14 DAY TRIAL // A bunch of researchers in the United States have come out with copper interconnections for the next generation of integrated circuits, that are alleged to increase the efficiency of the chips' connections with motherboards and other types of external circuitry.
The research team is comprised of Paul Kohl and Thomas L. Gossage, chair and Regent Professors at Georgia Tech's School of Chemical and Biomolecular Engineering. The two scientists explained that the current soldering methods involve melting tin solder between the chip and the board. Glue is added later in order to hold the two parts as close as possible, should mechanical shocks occur.
The scientists have replaced the tin solder connections with some copper cylinders. The result was stunning, and revealed that the cylinders are able to create stronger connections, thus improving the chip's performance. "Circuitry and computer chips are made with copper lines on them, so we thought we should make the connection between the two with copper also," said Professor Kohl.
While both solder and copper alloys can correct the small variations in the pieces' alignment, it seems that copper is more conductive than the lead alloy and is able to create stronger bonds with the adjacent electronic components.
The research has been financed by the Semiconductor Research Corporation, and allowed Kohl and its research partner, graduate student Tyler Osborn, to set the specifications of a new manufacturing process, that will substitute all the lead-based connection with all-copper links between the chips and the underlying pieces of circuitry (such as the printed circuit boards, for instance).
The first phase of the process uses electric current to coat a tiny piece of copper onto the surface of both pieces. The next step is to form a solid copper connection between the two small pieces of copper without the use of external electrical current. The copper pillar is extremely thin and fragile when manipulated at room temperature, so it has to be heated in a special oven in order to remove all its defects.
"I have also studied the optimal shape for the connections so that they are flexible and mechanically reliable, yet still have good electrical properties so that we can transmit these high frequency signals without noise," he said.
The research team is currently working with engineers from Texas Instruments and Intel, in order to perfect the new technology.