Method and system for monitoring an etch process

Abstract

A method and apparatus for monitoring an etch process. The etch process may be monitored using measurement information (e.g., critical dimensions (CD), layer thickness, and the like) provided ex-situ with respect to the etch process in combination with in-situ monitoring (e.g., spectroscopy, interferometry, scatterometry, reflectometry, and the like) performed during the etch process. The ex-situ measurement information in combination with the in-situ monitoring may be used to monitor for example, an endpoint of an etch process, an etch depth profile of a feature formed on a substrate, fault detection of an integrated circuit manufacturing process, and the like.

1 . A system for monitoring an etch process, comprising:
 at least one reactor to perform an etch process;   at least one metrology module to provide pre-etch measurement information to the at least one etch reactor; and   at least one substrate robot, wherein the at least one reactor comprises an etch process measuring module for monitoring an etch process endpoint in the etch reactor.   
     
     
         2 . The system of  claim 1  wherein the at least one etch reactor is a plasma reactor. 
     
     
         3 . The system of  claim 1  wherein the at least one metrology module uses a non-destructive optical measuring technique. 
     
     
         4 . The system of  claim 1  wherein the etch process measuring tool uses an interferometric measuring technique. 
     
     
         5 . The system of  claim 1  wherein the etch process measuring tool further comprises:
 a source of a radiation to illuminate a region on the substrate; and 
 an interferometer. 
 
     
     
         6 . The system of  claim 1  wherein the source of radiation provides radiation substantially perpendicular to the substrate. 
     
     
         7 . The system of  claim 1  wherein the source of radiation provides radiation at wavelengths in a range from about 200 to 800 nm. 
     
     
         8 . The system of  claim 5  wherein the source of radiation modulates an intensity of the radiation at a frequency of about 10 Hz. 
     
     
         9 . An in-situ metrology tool, comprising:
 at least one plasma reactor to perform wafer processing;   at least one measurement module, coupled to the at least plasma reactor, for measuring at least one of a thickness of a layer on a substrate and a critical dimension; and   at least one plasma state monitoring module, coupled to the at least one plasma reactor, for monitoring a plasma state within the at least one plasma reactor.   
     
     
         10 . The tool of  claim 9  wherein the thickness measurement module uses an interferometric measuring technique. 
     
     
         11 . The tool of  claim 9  wherein the critical dimension measurement module uses a non-destructive optical measuring technique. 
     
     
         12 . The tool of  claim 9  wherein the plasma state monitoring module usages an optical electromagnetic emission measuring technique. 
     
     
         13 . The tool of  claim 9  wherein the plasma reactor is a plasma etch reactor. 
     
     
         14 . A method of processing data collected by an in-situ metrology tool of a semiconductor wafer processing system, comprising:
 examining data representing signal intensity versus time as collected by the in-situ metrology tool; and   selecting, based on the data, a time window for performing a Discrete Fourier Transformation upon at least one portion of the data.   
     
     
         15 . The method of  claim 14 , further comprising:
 if the data representing signal intensity versus time indicate decreasing peak to peak periods, reduce the time window; and   if the data representing signal intensity versus time data indicate increasing peak to peak periods, increase the time window.