July 7, 2003 – The Tokyo-based Association of Super-Advanced Electronics Technologies (ASET), a government-funded electronics research cooperative, says it has developed a way to fabricate high-performance masks for extreme ultraviolet (EUV) lithography.

The masks are constructed from multiple alternating layers of molybdenum and silicon built up on a glass sheet; light is then reflected off the sheet, through the masks and onto the wafer to define circuit patterns down to 45nm.

ASET says that using a method called helicon sputtering, it can produce masks with a defect rate of less than one-tenth the usual number per unit-area of exposure.