In the competitive semiconductor marketplace, rapid development of new semiconductor designs and shrinking design rules drive the need for continuous yield enhancement. As design rules shrink, the critical defect size becomes smaller and the identification of defects becomes more challenging. Correct compositional identification of wafer defects has become vital for optimizing tool performance and can have significant financial impact.
Defects are usually first discovered in an optical detect mapping tool, which typically provides location and sizing information for the defects (Fig. 1a). A map is generated that shows the location of the defects on the wafer (Fig. 1b). Individual defects are then located using the coordinates provided by the particle scanner and an SEM image of the defect is obtained (Fig. 1c). Finally, a compositional analysis is performed (Fig. 1d).