Self contained sensing apparatus and system

A self contained sensing apparatus for sensing a parameter within the interior of a functioning semiconductor wafer processing chamber during the processing of semiconductor wafers, the chamber having a gate opening and a robot arm, the sensing apparatus comprising:

• a housing establishing an interior compartment, the housing having a maximum thickness which is less than the size of the gate opening so that the housing may be inserted into the chamber through the gate opening, the housing including a window extending through a principal housing surface;
• a sensor within the housing and generally aligned with the window for sensing a parameter within the interior of the chamber during semiconductor wafer processing;
• and
• a transmitter within the housing coupled with the sensor for receiving signals representative of the sensed parameter and transmitting the signals out of the housing for analysis.