Wafer produced by method of quality control for chemical vapor deposition

Abstract

A residual gas analyzer can be used as a deposition rate monitor. A deposition rate monitor is based on the detection of growth precursors and reaction byproducts of the thin film growth in deposition equipment such as chemical vapor deposition (CVD) systems. The growth precursors and byproducts are identified and quantified by using a residual gas analyzer (RGA). The ion current from gas species associated with the growth rate is then empirically correlated with the thickness of the film. The specific chemical species detected by the RGA is unique to the material that is deposited and to the technique in which the material is deposited.

What is claimed is:  
     
         1 . A method of correlating resulting gaseous environments in a chemical vapor deposition (CVD) reactor with physical properties of deposited films, comprising the steps of: 
 depositing a film in the CVD reactor at a selected temperature utilizing a selected input gaseous mixture;    measuring a resulting gaseous environment in the CVD reactor as a result of the depositing step;    measuring a physical property of the deposited film; and    correlating one or more gas species in said resulting gaseous environment, said selected temperature, and said selected input gaseous mixture with said physical property to identify a relationship therebetween.    
     
     
         2 . The method of    claim 1   , wherein: 
 said selected temperature is between approximately 430 and 470 degrees Celsius; and    said selected input gaseous mixture includes a helium carrier gas flow of between approximately 75 and 375 sccm.    
     
     
         3 . The method of    claim 1   , wherein said depositing step comprises: 
 depositing a film of titanium nitride (TiN) at said selected temperature and with said selected input gaseous mixture.    
     
     
         4 . The method of    claim 1   , wherein said step of measuring a resulting gaseous environment comprises: 
 identifying a plurality of possible byproducts each having a corresponding mass spectrum;    after said depositing step, ionizing a portion of said resulting gaseous environment to result in an actual mass spectrum; and    comparing said actual mass spectrum and each said corresponding mass spectrum to obtain a plurality of gas species ratios corresponding to said plurality of possible byproducts.    
     
     
         5 . The method of    claim 1   , wherein said step of measuring a resulting gaseous environment comprises: 
 selecting a gas species having a corresponding appearance energy;    generating an ionization energy corresponding to said appearance energy, as a result of the depositing step; and    detecting said gas species.    
     
     
         6 . The method of    claim 1   , wherein said step of measuring a resulting gaseous environment comprises: 
 measuring the intensities of at least one of the peaks at 15, 41, 42, 44, 54, 67, and 106 atomic mass units in said resulting gaseous environment.    
     
     
         7 . The method of    claim 1   , wherein said step of measuring a physical property comprises: 
 measuring a thickness of said film.    
     
     
         8 . The method of    claim 1   , wherein said step of measuring a physical property comprises: 
 measuring a sheet resistance of said film.    
     
     
         9 . The method of    claim 1   , wherein said correlating step comprises: 
 identifying a plurality of gas species resulting from said depositing step; and    determining said one or more gas species from said plurality of gas species based on a correlation to said physical property for said selected temperature and said selected input gaseous mixture.    
     
     
         10 . The method of    claim 1   , further comprising the steps of: 
 before said depositing step, inserting into the chemical vapor deposition reactor a wafer on which said film is to be deposited; and    before said step of measuring said physical property, removing said wafer from said chemical vapor deposition reactor.    
     
     
         11 . The method of    claim 1   , further comprising the step of: 
 successively performing a plurality of times said steps of selecting, depositing, measuring said resulting gaseous environment, measuring said physical property, and correlating,    wherein said step of successively performing results in a correlation table between said plurality of temperatures, said plurality of input gaseous mixtures, a plurality of physical properties, and a plurality of gas species.    
     
     
         12 . The method of    claim 1   , wherein said step of correlating comprises: 
 correlating one or more gas species ratios in said resulting gaseous environment, said selected temperature, and said selected input gaseous mixture with said physical property to identify a relationship therebetween.    
     
     
         13 . A method of monitoring depositions of films in a chemical vapor deposition (CVD) reactor, comprising the steps of: 
 providing a correlation table between a plurality of temperatures, a plurality of input gaseous mixtures, a plurality of physical properties of deposited films, and a plurality of resulting gaseous environments;    designating a physical property of a film to be deposited;    referencing with said correlation table a selected one of said plurality of temperatures, a selected one of said plurality of input gaseous mixtures, and a range of one or more gas species of said plurality of resulting gaseous environments in accordance with said designated physical property;    depositing said film in the CVD reactor at said selected temperature utilizing said selected input gaseous mixture;    measuring one or more gas species in a resulting gaseous environment in the CVD reactor that results from said depositing step;    comparing the measured one or more gas species in said resulting gaseous environment and said range of one or more gas species; and    generating a comparison result in accordance with said comparing step, wherein said comparison result indicates a difference between said designated physical property and an actual physical property resulting from said depositing step.    
     
     
         14 . A wafer including said deposited film monitored by the process of    claim 13   .  
     
     
         15 . The method of    claim 13   , wherein: 
 said physical property is a thickness of said film.    
     
     
         16 . A wafer including said deposited film monitored by the process of    claim 15   .  
     
     
         17 . The method of    claim 13   , wherein: 
 said physical property is a sheet resistance of said film.    
     
     
         18 . A wafer including said deposited film monitored by the process of    claim 17   .  
     
     
         19 . The method of    claim 13   , further comprising the step of: 
 before said depositing step, measuring one or more gas species in a pre-deposition gaseous environment.    
     
     
         20 . A wafer including said deposited film monitored by the process of    claim 19   .  
     
     
         21 . The method of    claim 13   , where in: 
 said one or more gas species have molecular masses of at least one of 15, 41, 42, 44, 54, 67, and 106 atomic mass units.    
     
     
         22 . A wafer including said deposited film monitored by the process of    claim 21   .  
     
     
         23 . The method of    claim 13   , wherein said depositing step comprises: 
 depositing said film of titanium nitride (TiN) at said selected temperature and with said selected input gaseous mixture.    
     
     
         24 . A wafer including said deposited film monitored by the process of    claim 23   .  
     
     
         25 . The method of    claim 13   , wherein said measuring step comprises: 
 measuring an ion current of said one or more gas species in said resulting gaseous environment as said result of said depositing step.    
     
     
         26 . A wafer including said deposited film monitored by the process of    claim 25   .  
     
     
         27 . The method of    claim 13   , wherein said comparing step comprises: 
 determining a value of a first gas species of said one or more gas species; and    comparing said value and said range for said first gas species.    
     
     
         28 . A wafer including said deposited film monitored by the process of    claim 27   .  
     
     
         29 . The method of    claim 13   , wherein said steps of referencing, measuring, and comparing comprise: 
 referencing with said correlation table said selected temperature, said selected input gaseous mixture, and a range of one or more gas species ratios of said plurality of resulting gaseous environments in accordance with said designated physical property;    measuring one or more gas species ratios in a resulting gaseous environment as said result of said step of depositing; and    comparing said one or more gas species ratios in said resulting gaseous environment and said range of one or more gas species ratios.    
     
     
         30 . A wafer including said deposited film monitored by the process of    claim 29   .  
     
     
         31 . The method of    claim 13   , further comprising the steps of: 
 successively performing a plurality of times said steps of depositing, measuring, and comparing; and    generating a plurality of overall comparison results in accordance with said plural steps of comparing, wherein said plurality of overall comparison results provide statistical information on the depositions performed in said plural steps of depositing.    
     
     
         32 . A wafer including said deposited film monitored by the process of    claim 31   .