Microelectronics and semiconductor wafer manufacturing are among the fastest evolving technology industries today. Wafer sizes typically are 200 mm to 300 mm while critical dimensions are shrinking to 0.09 μm and smaller. As the size of discrete devices continues to be reduced while device density increases, the need for fast, accurate, flexible metrology and inspection tools in the microelectronics industry grows.

Back in the early 1980's, semiconductor inspection was performed primarily by brightfield optical microscopes and with automated detection tools. The adaptation of automated detection tools led to the systematic control of increasingly smaller defects. The smallest detectable defect using these automated tools fell to below the 0.30-micron mark during the 1990's.