BMD impact on silicon fin defect at TSV bottom

A new type of through-silicon via (TSV) defect, silicon fin defect, which was found after the TSV deep-reactive-ion-etching process at the TSV bottom is reported. These defects are considered killer TSV defects that may cause process or mechanical failures and have to be eliminated. A scanning electron microscope automatic process inspection approach, which is non-destructive and proven to be effective, has been established to image the fin defects at the bottom of the trench. A possible root cause of this defect is also explored. Both simulation and benchmarking test results indicate that bulk micro defects (BMDs) in the silicon substrate could serve as a micro-mask during etching and result in silicon fin defects.