Vacuum-processing chamber-shield and multi-chamber pumping method

Abstract

One or more chambers of a multi-chamber vacuum processing apparatus are provided with a high gas flow conductance path to an exhaust volume of the apparatus that is maintained at high vacuum with a high vacuum pump. Separate pumps for the one or more chambers are made unnecessary by providing such chambers with a protective deposition shield or shield set that is configured to substantially protect walls of the chamber and the gas flow conductance path from deposition and to partially impede the gas flow from the chamber through the gas flow conductance path to the exhaust volume so that the chamber can be operated at a higher pressure than that of the exhaust volume and the chambers can be operated at different pressures and without cross-contamination. Preferably, a nested set of chamber shields is used. A controller is programmed to control the processing of wafers in the chambers by controlling the supply of process gas into the chambers.

1 . A set of replaceable protective deposition shields for a PVD processing chamber comprising: 
 an outer shield having a generally cylindrical portion and a gas outlet opening therethrough and a gas inlet opening therethrough;    an inner shield having a generally cylindrical portion of a diameter less than that of the generally cylindrical portion of the outer shield and having an inlet opening therethrough for alignment with the inlet opening of the outer shield; and    the inner shield being configured to mount in a nested relationship with the outer so as to form an annular gap between the inner and outer shields that communicates with the opening and that extends sufficiently from the opening so as to require at least three specular reflections off shield surfaces of atoms of coating material moving from the chamber to the opening when the set is installed in a process chamber and a PVD process is being performed in the process chamber.    
   
   
       2 . Two sets of replaceable protective deposition shields of  claim 1 , each set being differently configured so as to differently impede gas flow from the chambers.  
   
   
       3 . A PVD apparatus comprising the protective set of replaceable deposition shields of  claim 1  and further comprising: 
 a plurality of single-wafer processing chambers;    a high vacuum pump;    an exhaust volume communicating with the high vacuum pump; and    a gas flow conductance path extending from at least one of the chambers to the exhaust volume; and    the protective set of replaceable deposition shields being installed in the at least one of the chambers with the opening in the outer shield aligned with the gas flow conductance path.    
   
   
       4 . The PVD apparatus of  claim 3  further comprising: 
 a processing gas supply connected to the at least one of the chambers; and    a controller programmed to control the processing of wafers in the chambers by controlling the supply of process gas into at least said one of the chambers such that gas flows from the chamber, through the path and to the exhaust volume, and such that the chamber is maintained at a controlled processing pressure that is higher than the pressure at the exhaust volume.    
   
   
       5 . The PVD apparatus of  claim 3  further comprising: 
 a gas flow conductance path extending from at least two of the chambers to the exhaust volume; and    a protective set of replaceable deposition shields being installed in the at least two of the chambers with the opening in the outer shield of the set aligned with the gas flow conductance path from the chamber.    
   
   
       6 . The PVD apparatus of  claim 5  further comprising: 
 a processing gas supply connected to each of the at least two of the chambers; and    a controller programmed to control the processing of wafers in the chambers by controlling the supply of process gas into each of the at least two of the chambers such that gas flows from the chamber, through the path and to the exhaust volume, and such that each of the at least two chambers is maintained at a different controlled processing pressure that is higher than the pressure at the exhaust volume.    
   
   
       7 . A PVD apparatus comprising: 
 a plurality of single-wafer processing chambers bounded by chamber walls;    a high vacuum pump;    an exhaust volume communicating with the high vacuum pump;    a gas flow conductance path extending from at least one of the chambers to the exhaust volume;    a protective deposition shield installed in the at least one of the chambers configured to substantially protect walls of the chamber and the gas flow conductance path from deposition from the chamber, and to partially impede the gas flow from the chamber through the gas flow conductance path to the exhaust volume so that the chamber can be operated at a higher pressure than that of the exhaust volume; and    a controller programmed to control the processing of wafers in the chambers by controlling the supply of process gas into said one of the chambers such that gas flows from the chamber, through the path and to the exhaust volume, and such that the chamber can be maintained at a controlled processing pressure that is higher than the pressure at the exhaust volume.    
   
   
       8 . The PVD apparatus of  claim 7  further comprising: 
 a processing gas supply connected to the at least one of the chambers; and    the controller being programmed to control the processing of wafers in the chambers by controlling the supply of process gas into at least said one of the chambers such that gas flows from the chamber, through the path and to the exhaust volume, and such that the chamber is maintained at a controlled processing pressure that is higher than the pressure at the exhaust volume.    
   
   
       9 . The PVD apparatus of  claim 7  further comprising: 
 a gas flow conductance path extending from at least two of the chambers to the exhaust volume;    a protective deposition shield being installed in the at least two of the chambers configured to substantially protect walls of the respective chambers and the gas flow conductance paths from deposition from the chambers, and to partially impede the gas flow from the chambers through the gas flow conductance paths to the exhaust volume so that each chamber can be operated at a higher pressure than that of the exhaust volume; and    the controller being programmed to control the processing of wafers in the chambers by controlling the supply of process gas into each of said two of the chambers such that gas flows from the chamber, through the respective path and to the exhaust volume, and such that each chamber is maintained at a different controlled processing pressure that is higher than the pressure at the exhaust volume.    
   
   
       10 . The PVD apparatus of  claim 9  further comprising: 
 a plenum having an index plate lying in a vertical plane and mounted to rotate on a horizontal axis therein, a plurality of wafer holders being spaced around the axis on the index plate;    the plurality of single-wafer processing chambers being spaced at intervals around the plenum for alignment with holders on the index plate;    a plurality of gas flow conductance paths each extending from each of the at least two of the chambers to the exhaust volume; and    each of the at least two chambers having a protective deposition shield installed therein configured to substantially protect walls of the chamber and the gas flow conductance path from deposition from the chamber, and to partially impede the gas flow from the chamber through the gas flow conductance path to the exhaust volume so that the at least two chambers can be operated at different pressures, at least one being higher than that of the exhaust volume.    
   
   
       11 . The PVD apparatus of  claim 7  further comprising: 
 a wafer processing module having the at least one chamber therein;    a transfer module removably connected to the processing module and having the exhaust volume therein to which the chamber of the processing module is connected through the flow conductance path; and    the controller being programmed to control the processing of wafers in the chamber in the processing module by controlling the supply of process gas into said chamber such that gas flows from the chamber, through the path and to the exhaust volume, and such that the chamber is maintained at a controlled processing pressure that is higher than the pressure at the exhaust volume.    
   
   
       12 . The PVD apparatus of  claim 11  wherein: 
 the transfer module includes a transfer arm moveable to pass a wafer between the transfer module and the processing module through the flow conductance path;    the protective deposition shield being moveable in response to the controller to so partially impede the gas flow from the chamber through the gas flow conductance path to the exhaust volume during processing in the processing module and away from the gas flow path when a wafer is being passed therethrough.    
   
   
       13 . The PVD apparatus of  claim 12  further comprising: 
 a baffle moveable with the shield into and out of the gas flow path.    
   
   
       14 . The PVD apparatus of  claim 7  further comprising: 
 at least two wafer processing modules, each having a chamber therein;    a transfer module removably connected to each processing module and having the exhaust volume therein;    each processing module having a flow conductance path connecting the chamber thereof to the exhaust volume;    the chamber of each processing module having a shield therein configured to substantially protect walls of the chamber and the respective gas flow conductance path from deposition from the chamber, and to partially impede the gas flow from the respective chamber through the respective gas flow conductance path to the exhaust volume; and    the controller being programmed to control the processing of wafers in the chambers in the processing modules by controlling the supply of process gas into said chambers such that gas flows from the respective chamber, through the respective path and to the exhaust volume, and such that the pressure in one chamber is maintained at a controlled processing pressure that is higher than the pressure in another chamber.    
   
   
       15 . The PVD apparatus of  claim 14  further comprising: 
 the transfer module includes a transfer arm moveable to pass a wafer between the transfer module and the processing modules through the respective flow conductance paths thereof;    the protective deposition shields in each processing module being moveable in response to the controller to so partially impede the gas flow from the chamber through the gas flow conductance path to the exhaust volume during processing in the processing module and away from the gas flow path when a wafer is being passed therethrough;    one of the processing modules being configured to perform a process therein at a pressure that is higher than that of the other processing module and provided with a baffle moveable with the shield therein into and out of the gas flow path.