公开(公告)号：FR2803915A1

公开(公告)日：2001-07-20

申请号：FR0100299

申请日：2001-01-11

Applicant: SCHLUMBERGER TECHNOLOGIES INC

Inventor： KASAPI STEVEN A ,  TSAO CHUN CHENG ,  SOMANI SEEMA

IPC: G01R31/26 ,  G01N21/00 ,  G01N21/01 ,  G01R1/06 ,  G01R15/24 ,  G01R31/302 ,  G01R31/308 ,  H01L21/66

Abstract: A laser beam is used to probe an integrated circuit device under test. A single laser provides a single laser pulse which is divided into two pulses, both of which are incident upon the device under test. After the two pulses interact with the device under test, the two pulses are separated and detected by two photo detectors. The electrical signals output by the photo detectors are then subtracted, which cancels out any common mode noise induced on both pulses including noise due to mechanical vibration of the device under test and also any noise from the laser. The difference signal can be used to reproduce a time varying signal in the device under test.