Japanese maker Nikon Corporation has introduced the new NSR-S630D ArF immersion scanner for patterning of IC chips at 10nm and below.
This news could be very important in an industry which is now moving from 14nm patterning to 10nm patterning and below in the next few years. Intel is already working on 10nm for its next generation of chips and beginning of production of 10nm IC components is scheduled for 2015.
Due to the increasing process complexities needed to transfer patterns of few tens of nanometers from the mask to the wafer, the industry has been exploring various options in the last two decades as it was widely believed until a few years ago that traditional stepper lithography would run out of gas around 90nm. The most prominent of such technologies is without doubt EUV, and most of the top-tier IC makers have invested billions in this technology. EUV technology is not employing a 193nm wavelength, but instead uses a much thinner 13.5-nm extreme ultra-violet light-source therefore allowing the patterning of much finer lines.
But while EUV has been plagued by numerous delays and it is now expected to reach maturity for high-volume production in a couple of years at the earliest, the life of traditional UV lithography has been extended thanks to numerous tweaks and fixes like multiple patterning and immersion which have helped the industry move from 90nm to the current generation of IC devices patterning at 14nm.
The new S630D stepper is part of the advanced Streamlign platform and delivers revolutionary solutions in order to extend the life of 193 nm immersion lithography until the 7nm node or possibly even up to the 5nm node, which is widely believed to be the end of traditional transistor scaling and the beginning of quantum-related nanotechnology.
Differently from EUV technology, where engineers are struggling to reach an output of 100 wafers/hours, Nikon has qualified their new scanner for HVM (high volume manufacturing) production at a whopping 250 wafer-per-hour efficiency. The new scanner is now able to achieve a resolution with is more than an order of magnitude finer than the wavelength of the laser used thanks to the improvements in reticle positioning accuracy and in thermal stress management. The new S630D is now able to reach a previously-unheard-of mix-and-match overlay (MMO) lower than 2.5nm and this means that the scanner is now able to meet most stringent requirements needed for multiple patterning with immersion.
The reason why such overlay requirements are so stringent is due to the fact that patterning such fine lines with a 193nm is like drawing a fine sketch using a broad brush. In order to achieve this, it is necessary to split all the patterning process into two, three or more masks and dedicate each single mask to a part of the whole patterning process. However, splitting the patterning process into multiple parts requires a strict overlay in order to avoid positioning errors between two subsequent exposures.
Hamid Zarringhalam, Nikon Precision Executive Vice President stated that his company is working hard to satisfy the device makers increasingly high demands for high-throughput production of IC devices at increasingly finer dimensions. Mr. Zharringalam believes that the key aspect of the new scanner offered by Nikon is the extremely accurate overlay control which reaches below 2.5nm and allows to bring multiple patterning to sub 10-nm patterning.
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