ASML is one of the world’s leading manufacturers of chip-making equipment. Headquartered in Veldhoven, the Netherlands, ASML employs more than 14,000 people.
The YieldStar S-250D is a standalone metrology tool which allows measurement of on-product overlay and focus using diffraction based overlay (uDBO) and diffraction based focus (DBF) techniques as well as the optional capability to measure ADI CD.
Overlay (uDBO, 10x10 um2 targets)
The YieldStar S-250D enables and supports the following applications:
On-product overlay measurements for monitoring and APC (in conjunction with Overlay Optimizer), using 10x10 um and 16 x16 um targets in-die (uDBO) or 30x60 um targets in scribelane (STOV)
On-product focus measurements for monitoring and APC (in conjunction with Imaging Optimizer)
On-product CD ADI measurement is an option for inline measurement of CD
YieldStar S-250D provides increased sampling compared to the S-200C, being 30% faster per uDBO measurement.
Diffraction based techniques are, by design, more robust against process variations and marker damage on product wafers, especially at the edge of the wafer. This gives very precise on-product overlay and focus measurements per field needed to calculate more accurate corrections to be applied on the scanners.
The S-250D has 30% better TMU compared to the S-200C which supports more precise measurements resulting in better corrections and better on-product overlay and focus performance of the scanner, supporting 2014-15 customer roadmaps.
The correlation of DBO measurements to real device overlay is better than that of IBO measurements which is of particular value at tighter on-product overlay requirements.