Globalfoundries has demonstrated a first working 20nm chip based on Through-Silicon Vias (TSV). The TSV capabilities will allow stacking of multiple chips on top of each other.


The Through-Silicon Vias are basically vertical vias etched in a silicon wafer and filled with a conducting material, and thus enabling communication between multiple stacked chips. Globalfoundries used via-middle approach for TSV integration which means that the TSVs are inserted after the wafer have completed Front End of the Line (FEOL) flow in order to aviod high temperatures of the FEOL process and enabling them to use copper as the TSV material.


There has been a lot of talk about 3D stacking of chips and even Nvidia is looking into it, for its memory stacking on top of the GPU. Unfortunately, Globalfoundries or Nvidia did not say when the 20nm TSV process will actually be ready for volume production so we might have to wait a bit longer to see some chips stacked on top of each other.


AMD will definitely be happy with this key milestone as it was stuck at 32nm for quite some time.

Source: Globalfoundries.com