Copper connections for high-speed computing

Copper connections for high-speed computing

Caption: Graduate student Todd Spencer and Regents' professor Paul Kohl have developed an improved signal transmission line, made of an organic substrate, to link high-speed signals between computer chips.

Credit: Georgia Tech Photo: Gary Meek

As computers become more complex, the demand increases for more connections between computer chips and external circuitry such as a motherboard or wireless card. And as the integrated circuits become more advanced, maximizing their performance requires better connections that operate at higher frequencies with less loss.

Improving these two types of connections will increase the amount and speed of information that can be sent throughout a computer, as per Paul Kohl, Thomas L. Gossage chair and Regents professor in Georgia Techs School of Chemical and Biomolecular Engineering. Kohl presented his work in these areas at the Materials Research Society fall meeting.

The vertical connections between chips and boards are currently formed by melting tin solder between the two pieces and adding glue to hold everything together. Kohls research shows that replacing the solder ball connections with copper pillars creates stronger connections and the ability to create more connections.

Circuitry and computer chips are made with copper lines on them, so we thought we should make the correlation between the two with copper also, said Kohl.

Solder and copper can both tolerate misalignment between two pieces being connected, as per Kohl, but copper is more conductive and creates a stronger bond.........