Patent ID: 7482178

Claim:
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.