Voltage Contrast Enhancement for Gate Leak Failure Detected by Electron Beam Inspection

We studied the VC (voltage contrast) enhancement technique of the FA (failure analysis) tool. We found a gate leak VC dependency on the relative angle between the beam scan direction and gate electrode direction. A simplified RC model can explain this phenomenon qualitatively. With the help of this VC enhancement technique of the FA tool, we could tune the EBI recipe in appropriate sensitivity. As a result, correct EBI evaluation results of countermeasure experiments led us to a solution within a shorter period of time.