Crossed lines

BACK in 1965, Gordon Moore, one of the co-founders of Intel (now the world's largest maker of microprocessors), pronounced his famous law: that the number of transistors which can be packed on to a sliver of silicon would double every 18 months. So far (after revising his estimate to two years), he has been proved correct. When he spoke, an Intel chip would have been impressive if it had had a few hundred transistors. The company's latest processor, the Pentium Pro, has 5.5m of them. But engineers are worried that the law may be due for repeal. The wispy-thin internal leads that connect a microprocessor's transistors are beginning to interfere with one another—like crossed lines in a busy telephone exchange. Fitting more transistors on to a chip will be difficult unless this “crosstalk” can be curbed.