Bare aluminum baffles for resist stripping chambers

Abstract

Bare aluminum baffles are adapted for resist stripping chambers and include an outer aluminum oxide layer, which can be a native aluminum oxide layer or a layer formed by chemically treating a new or used bare aluminum baffle to form a thin outer aluminum oxide layer.

1 . A bare aluminum baffle adapted for a plasma processing apparatus comprising a resist stripping chamber and a remote plasma source operable to supply reactive species into the resist stripping chamber, wherein the baffle is configured to be supported by a sidewall of the resist stripping chamber and form a top wall of the resist stripping chamber, the baffle including gas passages for distributing the reactive species.  
   
   
       2 . The bare aluminum baffle of  claim 1 , comprising an outer aluminum oxide layer forming the outer surface of the bare aluminum baffle and having a thickness of about 50 angstroms to about 300 angstroms and a density of at least about 90% of the theoretical density of aluminum oxide.  
   
   
       3 . The bare aluminum baffle of  claim 2 , wherein the outer aluminum oxide layer has a thickness of about 50 angstroms to about 100 angstroms and a density of at least about 95% of the theoretical density of aluminum oxide.  
   
   
       4 . The bare aluminum baffle of  claim 1 , comprising an outer native aluminum oxide layer having a thickness of from about 25 to about 75 angstroms.  
   
   
       5 . The bare aluminum baffle of  claim 1 , comprising an inner portion and a peripheral portion, wherein the inner portion includes a central projection and a plurality of concentrically arranged rows of the gas passages surrounding the central projection, the central projection includes an upper surface and a plurality of through passages oriented at an acute angle relative to the upper surface such that the through passages extend in radial outward directions toward the peripheral portion, and the peripheral portion includes a flange having holes adapted to receive fasteners to attach the baffle to the sidewall.  
   
   
       6 . The bare aluminum baffle of  claim 1 , wherein the bare aluminum baffle is adapted to support a bare aluminum liner on a plurality of liner supports on an upper surface of the bare aluminum baffle such that the liner is adjacent to a cover of the resist stripping chamber and a plenum is defined between a bottom surface of the liner and an upper surface of the bare aluminum baffle when the bare aluminum baffle is supported on the side wall, the plenum being in fluid communication with the remote plasma source and the resist stripping chamber.  
   
   
       7 . The bare aluminum baffle of  claim 1 , which is of an aluminum alloy.  
   
   
       8 . The bare aluminum baffle of  claim 1 , which is circular shaped and has a diameter which is larger than a width of the interior of the resist stripping chamber so that a peripheral portion of the baffle overlies the side wall when the baffle is supported on the side wall of the resist stripping chamber.  
   
   
       9 . A resist stripping apparatus, comprising: 
 a resist stripping chamber;    a remote plasma source operable to generate a plasma and introduce reactive species into the resist stripping chamber; and    a bare aluminum baffle according to  claim 1  supported by a sidewall of the resist stripping chamber and forming a top wall of the resist stripping chamber.    
   
   
       10 . The resist stripping apparatus of  claim 9 , wherein the remote plasma source includes a microwave generator adapted to emit microwaves to excite a process gas into the plasma state.  
   
   
       11 . A method of stripping resist from a substrate in a resist stripping chamber, the method comprising: 
 energizing a process gas into the plasma state remotely from the resist stripping chamber and supplying reactive species into the resist stripping chamber in which a semiconductor substrate including a resist is supported on a substrate support, the resist stripping chamber including a sidewall and a bare aluminum baffle according to  claim 1  supported by the sidewall and forming a top wall of the resist stripping chamber; and    distributing the reactive species onto the substrate through gas passages in the baffle so as to remove the resist from the substrate.    
   
   
       12 . The method of  claim 11 , wherein the baffle comprises an outer aluminum oxide layer having a thickness of about 50 angstroms to about 300 angstroms and a density of at least about 90% of the theoretical density of aluminum oxide.  
   
   
       13 . The method of  claim 11 , wherein the baffle comprises an outer native aluminum oxide layer having a thickness of from about 25 to about 75 angstroms.  
   
   
       14 . The method of  claim 11 , wherein the process gas comprises oxygen and fluorine.  
   
   
       15 . A method of treating a bare aluminum baffle adapted for a resist stripping chamber, comprising: 
 a) treating a bare aluminum baffle having a first outer aluminum oxide layer with a chemical solution which is effective to remove contaminants and the first outer aluminum oxide layer from the baffle to expose aluminum material; and    b) forming a second outer aluminum oxide layer on the aluminum material, the second outer aluminum oxide layer having a thickness of about 50 angstroms to about 300 angstroms and a density of at least about 90% of the theoretical density of aluminum oxide.    
   
   
       16 . The method of  claim 15 , wherein the second outer aluminum oxide layer has a thickness of about 50 angstroms to about 100 angstroms and a density of at least about 95% of the theoretical density of aluminum oxide.  
   
   
       17 . The method of  claim 15 , wherein the first outer aluminum oxide layer is a native aluminum oxide layer.  
   
   
       18 . The method of  claim 15 , further comprising, between a) and b), refinishing the surface of the bare aluminum baffle.  
   
   
       19 . The method of  claim 15 , wherein the second aluminum oxide layer is formed on the aluminum material by an electropolishing procedure.  
   
   
       20 . The method of  claim 15 , wherein the aluminum material is an aluminum alloy.