Analysis of silicide process defects by non-contact electron-beam charging

Electron beam charging without any conventional electrical measurements has been used to understand gate electrode leakage currents in a silicide process. Using this technique, it was determined that the leakage is caused by single defects which are small compared to the typical circuit dimensions, which occur on the gate perimeter, and are randomly distributed. Combined with one additional process step, it was determined that the leakage is not due to silicide bridging, but rather to a gate oxide overetch. The measurement has been instituted as an inline process monitor to screen for silicide leakage defects. >