System and method for resolving photoemission from semiconductor devices

A system for resolving light collected from device under test (DUT), comprising:

• a first input receiving optical signal correlating to the light collected from the DUT;
• a second input receiving CAD layout of the DUT;
• a spread function engine generating a spread function for each state combination of plurality of transistors selected from the CAD layout;
• a comparator receiving the optical signal and each of the spread functions and providing a plurality of error signals, each error signal corresponding to difference between the optical signal and the spread function of one state combination;
• a decision engine receiving the error signals of the plurality of state combinations and outputting a decision signal indicating the most probable state combination.

An optical tester for testing a semiconductor device under test (DUT), comprising:

• a collection optics for collecting light from the DUT;
• a sensor for sensing the light from the collection optics and generating a collection signal;
• an input for receiving CAD layout of the DUT;
• a spread function generator generating spread function for a plurality of transistors selected from the CAD layout;
• a comparator comparing the spread function to the collection signal and outputting an error signal.