Semiconductor manufacturers are also running afoul of basic statistics. Chip-makers mix small amounts of dopant into silicon in a manner analogous to the way paint-makers mix a few drops of beige into white paint to create a creamy off-white. When homeowners paint walls, the color seems even. But if they could examine a tiny patch of the wall, they would see slight variations in color caused by statistical fluctuations in the concentration of beige pigment. When microchip components were bigger, the similar fluctuations in the concentration of dopant had little effect. But now transistors are so small they can end up in dopant-rich or dopant-poor areas, affecting their behavior. Here, too, Packan says, engineers have “no known solutions.”
Ultimately, Packan believes, engineering and processing solutions can be found to save the day. But Moore’s Law will still have to face what may be its most daunting challenge-Moore’s Second Law. In 1995, Moore reviewed microchip progress at a conference of the International Society for Optical Engineering. Although he, like Packan, saw “increasingly difficult” technical roadblocks to staying on the path predicted by his law, he was most worried about something else: the increasing cost of manufacturing chips.
When Intel was founded in 1968, Moore recalled, the necessary equipment cost roughly $12,000. Today it is about $12 million-but it still “tends not to process any more wafers per hour than [it] did in 1968.” To produce chips, Intel must now spend billions of dollars on building each of its manufacturing facilities, and the expense will keep going up as chips continue to get more complex. “Capital costs are rising far faster than revenue,” Moore noted. In his opinion, “the rate of technological progress is going to be controlled [by] financial realities.” Some technical innovations, that is, may not be economically feasible, no matter how desirable they are.
Promptly dubbed “Moore’s Second Law,” this recognition would be painfully familiar to anyone associated with supersonic planes, mag-lev trains, high-speed mass transit, large-scale particle accelerators and the host of other technological marvels that were strangled by high costs. If applied to Moore’s Law, the prospect is dismaying. In the last 100 years, engineers and scientists have repeatedly shown how human ingenuity can make an end run around the difficulties posed by the laws of nature. But they have been much less successful in cheating the laws of economics. (The impossible is easy; it’s the unfeasible that poses the problem.) If Moore’s Law becomes too expensive to sustain, Moore said, no easy remedy is in sight.
Actually, that’s not all that he said. Moore also argued that the only industry “remotely comparable” in its rate of growth to the microchip industry is the printing industry. Individual characters once were carved painstakingly out of stone; now they’re whooshed out by the billions at next to no cost. Printing, Moore pointed out, utterly transformed society, creating and solving problems in arenas that Gutenberg could never have imagined. Driven by Moore’s Law, he suggested, information technology may have an equally enormous impact. If that were the case, the ultimate solution to the limits of Moore’s Law may come from the very explosion of computer power predicted by Moore’s Law itself-“from the swirl of new knowledge, methods and processes created by computers of this and future generations.”
The idea sounds far-fetched. But then Moore’s Law itself sounded far-fetched in 1965.