Method for shaping thin films in the near-edge regions of in-process semiconductor substrates

Abstract

A method for shaping and/or encapsulating near-edge regions of a substrate wafer is described. A housing provides channels for flowing a reactive gas towards the wafer edge. The reactive gas is directed towards the wafer edge for removing or depositing a thin film on the wafer edge. Gasses are exhausted downstream from the flow of the reactive gas. A second channel in the housing directs a flow of diluent/quenching gas onto the wafer for exhausting of the diluent/quenching gas and the reactive gas away from the wafer. The method may also provide a sequence of process steps, for example, selectively etching of a material on the wafer, etching of second material on the wafer and depositing an encapsulating material layer on the wafer.

1 . A method of processing a thin film on an edge of a substrate comprising the steps of: 
 mounting a substrate having a thin film thereon on a rotatable chuck;    directing a flow of reactive species through a channel in a housing angled towards the edge of the substrate; and    rotating the substrate relative to the flow of reactive species to process the thin film on the edge of the substrate.    
   
   
       2 . The method of  claim 1  wherein the channel is angled towards the edge of the substrate between greater than a vertical position and less than a horizontal position in relation to a top surface of the substrate.  
   
   
       3 . The method of  claim 1  further comprising the steps of: 
 directing a flow of diluent/quenching gas onto the substrate in a radially outward direction.    
   
   
       4 . The method of  claim 3  further comprising the steps of: 
 exhausting the flow of diluent/quenching gas from the substrate downstream of the flow of diluent/quenching gas.    
   
   
       5 . The method of  claim 1  further comprising the steps of: 
 directing a flow of diluent/quenching gas onto the substrate in a radially outward direction.    
   
   
       6 . The method of  claim 1  further comprising the steps of: 
 moving the substrate in a rectilinear direction relative to the flow of the reactive species to remove material from a thin film on the substrate while shaping the thin film to a predetermined shape.    
   
   
       7 . The method of  claim 1  wherein the reactive species comprises fluorine.  
   
   
       8 . The method of  claim 1  further comprising the steps of: 
 directing a flow of a second reactive species through a second channel in the housing angled towards the edge of the substrate for depositing a new thin film on the substrate.    
   
   
       9 . The method of  claim 8  further comprising the steps of: 
 directing a second flow of diluent/quenching gas onto the substrate in a radially outward direction.    
   
   
       10 . The method of  claim 1  further comprising the steps of: 
 directing a flow of a second reactive species through a second channel in the housing angled towards the edge of the substrate for depositing a new thin film on the substrate, wherein the second channel is co-radial with the channel, wherein the second channel is angled towards the edge of the substrate between greater than a vertical position and less than a horizontal position in relation to a top surface of the substrate; and    directing a second flow of diluent/quenching gas onto the substrate in a radially outward direction.    
   
   
       11 . The method of  claim 10  wherein the new thin film has a thickness in the range of from 0.1 to 0.3 μm.  
   
   
       12 . The method of  claim 1  further comprising the steps of: 
 collecting the reactive species in a plenum located about the edge of the substrate and exhausting the reactive species from said plenum.    
   
   
       13 . The method of  claim 1  further comprising the steps of: 
 generating the reactive species from a plasma source.    
   
   
       14 . The method of  claim 1  further comprising the steps of: 
 generating the reactive species from an atmospheric-pressure plasma jet.    
   
   
       15 . The method of  claim 1  wherein the thin film is a silicon dioxide.  
   
   
       16 . A method for processing a substrate comprising: 
 providing a housing having a plurality of channels for directing a flow of reactive species towards an edge of a substrate wherein the channels are radially angled in a direction towards the edge of the substrate;    flowing gases through at least one of the channels towards the edge of the substrate; and    exhausting exhaust gases downstream from the at least one of the channels.    
   
   
       17 . A method of shaping a thin film on a wafer comprising the steps of mounting a wafer having a thin film thereon on a rotatable chuck; 
 directing a flow of diluent/quenching gas onto the wafer in a radially outward direction;    exhausting the flow of diluent/quenching gas from the wafer downstream of the flow of diluent/quenching gas;    directing a flow of reactive gases towards the wafer radially outward of the diluent/quenching gas to react with the wafer; and    rotating the wafer relative to the flow of reactive gas to deposit a thin protective film of material on the edge of the wafer.    
   
   
       18 . A method as set forth in  claim 17  wherein the thin protective film has a thickness in the range of from 0.1 to 0.3 μm.  
   
   
       19 . A method of processing a wafer comprising the steps of: 
 rotating the wafer;    directing a flow of a first reactive species radially outward towards an edge of the wafer for etching the edge, wherein the first reactive species are directed through a first channel angled towards the edge; and    directing a flow of a second reactive species radially outward towards the edge of the wafer for deposition of a material on the edge, wherein the second reactive species are directed through a second channel angled towards the edge.    
   
   
       20 . The method of  claim 19  further comprising the steps of: 
 flowing a diluent/quenching gas radially outward towards the edge for preventing movement of the first reactive species radially inward, wherein the diluent/quenching gas originates from within the radial origin of the flow of the first reactive species.    
   
   
       21 . The method of  claim 19  further comprising the steps of: 
 providing a plurality of channels for directing the first reactive species towards near-edge, top bevel, crown, and bottom bevel of the wafer.