Evaluation of the yield impact of epitaxial defects on advanced semiconductor technologies

Epitaxial defects (e.g., stacking faults, epi-spikes, mounds, hillocks, and pits) can often impact product yields, depending upon the type, size, and location of the defect, as well as the design and yield sensitivity of the respective semiconductor product devices. However, the overall yield impact from epitaxial defects has been difficult to assess since the defect sensitivity, capture rates, and classification for these defects has often been poor on product wafers. In a collaborative study between Intel Corporation and KLA-Tencor Corporation, the SP1^TBI defect inspection system was used to inspect and classify epitaxial wafers for an advanced semiconductor manufacturing process. After completion of the semiconductor processing, the defect kill rates and the yield impact were evaluated using bitmapping analysis. The project results demonstrate that the enhanced defect sensitivity and better capture rate of the SP1^TBI inspection system can provide a significant improvement in the defect inspection capabilities currently being utilized for epitaxial wafers. The SP1^TBI inspection system was also able to successfully classify particles and epitaxial defects using real-time defect classification (RTDC), with greater than 99 percent accuracy. The epitaxial defect levels and the corresponding product yield impact were observed to vary significantly between major silicon wafer suppliers. Consequently, these results can be useful in the development of tighter defect specifications for epitaxial wafers to minimize the resulting yield loss from epitaxial defects