AMD CTO Talks About The Transition towards 7nm

AMD will be among the first parties to make a transition to fabbing at 7nm, their Chief Technology Officer (CTO), Mark Papermaster, talks about that transition in an interview.

According to Papermaster 7nm might be one of the biggest challenges yet, but also states thatA MD is making good progress. To gear up for 7nm, “we had to literally double our efforts across foundry and design teams…It’s the toughest lift I’ve seen in a number of generations,” perhaps back to the introduction of copper interconnects, said Mark Papermaster, in a wide-ranging interview with EE Times:

The 7nm node requires new “CAD tools and [changes in] the way you architect the device [and] how you connect transistors—the implementation and tools change [as well as] the IT support you need to get through it,” he said. Both AMD’s Zen 2 and Zen 3 x86 processors will be made in 7nm. “It’s a long node, like 28nm…and when you have a long node it lets the design team focus on micro-architecture and systems solutions” rather than redesign standard blocks for the next process, Papermaster said.

The CPUs and GPUs AMD is shipping today were among its first designs in 14/16nm nodes using double patterning lithography and FinFET transistors. For that work, “our partnerships with foundries and the EDA industry had to deepen. In 7nm it requires even deeper cooperation [because] we have quad patterning on certain critical levels [where] you need almost perfect communications between the design teams,” he said.

Papermaster expects foundries will begin to use extreme ultraviolet (EUV) lithography starting in 2019 to reduce the need for quad patterning. EUV “could bring a substantial reduction in total masks and thus lower costs and shorten cycle time for new designs,” he said.

“Foundries will introduce [EUV] at different rates but…I urge them all to go as fast as they can,” he said.

To date, AMD has used Globalfoundries, its former fab group, to make its x86 CPUs and TSMC to make its graphics processors. “They have both been aggressive in 7nm and that’s good for the industry. The gap has closed versus where Intel is at and that’s an incredible juncture in the industry that people have predicted and now were seeing it,” Papermaster said.

“The call to arms here is to reduce the cost of wafer-level fan-out and similar technologies in active development across the industry. There are good demos, but it’s not pervasive, volumes are not high enough yet and we have not achieved the cost points we need,” he said.

The technology is key for “an era of Moore’s law-plus where we’re getting new density advantages at each node and cost advantages as each new node matures, but mask costs are going up and chip frequencies are not going up, so how we put solutions together is critical to sustain the pace of development,” he said.

In software, “my call to action for the EDA community…is to redouble their efforts to take advantage of more CPU cores and parallelism…As the processing required for 7nm escalates…their algorithm optimization needs to take advantage of the very technology they are helping us manufacture,” he said, noting AMD’s new Epyc processors sports 32 dual-threaded cores.

“Mask data post processing is highly parallel, and I’m starting to see good enhancement there. I’d like to see it extend to physical design and verification where we spend a lot of resources,” Papermaster said. Meanwhile, AMD has “embraced emulation as a way to accelerate our verification and marry co-verification of software and hardware,” he added. It’s one of many ways AMD has been punching above its weight to compete with rivals Intel and Nvidia.

“In our turn around, we couldn’t just throw hundreds of designers at a problem, so we designed in more modularity to reuse circuits across client CPUs, GPUs and semicustom chips…We stayed on and even improved time from first silicon to tape out as complexity went up with FinFETs and…verification complexity,” he said.

“The AMD team has always been known for deep talent. We hit a point where we had to pull together to build great products, and there was no room for in-fighting,” he said.