Chamber stability monitoring using an integrated metrology tool
A method and apparatus for monitoring the stability of a substrate processing chamber and for adjusting the process recipe. Thickness and CD measurement data are collected before wafer processing and after wafer processing by an integrated or an in-situ metrology tool to monitor process chamber stability and to adjust the process recipe. The real time chamber stability monitoring enabled by the integrated metrology tool reduces the risk and cost of wafer mis-processing. The real time process recipe adjustment allows tightening of the process recipe. Process development cycle can also be reduced by the method and apparatus.
1. A method of monitoring a process performed by a etch chamber, comprising:
collecting pre-process measurement data prior to substrate processing using an integrated metrology tool;
processing the substrate in the etch chamber;
recording a total processing time;
collecting post-process measurement data after substrate processing using the integrated metrology tool, wherein the pre-process measurement data and post-process measurement data include both thickness measurement and critical dimension information;
calculating a process rate by subtracting post-process measurement data from pre-process measurement data and dividing the result by the total processing time;
computing a process rate trend;
comparing the process rate trend to a limit level;
signaling detection of a performance drift when the process rate trend exceeds the limit level;
examining a pre-etch critical dimension information; and
excluding a contribution of the critical dimension of a feature as a cause of the process drift, if the pre-etch critical dimension information is within a pre-defined critical dimension specification.
2. The method of claim 1 wherein each movement of the substrate is performed within a vacuum.
3. The method of claim 1 wherein the integrated metrology tool performs at least one of scatterometry and reflectometry to produce pre-process and post-process measurement data.
4. The method of claim 1 , further comprising:
adjusting, in real time, a process recipe used by the etch chamber to process the substrate based on the pre-process measurement data and a process rate.
5. The method of claim 4 , wherein the process rate trend is an etch rate trend.
6. The method of claim 1 , wherein the integrated metrology tool is an in-situ metrology tool.