The growth in the density and performance of microprocessors described by Moore's Law may go on only for the next eight to 12 years with existing technology, Intel chairman emeritus Gordon Moore told attendees at this week's International Solid-State Circuits Conference in San Francisco.
"We're talking 10, plus or minus two, years for conventional scaling," Moore said. But beyond that, technologies now under development may let developers keep up the pace.
"No exponential is forever. Your job is delaying forever."
A key problem will be the need to narrow the minimum width of the smallest wires on a chip, which today are 90 nanometers wide in the most advanced chip manufacturing process. Moores predicted new approaches may be needed for widths less than about 30 nanometers, which will be reached in a few generations of about two to three years each.
One promising new technology is the tri-gate transistor, in which the surface area of each transistor gate is increased to produce the equivalent of three gates for each transistor. Last year, Intel revealed plans to build such a transistor by the middle of the decade.
As with dual-gate transistors under development at IBM, such a design would allow Intel to increase electrical current and the performance of chips without burning up the transistor or leaking electricity.
"Below 30 nanometers it's not clear that the conventional devices will work. Something like that thin transistor ... looks like a very realistic possibility," Moore said.
Denser processors also will require another big step in the lithography or etching of chips, which Moore said will be "a tough transition". Greater density calls for etching with shorter wavelengths, added. He pointed to a possible solution in extreme ultraviolet lithography, which the chip industry consortium International Sematech will be researching.
Power consumption is another big issue as chips get denser, he added. Chips' voltage requirements are reduced with every generation, but Moore warned that it would be impossible to cut power indefinitely.
"This can't go on forever. You need at least a few hundred millivolts. I suspect something around one volt is going to be a limit, but I sure have been wrong on a lot of these other things that I suspected were going to be limited."
Some ultra-low-voltage Intel chips have power consumption of around one volt, but not those that run at mainstream Intel PC speeds of 2GHz and above.
Insight 64 principal analyst Nathan Brookwood agreed chip makers are facing bigger challenges in design and manufacturing.
"Every generation requires greater investment in [research and development] and manufacturing to make it work, because the low-hanging fruit in terms of semiconductor production was harvested years ago."