Systems and Methods Utilizing an Aperture with a Reactive Atom Plasma Torch

Abstract

A method for reducing heat applied to a workpiece by a plasma discharge of a reactive plasma torch comprises determining a footprint of the plasma discharge on a surface of the workpiece based on a distance of the reactive atom plasma torch from the surface, determining a maximum heat absorbable by the workpiece, and determining an adjusted footprint of the reactive atom plasma torch on the surface based on the maximum heat absorbable by the workpiece. An aperture of an aperture device is selected based on the adjusted footprint of the reactive atom plasma torch. The aperture device is then positioned so that a portion of the plasma is one or both of deflected and absorbed by the aperture device, thereby reducing the heat absorbed by the workpiece.

1 . A method for reducing heat applied to a workpiece by a plasma discharge of a reactive atom plasma torch, comprising: 
 determining a footprint of the plasma discharge on a surface of the workpiece based on a distance of the reactive atom plasma torch from the surface;    determining a maximum heat absorbable by the workpiece;    determining an adjusted footprint of the reactive atom plasma torch on the surface based on the maximum heat absorbable by the workpiece;    selecting an aperture of an aperture device based on the adjusted footprint of the reactive atom plasma torch;    positioning the aperture device so that a portion of the plasma is one or both of deflected and absorbed by the aperture device, thereby reducing the heat absorbed by the workpiece.    
     
     
         2 . A method according to  claim 1 , wherein: 
 the footprint of the plasma discharge is approximately circular; and    the adjusted footprint of the plasma discharge has a smaller diameter than the footprint.    
     
     
         3 . A method according to  claim 1 , further comprising: 
 using the portion of the plasma passing through the aperture to modify the surface of the workpiece, the surface of the workpiece containing a material that can chemically combine with a reactive species generated from the reactive precursor and leave the surface of the workpiece.    
     
     
         4 . A method according to  claim 1 , further comprising: 
 altering a shape of the portion of the plasma passing through the aperture.    
     
     
         5 . A method according to  claim 1 , further comprising: 
 maintaining the plasma at about atmospheric pressure.    
     
     
         6 . A method according to  claim 2 , further comprising: 
 varying a diameter of the aperture of the aperture device based on the adjusted footprint.    
     
     
         7 . A method according to  claim 1 , further comprising: 
 using a temperature-reducing device to reduce the temperature of the aperture device.    
     
     
         8 . A method according to  claim 7 , wherein: 
 the temperature-reducing device includes an electrically-isolated water chiller capable of circulating cooled liquid about the aperture.    
     
     
         9 . A method according to  claim 1 , wherein: 
 the aperture is selected from the group consisting of single holes, single slits, multiple holes, non-circular openings, irregular shapes, and regular shapes.    
     
     
         10 . A method according to  claim 1 , wherein selecting the aperture further comprises: 
 selecting the aperture from a plurality of apertures rotatably arranged in the aperture device, the plurality of apertures having one or both of different shapes and different sizes.    
     
     
         11 . A method according to  claim 1 , further comprising: 
 selecting a reactive atom plasma torch from the group consisting of inductively coupled plasma (ICP) torch, microwave-induced plasma (MIP) torch, and flame torch.    
     
     
         12 . A tool for modifying a surface of a workpiece, comprising: 
 a reactive atom plasma torch including a plasma discharge having a footprint;    an aperture device positionable between the reactive atom plasma torch and the surface of the workpiece so that a portion of the plasma discharge is one or both of deflected and absorbed by the aperture device; and    a controller adapted to determine one or both of an aperture size and a position of the aperture device based on a maximum absorbable heat of the workpiece.    
     
     
         13 . The tool of  claim 12 , wherein the aperture device is made of a material selected from the group consisting of high-temperature metals and high-temperature ceramics.  
     
     
         14 . The tool of  claim 12 , further comprising: 
 an insulated rod capable of supporting the aperture device in order to electrically isolate the aperture device.    
     
     
         15 . The tool of  claim 12 , further comprising: 
 a temperature-reducing device capable of reducing the temperature of the aperture device.    
     
     
         16 . The tool of  claim 15 , wherein: 
 the temperature-reducing device includes an electrically-isolated water chiller capable of circulating cooled liquid about the aperture.    
     
     
         17 . The tool of  claim 12 , further comprising: 
 at least one channel positioned about the aperture in the aperture device, the channel capable of carrying at least one of a liquid and a gas capable of removing heat from the aperture device.    
     
     
         18 . The tool of  claim 12 , wherein the aperture device includes a plurality of apertures differing by one or both of size and shape, an aperture being selectable for use with the reactive atom plasma torch from the plurality of apertures.  
     
     
         19 . A method for modifying the active footprint of a reactive atom plasma torch applied to a workpiece, comprising: 
 determining a modified footprint based on a maximum absorbable heat of the workpiece;    selecting one or both of an aperture size and a target distance of the aperture from one or both of the reactive atom plasma torch and a surface of the workpiece based on the modified footprint;    using a plasma torch to inject a reactive precursor into the plasma to generate a reactive species; and    positioning the aperture and the plasma torch so that a portion of the plasma having the modified footprint passes through the aperture and affects a surface of a workpiece.    
     
     
         20 . The method of  claim 19 , further comprising one or more of: 
 shaping the surface of the workpiece with the portion of the plasma having the modified footprint;    polishing the surface of the workpiece with the portion of the plasma having the modified footprint;    planarizing the surface of the workpiece with the portion of the plasma having the modified footprint; and    cleaning the surface of the workpiece with the portion of the plasma having the modified footprint.