Negative Mode E-Beam Inspection of the Contact Layer

Contact CMP is one of the most popular layers for application of e-beam inspection. Using voltage contrast, contact opens and shorts may uniquely be detected. Generally positive surface charging (positive mode) is used, but negative surface charging (negative mode) provides a number of noteworthy advantages, including throughput, which are highlighted in this paper. Usually, adjustment of the landing energy or electric field is used to shift a wafer image into negative mode. This paper introduces and demonstrates a new control knob, beam density.