December 19, 2007 – ShinMaywa Industries has developed a method for sputtering copper thin films onto semiconductor substrates that wastes virtually none of the starting material, according to the Nikkei Business Daily.
With current techniques the copper target is worn unevenly and needs to be frequently replaced after only half of the material is used. The new method uses magnets to narrow the plasma (positively charged argon ions) to a horizontal layer in the middle of the vacuum chamber. Applying a voltage to the copper target attracts the ions upward, striking the target and expelling copper atoms, which are ionized as they pass downward through the plasma to accumulate as a film on the chip substrate.
The argon atoms strike the entire surface of the copper target, wearing it evenly and consuming it with “basically 100% efficiency,” the paper notes, and the process can accommodate 300mm wafers by adjusting the plasma size with the magnets.
The company plans to start selling devices based on the technology in late 2009.