Finding a way to use copper as the material for connecting the tiny switches in microprocessors has been the Holy Grail of semiconductor research. Why? Copper  is a superior conductor of electricity, making it possible to shrink the electronic devices even further while further increasing performance. But copper poses problems. After years of effort, however, IBM researchers announced a breakthrough in copper circuitry that could profoundly affect the electronics industry. If you're interested in this new world of tiny wiring, find out how it works.