June 24, 2005 – Semiconductor Leading Edge Technologies Inc. (Selete) has developed a new polishing technology for the 45nm generation of chips, according to the Nikkei English News. The technology is basically a reversal of the process of metal electroplating, and it works to smooth down the circuit wiring layered over the transistors on the wafer without damage to the neighboring regions of insulator.
The technology makes use of a special carbon pad developed in cooperation with industrial filter maker Roki Techno Co. The pad is 40cm in dia. and is pocketed with some 200-300 holes. The carbon pad surface can act as a positive electrode and the bottom of the holes can act as a negative electrode. If a voltage is applied to this pad while the wafer is moved above the pad in the presence of an electrolyte liquid, metal from the surface of the circuit wiring will dissolve in a process of reverse-plating and flow down into the holes with the electrolyte liquid. The procedure effectively polishes the wafer surface without the use of physical force.
Since the pad can be fitted to the CMP machine now used for wafer polishing, its adoption for the 45nm generation of chips will not involve a major investment on the part of chipmakers.