Method to chemically remove metal impurities from polycide gate sidewalls

Abstract

An embodiment includes a process of forming a gate stack that acts to resist the redeposition to the semiconductive substrate of mobilized metal such as from a metal gate electrode. An embodiment also relates to a system that achieves the process. An embodiment also relates to a gate stack structure that provides a composition that resists the redeposition of metal during processing and field use.

1 . A system comprising: 
 a semiconductor structure comprising a substrate;    a metal film disposed over the substrate;    wherein the metal film is selected from Al, Cu, Ag, Au, Ti, Zr, Hf, Ni, Co, Pd, Pt, V, Ta, Nb, Cr, Mo, W, Sc, Yt, La, Ce, Rh, Os, Ir, and combinations thereof;    a processing tool comprising a chamber; and    at least one getterer composition selected from a getterer comprising a halogen-containing composition, wherein the at least one getterer composition comprises a thermodynamic or kinetic advantage over the semiconductor structure for combining with the metal film.    
   
   
       2 . The system according to  claim 1 , wherein the getterer composition comprises a fluorine-containing composition.  
   
   
       3 . The system according to  claim 1 , wherein the halogen-containing composition comprises from 1% halogen to 20% halogen.  
   
   
       4 . The system according to  claim 1 , wherein the getterer comprises a fluorine-containing gas composition in a volumetric concentration range from 0.1% to 10%.  
   
   
       5 . The system according to  claim 4 , wherein the getterer comprises NF 3  in a volumetric concentration range from about 0.1% to about 10%.  
   
   
       6 . The system according to  claim 1 , wherein the getterer comprises a halogen selected from F, Cl, Br, I, and combinations thereof.  
   
   
       7 . A system comprising: 
 a semiconductor structure comprising a substrate;    a metal film disposed over the substrate; and    at least one getterer composition disposed in proximity with the metal film.    
   
   
       8 . The system of  claim 7 , wherein the at least one getterer composition is selected from a getterer gas and a getterer solid.  
   
   
       9 . The system of  claim 7 , wherein the getterer composition is selected to provide a thermodynamic or kinetic advantage over the semiconductor structure for combining with the metal film during a thermal cycle.  
   
   
       10 . The system of  claim 7 , wherein the getterer composition comprises a halogen-containing composition.  
   
   
       11 . The system of  claim 10 , wherein the halogen containing composition includes fluorine.  
   
   
       12 . The system of  claim 11 , wherein the halogen containing composition includes NF 3  in a volumetric concentration range from 0.1% to 10%.  
   
   
       13 . The system of  claim 7 , wherein the metal film is selected from Al, Cu, Ag, Au, Ti, Zr, Hf, Ni, Co, Pd, Pt, V, Ta, Nb, Cr, Mo, W, Sc, Yt, La, Ce, Rh, Os, Ir, and combinations thereof;  
   
   
       14 . A system comprising: 
 a gate dielectric layer disposed over a semiconductor substrate;    a doped polysilicon electrode disposed over the gate dielectric layer;    a tungsten nitride barrier layer disposed over the polysilicon electrode;    a metal film disposed over the tungsten nitride barrier layer, wherein the metal film is selected from Al, Cu, Ag, Au, Ti, Zr, Hf, Ni, Co, Pd, Pt, V, Ta, Nb, Cr, Mo, W, Sc, Yt, La, Ce, Rh, Os, Ir, and combinations thereof;    a processing tool comprising at least one chamber; and    at least one composition selected from a gas and a solid, wherein the at least one composition comprises a thermodynamic or kinetic advantage over the semiconductor substrate for combining with metal from the metal film;    wherein the gas comprises a fluorine-containing composition.    
   
   
       15 . The system according to  claim 14 , wherein the solid comprises a dielectric film disposed over the semiconductor structure, wherein the dielectric film comprises from 0.1% fluorine to 30% fluorine.  
   
   
       16 . The system according to  claim 14 , wherein the gas comprises a fluorine-containing composition in a volumetric concentration range from 0.1% to 10%.  
   
   
       17 . The system according to  claim 14 , wherein the gas comprises NF 3  in a volumetric concentration range from 0.1% to 10%.  
   
   
       18 . A system comprising: 
 a gate dielectric layer disposed over a semiconductor substrate;    a doped polysilicon electrode disposed over the gate dielectric layer;    a barrier layer disposed over the polysilicon electrode;    a metal film disposed over the tungsten nitride barrier layer; and    a getterer composition including a gas composition and a solid composition, wherein the getterer composition comprises a thermodynamic or kinetic advantage over the semiconductor substrate for combining with metal from the metal film.    
   
   
       19 . The system of  claim 18 , wherein the getterer composition comprises a gaseous halogen composition and a halogen containing solid layer disposed upon at least one of the metal film, the barrier layer, the doped polysilicon electrode and the gate dielectric.  
   
   
       20 . The system of  claim 19 , wherein the wherein the gaseous halogen composition comprises a fluorine-containing composition.  
   
   
       21 . The system of  claim 18 , wherein the wherein the metal film is selected from Al, Cu, Ag, Au, Ti, Zr, Hf, Ni, Co, Pd, Pt, V, Ta, Nb, Cr, Mo, W, Sc, Yt, La, Ce, Rh, Os, Ir, and combinations thereof.  
   
   
       22 . The system of  claim 18 , wherein the barrier layer comprises tungsten nitride.  
   
   
       23 . The system of  claim 19 , wherein the halogen containing solid layer comprises a dielectric film disposed over at least one of the polysilicon electrode, the barrier layer and the metal layer, wherein the dielectric film comprises from 0.1% fluorine to 30% fluorine; and wherein the gaseous halogen composition comprises NF 3  in a concentration range from 0.1% to 10%.  
   
   
       24 . The system of  claim 23 , wherein the dielectric film is a nitride layer.  
   
   
       25 . The system of  claim 18 , further including a dielectric cap layer disposed over the metal film, wherein at least one of the barrier layer, the metal film, and the dielectric cap layer include a halogen disposed therein in a range from 0.1% to 30%.  
   
   
       26 . The system of  claim 25 , wherein the halogen comprises fluorine.  
   
   
       27 . The system of  claim 18 , further comprising a sidewall spacer dielectric layer disposed over a sidewall of at least one of the polysilicon electrode, the barrier layer and the metal layer, the sidewall spacer including halogen in a range from 0.1% to 30%.  
   
   
       28 . The system of  claim 27 , further comprising the sidewall spacer dielectric including silicon oxides and silicon nitrides.  
   
   
       29 . The system of  claim 18 , further comprising the polysilicon layer doped with an N type dopant.  
   
   
       30 . The system of  claim 18 , further comprising the barrier layer including at least one material selected from the list including tungsten (W), titanium (Ti), nickel (Ni) and chrome (Cr), nitrides thereof or combinations thereof.