GTC 2010 According to AMD-spinoff GlobalFoundries, chip-baking is about to hit a wall — but they're ready for it. They also claim that their way of handling the latest advance in chip materials is superior to that used by Intel and soon to be introduced by their ginormous competitor, TSMC.
On Wednesday at its first annual Global Technology Conference in Santa Clara, California, GlobalFoundries shared its plans with a few hundred of the world's chip designers, and spent the day explaining why GlobalFoundries is the chip-baker that they should trust with their futures.
The wall that chipmakers are rushing toward is the fact that wavelengths of light are too big for current lithographic techniques to continue to scale down effectively to be able to create tinier and tinier transitors. That's an oversimplification, of course, but you get the idea.
Gregg Bartlett, GlobalFoundries SVP for technology and R&D, told the conference attendees that the current high-end technique — known as 193nm immersion lithography and introduced at the 45nm node — is reaching its limit. "Today we sit on what is effectively the end of evolutionary changes for wavelength scaling," he said.
In a nutshell, there are two types of immersion lithography: single and double-patterning technology. Double patterning allows for smaller silicon features, but its notoriously complex and expensive. "Double-pattern immersion lithography will [be used] down to and including the 20nm technology node," Bartlett said, but due to significant complexity and cost challenges, the cost involved "effectively lowers the bar for alternate lithography schemes."
According to Bartlett, there are a few alternate schemes from which to choose:. "We do know that there is disruptive innovation that is now necessary to continue fueling the technology roadmap going forward. And there are multiple candidates out there such as multi-e-beam direct write, extreme ultraviolet lithography, and even nano-imprint lithography."
GlobalFoundries is betting on extreme ultraviolet lithography, better known among chip-bakers as EUV. "We really do see EUV squarely in our technology roadmap," Bartlett said.
But it's not a simple matter of swapping those double-pattern systems out of fabs and replacing them with EUV gear. "EUV is not without its share of challenges," Bartlett said, citing defect-free masks as one of the most significant problems, along with line-edge roughness at fine resolutions and EUV's hunger for power.
Bartlett noted that mask and line-edge improvements are underway, but that despite "several orders of magnitude improvement over the last decade," source power and throughput aren't yet at what he referred to as "the crossover point." He did, however, express satisfaction at the rate of progress.
And then there's that all-encompassing bugaboo, total cost of ownership. The fixed costs of a EUV installation are still more than double that of single-pattern immersion lithography, and slightly more than that of double-pattern immersion. It's in other areas — namely chemical and reticle costs, plus exposure expenses — where EUV is more cost-effective than double-pattern, according to Bartlett.
But moving to EUV has the distinct advantage of not requiring double patterning. "Because you can single-pattern [EUV]," Bartlett contends, "it actually offers a cost-reduction opportunity."
Over the past decade, he said, GlobalFoundries (as an arm of AMD) has made significant strides in EUV development. In 2008, for example, they accomplished their first full-field EUV patterning on a 45nm test chip, they've shipped more than 60 EUV masks from their mask-manufacturing facilities in Dresden, Germany, and the company "continues to lead" in solving the line-edge roughness problem.
Plans are now in place for GlobalFoundries to establish its first EUV-based production facility in the first half of 2012 at its Fab 8 facility in Saratoga County, New York, currently under construction and designed to produce 300mm wafers using 28nm and smaller process technologies. Bartlett said that volume production of EUV-etched wafers is planned for 2014 or 2015.