Patent ID: 8524099

Claim:
A method for optical access to process events occurring in a process chamber, the method comprising the operations of: defining a gas and optical access path having an axial orientation from a substrate when present in the process chamber and an optical access window of the process chamber, the gas and optical access path being configured to simultaneously carry gas and transmit an optical signal from the process chamber to an analysis tool that operates in response to the signal having a desired signal-to-noise ratio (SNR) for process analysis, the defined path configuration being capable of transmitting the desired SNR that is high enough for the tool to accurately indicate the process analysis; and dividing the gas and optical access path having the access to the optical access window into a plurality of separate gas and optical access apertures between the process chamber and the analysis tool, the dividing provides one or more separators that define the apertures and are arranged along the axial orientation, the apertures collectively maintain the desired SNR of the optical signal transmitted to the tool.