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IBM, GlobalFoundries, and Samsung offer a glimpse of chipmaking's future

The Common Platform Alliance dishes up its hopes and plans

The opportunity doesn't come along every day to get a detailed peek into the future of computing from the people who are building it. Last week, I had just such a chance. I attended the Common Platform Technology Forum, the annual get-together hosted by IBM, Samsung, and GlobalFoundries. These firms are the members of the Common Platform Alliance, a rather unique consortium of chipmakers.

Co-opetition: IBM, Samsung, and GlobalFoundries together
The Alliance member firms banded together over a decade ago in the face of growing challenges in the quest to achieve ever-higher densities in semiconductor production. Somewhat amazingly, this collaborative partnership has held together over time even though the firms involved sometimes compete directly against one another. The collaborators have seen their share of change, of course, most notably as AMD spun off its manufacturing arm into GlobalFoundries and, not long after that, GloFo acquired fellow Alliance member firm Chartered Semiconductor. However, the remaining entities appear to be as committed to working together as ever, with a clear sense that shared, common interests are at stake.

From left to right: Mike Cadigan (IBM), Dr. Gary Patton (IBM),
Dr. K.H. Kim (Samsung), Mike Noonen (GlobalFoundries)

I'm not aware of anything else quite like the Common Platform Alliance in the tech industry. The members include the #2 and #3 foundries in the world, Samsung and GlobalFoundries, firms that manufacture chips for other companies on contract. (TSMC holds the #1 spot.) Odds are that Samsung manufactured the SoC processor driving the smartphone in your pocket, whether it's a Galaxy S3 or an iPhone, and if your PC has an AMD processor inside of it, that chip was likely produced by GlobalFoundries. With the rise of mobile devices and the ballooning costs of building chip factories, the foundry business has grown in market share and importance in recent years. Outside of Intel, many of the most prominent names in the chip business, from AMD and Nvidia to Apple and Qualcomm, are "fabless" semiconductor companies that must rely on outside foundries to produce the silicon they design.

IBM's role in the Alliance is a bit different from the other two firms'. It takes the lead in the research and development of new fabrication techniques, looking ahead a decade or more to determine which avenues might provide the best path to the next reduction in transistor size at near-atomic levels. Much of this research takes place in upstate New York, at the Albany Nanotech Center, where researchers from IBM and academia partner with representatives from the foundries and equipment suppliers to develop upcoming generations of chipmaking tech. GloFo and Samsung then take IBM's basic process technology, modify it to fit their customers' needs, and bring it into high-volume production.

If all of that sounds complicated, that's because it is. This collaborative effort is a mash-up of very large corporations, smaller tools providers, and academics, along with very significant involvement from multiple governments, most notably the State of New York. It is a huge, sprawling enterprise that involves a substantial chunk of the overall semiconductor manufacturing industry. Although Intel typically has been a year or two ahead of the Alliance partners in reaching new, smaller process nodes, the work done by this collaborative effort has contributed in a multitude of ways to the regular drumbeat of Moore's Law, the founding constant of chipmaking that says the number of transistors jammed into a given space will double roughly every two years. This drumbeat has brought us a precipitous downward trend in the cost of computing, along with steady leaps in performance and reductions in power consumption.

Among other benefits, Moore's Law has given us affordable, low-power system-on-a-chip (SoC) processors than have enabled the burgeoning markets for smartphones and tablet computers. Although all three Alliance firms have stakes in other markets, most of the talk at the Tech Forum this year was focused on SoCs for mobile applications, the richest trove of potential customers for the foundries. ARM had a conspicuous presence at the Forum, with an emphasis on its partnership with GloFo, while AMD was conspicuous mostly by its absence.

The presentations at the Forum offered glimpses into several stages of upcoming chip technology, from the now-imminent generation beyond today's 32- and 28-nm silicon to truly wondrous innovations that could be a decade away from making it into real products. The prospects for the continuation of Moore's Law has been a popular source of concern in recent years, but gloom didn't dominate the talk at the Forum. What I saw there was both worrying, because of how much hard work remains to be done, and encouraging, given the wealth of resources being thrown at the problems and the astounding potential of technologies now being explored.

What's next: a new transistor structure at 14 nm
Most immediately, the members of the Common Platform Alliance are working to deliver their next-gen process technologies, whose smallest feature sizes will be 20 and then 14 nm. I should say that each partner is working to deliver its piece of the puzzle, because they tend to diverge when it comes to final implementations. Several years ago, the Alliance articulated a vision of true uniformity and coordination that would allow any product to be manufactured at multiple sites—either at, say, different GloFo fabs in Dresden and New York, or perhaps even at two fabs belonging to different member companies. This year, the Alliance members were frank in admitting that the market instead asked for something else: customization, the ability to tune a solution to a customer's specific needs. As a result, the sort of strict uniformity that would allow fab-to-fab portability is no longer an important goal for the Alliance.

Below is a slide showing GlobalFoundries' process tech roadmap for the next little while. Mike Noonen, EVP of Sales, Marketing, Quality and Design at GlobalFoundries, presented this slide during the summit keynote. GloFo was much more forthcoming than Samsung, generally speaking, about its current status and future plans.

Source: GlobalFoundries

As you can see, the road ahead for GlobalFoundries involves a vastly simplified product offering. The firm offers a host of different process types for different market segments in the 28-nm node, but going forward, each step downward in geometry size includes only one process type. GloFo says each process can be tweaked to meet the needs of different types of devices, but the change is still notable. In the past, for instance, AMD Opterons have been fabricated on a super-high-performance process specifically tailored to achieve the high switching speeds needed for multi-gigahertz operation, using techniques like silicon-on-insulator (SOI). GloFo's 20-nm process, dubbed 20LPM, jettisons SOI in favor of traditional bulk silicon and will serve everything from low-power mobile SoCs to high-performance CPUs. 20LPM is in testing now and is slated to be in production this year.

We are approaching the limits of conventional photolithography, the basis of modern chip fabrication, in which light is directed through a mask and onto a light-sensitive layer of material to etch the patterns that will become circuits. Making the transition to smaller geometries will require some new techniques. Most notably, the 20LPM process employs some double patterning, on the finest metal layers, in order to work around the current resolution limits of photolithography. Double patterning "cheats" by using two different masks, offset slightly, and two light exposures, to achieve a higher effective resolution—a little like interlacing on an old TV screen, only without the resulting flicker.

Since its beginnings, the semiconductor industry has used a mostly flat or "planar" transistor structure that has served it well, but the push to near-atomic-scale devices has led to increases in wasted power, or leakage, that threaten to wipe out the efficiency gains associated with a process shrink. In order to surmount this problem, chipmakers are turning to a transistor structure in which a thin silicon fin protrudes vertically so that it's surrounded by the gate on three sides, offering more conductive surface area—and thus better efficiency. Intel adopted such a transistor structure, which it calls a "tri-gate transistor," for its 22-nm process. Most of the rest of the industry, including the Alliance members, calls this sort of structure a FinFET. GlobalFoundries and the Alliance will use conventional planar transistors for their 20-nm process, and then they'll make the transition to FinFETs at 14 nm.

Although the move to FinFETs is something of a landmark transition, it comes in the form of an incremental step. GloFo's 14XM process will incorporate elements of 20LPM, building on it rather than supplanting it entirely. Like 20LPM, the 14XM process will include some double-patterning, and it will serve a range of devices from low-power mobile to high-performance computing. GloFo expects 14XM to go into production in the first half of 2014. Right now, the roadmap calls for another new process, 10XM, to come online the very next year, in 2015. The Alliance's work at 10 nm employs FinFETs and "second-generation" double-patterning.

One thing we don't know is how GlobalFoundries' highest-profile customer will take advantage of this new process tech. With the changes in leadership at AMD has come a more conservative approach to both roadmap disclosures and process technology transitions. All we know at present is that the next-generation "Kaveri" APU, successor the Trinity and Richland and competitor to Ivy Bridge, is slated for 28-nm production late in 2013. Several of AMD's other products, including the low-power "Temash" APU and the "Sea Islands" graphics chips, will be manufactured by TSMC at 28 nm. We'd expect future Opteron and FX processors to make the transition to 20LPM or 14XM at GlobalFoundries, but neither AMD nor GloFo is willing to talk about specifics.

Rather than discussing its cooperation with AMD, GlobalFoundries chose to highlight its partnerships with various important players in the mobile SoC ecosystem. Chief among them is ARM, whose CPU architectures are licensed by the vast majority of SoC makers. GlobalFoundries announced an expanded partnership with ARM in 2012, and at the Forum, it revealed some of the fruits of that collaboration.

Source: GlobalFoundries

Most notably, GloFo used ARM's Cortex-A9 CPU core as test vehicle for its FinFET-enabled 14XM fab process. Compared to the current super-low-power 28nm process, the Cortex-A9 test chip built on 14XM exhibited considerable improvement, as the slide above illustrates. Those gains can translate into a 62% reduction in power consumption, a 61% increase in operating frequency, or some combination of the two. That's a very healthy generational improvement, suggesting that the move to FinFETs can keep up the Moore's Law-style cadence for at least one more generation.

Other GlobalFoundries partners that Noonen highlighted included Cyclos Semiconductor, whose resonant clocking technology was first deployed in AMD's Piledriver core and contributed to its substantial power savings over the Bulldozer core made on the same process. Cyclos and GloFo are now working together to integrate resonant clocking into the ARM Cortex-A15 at 28 nm, and GlobalFoundries will make this power-saving core available to customers later this year.

Noonen also singled out Adapteva, a small processor startup that has built a simple, dual-issue RISC CPU core with integrated memory and multicore networking, intended to be implemented in massively parallel fashion. GloFo and Adapteva have built a chip at 28 nm that houses 64 CPU cores and achieves a claimed 100 GFLOPS of throughput—at only 2W of power draw and 10 mm² of die space. The two firms have partnered up to market this technology to potential foundry customers, for integration into their SoC solutions.

Partnerships like these obviously move well beyond the traditional contract manufacturing model, and they are a big part of GlobalFoundries' approach to attracting new customers.