The advantages of copper circuitry is that it can be thinner than aluminum circuitry allowing chips to be smaller. When it comes to semiconductor design and manufacturing, smaller chips are cheaper, faster and better. Smaller chips are faster because electrical signals travel shorter distances. Smaller chips are cheaper because more chips can be manufactured from a single silicon wafer. Smaller chips are better because they require less power and generate less heat. However before copper circuitry can be truly exploited – and analysts at Robertson, Stephens & Company LLC think the advantage of copper circuitry in today’s state of the art chip designs is negligible and fabricating current chip designs with copper rather than aluminum would probably prove more costly not less. Two other obstacles confront designers of next generation semiconductor components. The first is electrical interference or cross-talk generated as chips get smaller and circuit density increases. Semiconductor designers will have to design chips to minimize interference and the high density circuitry of next generation chips will, in Sematech’s opinion, require some type of insulation. The load dielectric constant (resistance to interference) of vacuum is one, and that of glass is four. Sematech says it’s now working with materials that measure 2.5 to 3, and that it’s got a substance with a dielectric constant of 2 on its way. Sematech says it has a substance working on a single layer of metal that will support multiple layers of metal. After the complex design issues of high density next generation semiconductors are overcome, the design must be transferred to silicon. New lithography methods will be required to transfer chip designs to ever shrinking die sizes. Sematech’s interconnect group says it’s already drawing spots and lines working with conventional lasers below 0.15 microns (it’s not drawn a circuit as such), and is already supplying this to tool makers. As Robertson, Stephens & Company LLC notes, one clear beneficiary of the move to copper circuitry will be the semiconductor capital equipment providers. The semiconductor manufacturers will need to upgrade their equipment in order to produce next generation chip designs.
