SAN FRANCISCO – Chip stacks were in the spotlight at Semicon West as a way to compensate for the laws of physics pushing chip makers off the path of Moore’s Law. AMD described a packaging victory with its Fiji graphics chip in one session, while a Qualcomm engineering manager warned about manufacturing disconnects ahead in another.
At the transistor level, memory specialists catalogued the challenges and hopes for 3-D NAND. In other sessions, lithographers described step-wise progress toward their next-generation systems.
In a sign of the rising importance of chip stacking the International Technology Roadmap for Semiconductors will now focus mainly on packaging-related topics. CMOS scaling, once the focus of the ITRS, has become the territory of a handful of consolidated companies now, said Bill Bottoms, an ITRS participant and CEO of Third Millennium Test Solutions.
“A majority of the improvement in semiconductors going forward will come from heterogeneous integration mainly in complex systems-in-package -- bringing things closer together is the only way to get the improvements we need,” Bottoms said.
As an example, he showed a teardown of an Apple Watch with 32 active and passive components packed into it a device Apple calls the S1 SiP. “Smartphones have been the industry driver, but IoT is expected to be the next driver,” he said.
The ITRS 2.0 document not yet released will call for ten-fold improvements in the 2.5- and 3-D stacks that Bottoms described as “in their infancy” today. For such designs over the next 15 years, costs and power/function need to decrease by four orders of magnitude while the number of point-to-point connections must go up by six orders of magnitude, he said.
The cost and complexity of advanced packages are already skyrocketing, said Calvin Cheung, vice president of business development and engineering at packaging specialist ASE in Taiwan, speaking in a keynote panel.
“Our biggest concern is cost,” Cheung said. “We used to use a few thousand interconnects in a package, now in a 2.5-D device we have a couple hundred thousand interconnects in a very small space,” he said.
Next step: Qualcomm calls for shared data mining
ITRS planners see Apple's S1 with 32 components as an example of IoT driving systems-in-package advances.