Vacuum pumping arrangement

Abstract

A vacuum pumping arrangement comprising multiple pumping stages for evacuating a process chamber and a method of cleaning the vacuum pumping arrangement is discussed. The vacuum pumping arrangement comprises: at least one turbomolecular pumping stage; at least one further pumping stage downstream of the turbomolecular pumping stage; and at least one inlet for admitting radicals into the vacuum pumping arrangement, the at least one inlet being located downstream of the turbomolecular stage and upstream of at least one of the at least one further pumping stage.

1 . A vacuum pumping arrangement comprising multiple pumping stages for evacuating a process chamber, said vacuum pumping arrangement comprising:
 at least one turbomolecular pumping stage;   at least one further pumping stage downstream of said turbomolecular pumping stage, at least one of said at least one further pumping stages comprising a drag pumping stage; and   at least one inlet configured to admit radicals into said vacuum pumping arrangement, said at least one inlet being located downstream of said turbomolecular stage and upstream of said drag pumping stage; wherein   said vacuum pumping arrangement comprises a single shaft multistage pump, each of said multiple stages being mounted on a same shaft and said at least one inlet comprising an inter-stage inlet between said stages.   
     
     
         2 . The vacuum pumping arrangement according to  claim 1 ,
 wherein at least one of said at least one inlets comprises an inlet between said turbomolecular stage and a pumping stage immediately downstream of said turbomolecular pumping stage.   
     
     
         3 . The vacuum pumping arrangement according to  claim 1 , wherein said at least one further pumping stage comprise a plurality of further pumping stages, said plurality of further pumping stages comprising at least one regenerative pumping stage and said at least one drag pumping stage. 
     
     
         4 . The vacuum pumping arrangement according to  claim 1 , wherein said drag stage is adjacent to said at least one turbomolecular stage and said inlet is located between said at least one turbomolecular stage and said drag stage. 
     
     
         5 . The vacuum pumping arrangement according to  claim 1 , said vacuum pumping arrangement further comprising a radical source for generating said radicals connected to said at least one inlet. 
     
     
         6 . A The vacuum pumping arrangement according to  claim 5 , wherein said radical source comprises a plasma source for generating a plasma. 
     
     
         7 . The vacuum pumping arrangement according to  claim 1 , said vacuum pumping arrangement comprising control circuitry, said control circuitry being configured to control input of said radicals via said inlet. 
     
     
         8 . The vacuum pumping arrangement according to  claim 1 , said vacuum pumping arrangement comprising control circuitry, said control circuitry being configured to control input of said radicals via said inlet in response to an indication that a process in said process chamber is not active. 
     
     
         9 . The vacuum pumping arrangement according to  claim 7 , said control circuitry comprising an input for receiving signals from a controller of said process chamber, said control circuitry being configured to control input of said radicals via said inlet in response to receipt of a signal indicating said process chamber is commencing a cleaning cycle. 
     
     
         10 . The vacuum pumping arrangement according to  claim 7 , said control circuitry comprising an input for receiving signals from a controller of said process chamber, said control circuitry being configured to control input of said radicals via said inlet in response to receipt of a signal indicating a wafer in said process chamber is being changed. 
     
     
         11 . The vacuum pumping arrangement according to  claim 7 , said inlet comprising a valve, said control circuitry being operable to control input of said radicals via said inlet by controlling said valve. 
     
     
         12 . The vacuum pumping arrangement according to  claim 7 , said control circuitry being configured to control a motor driving said rotor of said multiple pumping stages. 
     
     
         13 . The vacuum pumping arrangement according to  claim 1 , said inlet being arranged such that said radicals are injected into said pumping arrangement in a region having viscous fluid flow and downstream of a region having molecular fluid flow. 
     
     
         14 . The vacuum pumping arrangement according to  claim 1 , wherein said radicals comprise at least one of: Cl. generated from a chloride, F., generated from F2 thermally or generated by a plasma source from NF3, SF6, C5F8, or O. generated from O2, O3 or H2O. 
     
     
         15 . The vacuum pumping arrangement according to  claim 13 , said vacuum pump arrangement further comprising a radical source for generating said radicals prior to injection via said inlet, said radical source comprising a source of BCl3 or SiCl4 for generating said chloride radicals.