14 DAY TRIAL // Since semiconductors are nearing the limit of what they can accomplish by sticking to a single plane, foundries have been doing their best to come up with new ways of building them, even if it means going 3D.
Tri-gate transistors were the first thing that happened, then the idea arose for three-dimensional memory chips.
The latter project has come a long way, as we reported earlier when the Hybrid Memory Cube was detailed.
That leaves other types of ICs (integrated circuits), like the ones manufactured by TSMC (Taiwan Semiconductor Manufacturing Company) and Globalfoundries.
As it happens, Globalfoundries has reached a milestone of its own, which it, interestingly enough, shared with the world just as the news about HMC came out.
The foundry has demonstrated its first functional 20nm silicon wafers with integrated Through-Silicon Vias (TSVs) at the Fab 8 campus in Saratoga County, N.Y.
TSVs are vertical vias etched in a silicon wafer. They are filled with a conducting material that allows communication between integrated circuit stacked vertically.
"Our industry has been talking about the promise of 3D chip stacking for years, but this development is another sign that the promise will soon be a reality," said David McCann, vice president of packaging R&D at GLOBALFOUNDRIES.
"Our next step is to leverage Fab 8's advanced TSV capabilities in conjunction with our OSAT partners to assemble and qualify 3D test vehicles for our open supply chain model, providing customers with the flexibility to choose their preferred back-end supply chain."
Globalfoundries experimented with these chips before, but that was on the 28nm manufacturing process, not 20nm.
TSVs actually posed some problems when migrating from one to the other, but a proprietary contact protection scheme allowed Globalfoundries to integrate TSVs into 20nm-LPM without much fuss, at the same time demonstrating SRAM functionality with critical device characteristics.