber and can be unloaded into the aftertreatment chamber and/or the pretreatment chamber and the aftertreatment chamber can be loaded at the same time via the first lock door and unloaded via the second lock door. 
     Other advantages, features and details of the invention will become apparent from the following description of preferred exemplary embodiments and using the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 a    shows a schematic plan view of a device as claimed in the invention with a pretreatment module, a primary treatment module and an aftertreatment module. 
         FIG. 1 b    shows a schematic sectional view of the device as claimed in the invention according to cutting line A-A from  FIG. 1   a,    
         FIG. 2 a    shows a schematic plan view of a second embodiment of the device as claimed in the invention with a pretreatment module, a primary treatment module and an aftertreatment module, 
         FIG. 2 b    shows a schematic sectional view of the device as claimed in the invention according to cutting line A-A from  FIG. 2   a,    
         FIG. 2 c    shows a schematic sectional view of the device as claimed in the invention according to cutting line B-B from  FIG. 2   a,    
         FIG. 3  shows a pressure/temperature diagram of a method as claimed in the invention for processing of substrates and 
         FIG. 4  shows a sectional view of the device as claimed in the invention with a pretreatment module, a primary treatment module and an aftertreatment module. 
         FIG. 5  shows a schematic plan view of an alternative embodiment of the device illustrated in  FIG. 1 a   , wherein the device includes two pretreatment modules for respective pretreatment of first and second wafers or first and second wafer pairs. 
     
    
    
     The same reference numbers for corresponding components are provided in the figures. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the embodiment of a device  1  as claimed in the invention shown in  FIG. 1  a pretreatment module  9 , a primary treatment module  10  and an aftertreatment module  11  are arranged linearly in a row. 
     The pretreatment module  9  consists of a pretreatment chamber  2  which can be exposed to a vacuum and which surrounds a pretreatment space  12 . A pressurization apparatus which is not shown is connected to the pretreatment chamber  2  and can be controlled by a central control apparatus  102  in order to be able to control the pressure in the pretreatment space  12  with the pretreatment chamber  2  closed. Via a temperature exposure apparatus  20 , the pretreatment space  12  can be heated and/or cooled, the temperature exposure apparatus  20  being controllable by the central control apparatus  102 . 
     To load the pretreatment module  9  with one (or more) wafers  15 , according to  FIG. 4  there is a first robot arm  16 . The latter, controlled from the central control apparatus  102 , can be routed through a first lock door  5  when the first lock door  5  is opened. Opening and closing of the first lock door  5  are likewise controlled by the central control apparatus  102 . 
     The first lock door  5  in the embodiment according to  FIGS. 1 a  and 1 b    is located on a first face side  18  of the device  1 . The first lock door  5  can be closed pressure-tight and has heat insulation so that the pretreatment space  12  in the closed state of the first lock door  5  can be pressurized. 
     Furthermore, the pretreatment chamber  2  opposite the first lock door  5  jointly with a primary treatment chamber  3  of the primary treatment module  10  has a first primary lock door  6 . The first primary lock door  6  is made functionally analogous to the first lock door  5 . The primary treatment module  10  can be coupled pressure-tight on the first primary lock door  6  to the pretreatment modules  9 , as a result of which a modular structure and a replacement of individual modules  9 ,  10 ,  11  of the device  1  can be implemented. 
     By controlling the first lock door  5  and the first primary lock door  6  by means of the central control apparatus  102 , the pretreatment module  9  can be used as a lock, specifically by the first lock door  5  being closed when the first lock door  6  is opened and vice versa. 
     The primary treatment module  10  consists of the primary treatment chamber  3  which encloses or forms a primary treatment space  13 . 
     Opposite the first primary lock door  6  of the primary treatment chamber  3  there is a second primary lock door  7  which is included at least partially in the primary treatment chamber  3  and which is used to unload the wafer  15  from the primary treatment chamber  3  into an aftertreatment chamber  4 . The second primary lock door  7  is formed at least partially by the aftertreatment chamber  4 . The primary treatment space  13  can be sealed pressure-tight by the second primary lock door  7  from one aftertreatment space  14  of the aftertreatment chamber  4 . Functionally the second primary lock door  7  corresponds to the first primary lock door  6 , the first primary lock door  6  and the second primary lock door  7 , controlled from the central control apparatus  102 , forming a lock. 
     The aftertreatment module  11  for aftertreatment of the wafer  15  after primary treatment in the primary treatment module  10  consists of the aftertreatment chamber  4  which forms the aftertreatment space  14 . Furthermore the aftertreatment chamber  4  has a second lock door  8  which is located opposite the second primary lock door  7 . 
     The wafer  15  can be unloaded via the second lock door  8  and by means of a second robot arm  17  after aftertreatment out of the aftertreatment space  14  as soon as the second lock door  8  is opened. 
     The aftertreatment module  11  can likewise act as a lock by the second primary lock door  7  being closed when the second lock door  8  is opened and vice versa. 
     The second lock door  8  is located on a second face side  19  of the device  1  so that a linear movement of the wafer  15  takes place during the entire process sequence through the pretreatment module  9 , the primary treatment module  10  and the aftertreatment module  11 . 
     The embodiment according to  FIG. 2 a    differs by the angular arrangement of the modules  9 ,  10 ,  11  so that an altered device  1 ′ results. Only the configuration of the primary treatment chamber  3 ′ is altered, since the second primary lock door  7  is not located opposite the first primary lock door  6 , but on one side wall of the primary treatment chamber  3 ′. 
     In another embodiment of the invention, in the embodiment according to  FIGS. 1 a  and 1 b    an additional side module (not shown) analogously to the aftertreatment module  11  in  FIG. 2 a    can be located laterally on the primary treatment module  10  in order to remove the damaged wafers which are detected during the process flow from the process sequence. 
     A process sequence as claimed in the invention whose pressure and temperature behavior is shown in  FIG. 3  proceeds as follows: 
     The first primary lock door  6  and the second primary lock door  7  are closed. Afterwards the pressure in the primary treatment space  13  is lowered by a pressurization apparatus which is not shown, for example a vacuum pump, especially to a pressure p min  less than 10 −6  bar, preferably to a pressure less than 10 −9  bar. This ideally takes place only a single time during the processing of a plurality, especially more than 100, preferably more than 1000, even more preferably more than 10000 wafers or wafer pairs. 
     Via the opened first lock door  5  a wafer  15  or wafer pair is loaded into the pretreatment chamber by means of the first robot arm  16  and is treated there. Pretreatment can be a dry and/or wet process step, for example wet cleaning, plasma treatment, etching, heating or the like. The pretreatment especially preferably comprises an especially optical and/or mechanical alignment apparatus. 
     Before or after or during the pretreatment step the pretreatment space  12  can be evacuated via a separately activated pressurization apparatus. 
     Before opening the first primary lock door  6 , in any case the first lock door  5  is closed and the pretreatment space  12  is evacuated, especially to a pressure p V , during or shortly prior to the loading of the pretreatment chamber  3  of less than 10 −6  bar, preferably less than 10 −7  bar, so that the pretreatment module  9  acts as a lock for the primary treatment module  10 . 
     The wafer  15  is loaded by an internal transport system, for example a robot arm, through the first primary lock door  6  into the primary treatment chamber  3 ,  3 ′. 
     Then the first primary lock door  6  is closed. During the loading of the primary treatment chamber  3 ,  3 ′ the second primary lock door  7  is continually closed. The pressure is preferably further lowered to p min  less than 10 −6  bar, even more preferably 10 −9  bar. 
     After closing the first primary lock door  6 , another wafer  15  can be loaded into the pretreatment chamber  2 . At the same time the primary treatment of the first wafer  15  takes place in the primary treatment module  10 . This can be for example bonding, lacquering, imprinting, embossing and/or exposure. 
     After the primary treatment of the wafer  15  in the primary treatment module  10 , the wafer  15  is loaded into the aftertreatment module  11  by opening the second primary lock door  7 , the second lock door  8  being closed. Before opening of the second primary lock door  7  the aftertreatment space  14  is exposed to a vacuum, especially a pressure p N  of less than 10 −6 , preferably less than 10 −7  by a pressurization apparatus of the aftertreatment module  11  at least until the wafer  15  is loaded from the primary treatment module  10  into the aftertreatment module  11  and the second primary lock door  7  is closed again. 
     Then aftertreatment of the wafer  15  takes place in the aftertreatment module  11 , for example cooling and simultaneous raising of the pressure by the pressurization apparatus of the aftertreatment module  11 . 
     After completion of the aftertreatment of the wafer  15  in the aftertreatment module  11 , the wafer  15  is removed via the second lock door  8  and the second robot arm  17 . 
     Before each opening of the primary lock door  6  the pretreatment chamber  2 , and before each opening of the primary lock door  7  the aftertreatment chamber  4  are exposed to a pressure p V  or p N  less than the atmospheric and/or ambient pressure P ATM  outside the chambers  2 ,  3 ,  4  and/or decontaminated, especially flushed with inert gas. 
     According to one especially advantageous embodiment of the above described invention, the wafer  15  is a wafer pair and a wafer pair is loaded into the device  1  in the above described manner by means of a holding device or handling apparatus for handling of the wafer pair, the pretreatment shown in the left-hand section in  FIG. 3  comprising the steps heating, evacuation, gas flushing with reducing gas, a wet chemical treatment, a plasma treatment and/or argon bombardment. 
     The primary treatment takes place in a vacuum which is higher compared to pretreatment, therefore at a lower pressure p min  as is shown in  FIG. 3  in the middle section. A controlled gas atmosphere, therefore an exactly set gas pressure and an exactly controlled mixing ratio of gases are set by the pressurization apparatus of the primary treatment module  10 . Then the wafer pair is brought into contact and bonded. Beforehand, the temperature which is necessary for the joining, especially T max , is set to be greater than 250° C., preferably T max  greater than 400° C. During bonding, a force as uniform as possible is applied to the wafer pair and/or an electrical voltage is applied. 
     The aftertreatment which is shown in  FIG. 3  in the right-hand section, takes place in an nonoxidizing environment, in which cooling takes place and the pressure is raised to atmospheric pressure. Slow cooling prevents or avoids thermal stresses in the wafer pair which was bonded beforehand. 
     The pretreatment of the wafer pair can take place according to an embodiment shown in  FIG. 5 . Device  1 ″ includes a first pretreatment module  9   a  for pretreatment of the first wafer W 1  or wafer pair and a second pretreatment module  9   b  for pretreatment of the second wafer W 2  or wafer pair. The first and the second wafers W 1 , W 2  can be loaded into the primary treatment chamber via separate lock doors. 
     The chambers  2 ,  3 ,  4  are preferably made of stainless steel or aluminum. 
     In the embodiment shown in  FIG. 4 , the first lock door  5  is not located on the face side  18  of the pretreatment chamber  2 ′, but on the side wall. The second lock door  8  is not located on the face side  19 , but on the side wall of the aftertreatment chamber  4 ′. 
     The process flow is shown by arrows in  FIG. 4 . 
     The primary lock doors  6 ,  7  must accordingly have high pressure tightness up to p min  and are preferably made as a transfer valve which is or can be inserted in a common channel between the respectively adjacent chambers  2 ,  3 ,  4 , forming a seal. The opening diameter of the lock doors  5 ,  6 ,  7 ,  8  is more than 200 min, especially more than 300 mm, preferably more than 450 mm. 
     REFERENCE NUMBER LIST 
     
         
           1 ,  1 ′,  1 ″ device 
           2 ,  2 ′ pretreatment chamber 
           3 ,  3 ′ primary treatment chamber 
           4 ,  4 ′ aftertreatment chamber 
           5  first lock door 
           6  first primary lock door 
           7  second primary lock door 
           8  second lock door 
           9  pretreatment module 
           10  primary treatment module 
           11  aftertreatment module 
           12  pretreatment space 
           13  primary treatment space 
           14  aftertreatment space 
           15  wafer 
           16  first robot arm 
           17  second robot arm 
           18  first face side 
           19  second face side 
           20  temperature exposure apparatus 
           102  central control apparatus