Scattered signal collection using strobed technique

A scatterometry system for ascertaining in-situ a thin film thickness in a process chamber having a rotating substrate undergoing processing therein, comprising:

• a registration feature associated with the substrate, wherein a position of the registration feature is related to a position of a periodic analysis structure on the substrate;
• a registration feature detection system operable to determine when the registration feature is in a predetermined position, and to provide an indication thereof;
• a scatterometry data collection system operable to collect scattered radiation associated with the periodic analysis structure based on the indication from the registration feature detection system and generate scatterometry data associated therewith;
• and
• a processor operable to determine the thin film thickness based on the scatterometry data.

A method of controlling a thin film formation on a substrate, comprising:

• employing a thin film formation process to form a thin film on a substrate based on one or more thin film formation process parameters;
• moving the substrate during the thin film formation process;
• determining a position of the substrate during the thin film formation process;
• obtaining scatterometry data from a pattern on the substrate based on the determined position of the substrate;
• and
• providing feedback control over the thin film formation process based on the scatterometry data, wherein the feedback control controls at least one of the one or more thin film formation process parameters.