Patent ID: 7616312

Claim:
A system for testing an integrated circuit microchip including a plurality of devices using laser probing, comprising: a laser source providing a laser beam; a beam optics wherein the beam optics comprises a Faraday rotator that rotates a polarization direction of an incident beam to define a rotated beam, the rotated beam comprising two mutually orthogonally polarized components that are aligned respectively with a length direction and a width direction of a device located at a selected spot, and a variable retarder having a fast axis and a slow axis, the fast and slow axes aligned with respective ones of the two mutually orthogonally polarized components, the variable retarder phase shifting one beam component relative to the other beam component, and an objective lens to direct the beam to the selected spot; a first photodetector receiving reflected laser light that is reflected from said microchip and providing an electrical signal; collection electronics receiving the electrical signal from said first photodetector and providing an output signal; and an analysis system receiving and analyzing said output signal.