Plasma Spreading Apparatus And System

Abstract

A device and method of spreading plasma which allows for plasma etching over a larger range of process chamber pressures. A plasma source, such as a linear inductive plasma source, may be choked to alter back pressure within the plasma source. The plasma may then be spread around a deflecting disc which spreads the plasma under a dome which then allows for very even plasma etch rates across the surface of a substrate. The apparatus may include a linear inductive plasma source above a plasma spreading portion which spreads plasma across a horizontally configured wafer or other substrate. The substrate support may include heating elements adapted to enhance the etching.

What is claimed is: 
     
         1 . A plasma etching process chamber, said plasma etching process chamber comprising:
 a plasma source, said plasma source comprising a first end and a second end, said first end comprising a gas input portion, said plasma source coupled to a process chamber at a second end;   a process chamber;   a constricting plate adapted to constrict the flow of plasma from said plasma source, said constricting plate at said second end of said plasma source, said constricting plate comprising an annulus;   a spreading disc, said spreading disc adapted to spread the flow of plasma after the plasma has flowed through said constricting plate, said spreading disc disposed between said constricting plate and the substrate support, said spreading disc centered below said annulus of said constricting plate;   a substrate support, said support adapted to support a substrate in the spread plasma flow, said substrate support residing within said process chamber, said substrate support centered below said spreading disc; and   a vacuum system, said vacuum system adapted to evacuate said process chamber.   
     
     
         2 . The plasma etching process chamber of  claim 1  wherein said plasma source is a linear-inductive plasma source. 
     
     
         3 . The plasma etching process chamber of  claim 2  wherein said plasma source has a cylindrical plasma chamber. 
     
     
         4 . The plasma etching process chamber of  claim 3  wherein said constricting plate comprises a disc with an annulus, said disc extending from an inner surface of said cylindrical plasma chamber. 
     
     
         5 . The plasma etching process chamber of  claim 4  wherein the ratio of the diameter of the annulus in the constrictor plate to the interior diameter of the cylindrical plasma chamber is in the range of 1:8 to 1:3. 
     
     
         6 . The plasma etching process chamber of  claim 4  wherein the ratio of the diameter of the annulus in the constrictor plate to the interior diameter of the cylindrical plasma chamber is in the range of 1:5 to 1:2.5. 
     
     
         7 . The plasma etching process chamber of  claim 1  further comprising a gas input showerhead, said gas input showerhead at the first end of said plasma source. 
     
     
         8 . The plasma etching process chamber of  claim 4  further comprising a gas input showerhead, said gas input showerhead at the first end of said plasma source. 
     
     
         9 . The plasma etching process chamber of  claim 4  wherein said spreading disc is circular, and wherein the diameter of the spreading disc is larger than the diameter of the annulus in the constrictor plate. 
     
     
         10 . The plasma etching process chamber of  claim 5  wherein said spreading disc is circular, and wherein the diameter of the spreading disc is larger than the diameter of the annulus in the constrictor plate. 
     
     
         11 . The plasma etching process chamber of  claim 10  wherein said spreading disc comprises a curved surface facing said constrictor plate.