A 104 watt EUV light source was produced which would enable 60 wafers per hour. However pressure remains for a EUV source capable of 250-watts at intermediate focus. Indeed it is possible that for the NXE3300 production machines, due in 2012, the LPP (laser produced plasma) source could be replaced by a discharge-produced plasma (DPP) source, Ronse said. “The decision is not made yet,” he said.
What if EUV is Delayed Again? Reliability of Moore’s Law at Risk
What if the source energy cannot be raised or the mask inspection tools cannot find the yield-busting defects, or the resists fail to perform. Does that mean that 193-nm wavelength optical lithography can fill the gap?
Not easily, although it is being considered as a fall-back position, Ronse said. But overlay specifications become tighter so chip makers would likely need new machines and they might require quadruple patterning to squeeze extra resolution from the 193-nm wavelength. That would in turn increase the dwell time on the machine and harm productivity making the machines substantially less capital efficient.
It would seem more likely that Moore’s Law and the ITRS would incur the delay in moving to 16-nm that would finally mark the end of steady scaling. In fact IMEC’s Van den Hove made the point in remarks ahead of the IMEC Technology Forum that lithography-enabled scaling in 2-d is likely to slow down while being compensated for by integrated complexity in the third dimension.
Ronse was able to report continued progress with mask and wafer inspection, with resist materials with improving line-edge roughness down to below 4-nm, albeit constrained by resolution. IMEC is contributing its data to the EUV Mask Inspection Partnership formed by Sematech and being funded by the six leading semiconductor manufacturers with an interest in EUV. And in terms of circuit complexity IMEC has made a second generation 22-nm SRAM cell with an area of 0.079 square meters and improved yield. The next circuit to be built is a 16-nm SRAM.
IMEC held the official opening of its 300-mm expansion on Tuesday (June 8) and the NXE3100 pre-production tool is now expected to arrive late in 2010, one of the first six that ASML is shipping. The NXE3100 will have a laser produced plasma (LPP) source from Cymer capable of 100 watts at the intermediate focus which be bright enough to support a throughput of 60 wafers per hour. That’s not enough for commercial production which is demanding 150 wafers per hour, said Ronse.