Plasma mediated ashing processes that include formation of a protective layer before and/or during the plasma mediated ashing process

Abstract

Processes for stripping high dose ion implanted photoresist while minimizing substrate loss. The processes generally include passivation of the substrate surface before and/or during a plasma mediated stripping process. By passivating the substrate surface before and/or during the plasma mediated stripping process, oxidation is substantially reduced during plasma stripping thereby leading to reduced substrate loss.

1 . A process for reducing the loss of substrate material in a plasma mediated photoresist stripping process, the process comprising:
 providing a substrate having at least a portion of a surface covered with a material;   forming a protective layer on the surfaces free of the material before and/or during the photoresist stripping process, wherein forming the protective layer comprises exposing the substrate to plasma formed from a nitrogen containing gas and/or a carbon containing gas or exposing the substrate to ultraviolet radiation in the presence of the nitrogen containing gas and/or the carbon containing gas;   simultaneously removing at least a portion of the material with the plasma mediated stripping process and the protective layer; and   repeating the steps of forming the protective layer and removing the at least portion of the material disposed thereon until a desired thickness of the material is removed.   
     
     
         2 . The process of  claim 1 , wherein the material is a photoresist and/or an anti-reflective coating. 
     
     
         3 . The process of  claim 1 , wherein forming the protective layer comprises depositing the protective layer onto the surfaces free of the material. 
     
     
         4 . The process of  claim 1 , wherein forming the protective layer comprises passivating the surfaces free of the material. 
     
     
         5 . The process of  claim 1 , wherein the nitrogen containing gas comprises N 2 , NH 3 , NO, N 2 O 3 , N 2 O, nitrogen containing hydrocarbons, or mixtures thereof. 
     
     
         6 . The process of  claim 1 , wherein the carbon containing gas comprises CO 2 , CH 4 , HCN, C 2 O, CO or mixtures thereof. 
     
     
         7 . The process of  claim 1 , wherein the plasma mediated process comprises exposing the substrate to an oxygen based plasma. 
     
     
         8 . The process of  claim 1 , wherein the plasma mediated stripping process comprises exposing the substrate to an oxygen based plasma. 
     
     
         9 . The process of  claim 1 , wherein each one of the steps for forming the protective layer and removing the at least portion of the material is less than one second. 
     
     
         10 . A process for reducing the loss of substrate material in a plasma mediated stripping process, the process comprising:
 providing a substrate including a mask of an organic material disposed thereon;   forming a protective layer on an exposed surface of the substrate without the mask before and/or during the photoresist stripping process, wherein forming the protective layer comprises exposing the surface to ultraviolet radiation in the presence of an inert gas or a nitrogen containing gas or a carbon containing gas or mixtures thereof,   removing at least a portion of the mask and the protective layer with the plasma mediated stripping process; and   repeating the steps of forming the protective layer and removing the at least portion of the mask until a desired thickness of the mask is removed.   
     
     
         11 . The process of  claim 10 , wherein the organic material is a photoresist and/or an anti-reflective coating. 
     
     
         12 . The process of  claim 10 , wherein forming the protective layer comprises depositing the protective layer onto the surfaces free of the organic material. 
     
     
         13 . The process of  claim 10 , wherein forming the protective layer comprises passivating the surfaces free of the organic material. 
     
     
         14 . The process of  claim 10 , wherein the nitrogen containing gas comprises N 2 , NH 3 , NO, N 2 O 3 , N 2 O, nitrogen containing hydrocarbons, or mixtures thereof. 
     
     
         15 . The process of  claim 10 , wherein the inert gas is selected from a group consisting of helium, argon, nitrogen, krypton xenon, and neon 
     
     
         16 . The process of  claim 10 , wherein the carbon containing gas comprises CO 2 , CH 4 , HCN, C 2 O, CO or mixtures thereof. 
     
     
         17 . The process of  claim 10 , wherein the plasma mediated stripping process comprises exposing the substrate to an oxidizing plasma or a reducing plasma. 
     
     
         18 . A plasma processing system for processing an inorganic workpiece substrate having organic material residing thereon by removing the organic material while leaving the inorganic substrate substantially unaltered, comprising:
 a process chamber for processing the workpiece placed therein;   a plasma source for delivering excited state gas into said process chamber to produce a reactive environment therein;   a gas delivery system, including a plurality of gas valves, for selectively delivering at least one gas from a gas supply to said plasma source;   a power generator assembly for powering the plasma source to excite the gas delivered by said gas delivery system; and   a control system for selectively activating said gas valves of said gas delivery system so as to provide at least a first selected gas for at least a first selected time interval for forming a protective layer on the substrate, and at least a second selected gas for at least a second selected time interval for removing the organic material residing on the workpiece substrate.   
     
     
         19 . The plasma processing system of  claim 18 , further comprising a UV light source for exposing the workpiece substrate to UV radiation for at least a portion of the first selected time interval for forming the protective layer on the substrate. 
     
     
         20 . The plasma processing system of  claim 19 , wherein the gas supply includes a plurality of gases, including reactive gases and/or inert gases, and further wherein:
 the control system is operative such that the first selected gas provided during the first selected time interval is a reactive gas; and   the control system is further operative such that the second selected gas provided during the second selected time interval is a reactive gas.   
     
     
         21 . The plasma processing system of  claim 19 , wherein the gas supply includes a plurality of gases, including reactive gases and/or inert gases, and further wherein:
 the control system is operative such that the first selected gas provided during the first selected time interval is an inert gas; and   the control system is further operative such that the second selected gas provided during the second selected time interval is a reactive gas.   
     
     
         22 . The plasma processing system of  claim 18 , wherein the protective layer includes a passivation layer formed in a surface layer of the workpiece substrate. 
     
     
         23 . The plasma processing system of  claim 18 , wherein the protective layer is a deposition layer formed on a surface layer of the workpiece substrate. 
     
     
         24 . The plasma processing system of  claim 18 , wherein said valves of said gas delivery system include a mass flow controller for measuring and controlling a flow of a selected gas delivered through the gas delivery system. 
     
     
         25 . The plasma processing system of  claim 24 , wherein said mass flow controllers are capable of switching between an open state and a closed state in less than one second. 
     
     
         26 . The plasma processing system of  claim 18 , wherein said process chamber has a volume of less than 20 liters. 
     
     
         27 . The plasma processing system of  claim 18 , wherein said process chamber and gas delivery system are operative to provide a gas flow rate of at least 1 slm. 
     
     
         28 . The plasma processing system of  claim 18 , wherein said chamber has a volume and the gas delivery system is configured to provide a gas flow such that gas flow≧chamber volume÷2 seconds.