The steady 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 today's conventional technology, the author of that law said Monday.
"We're talking 10, plus or minus two, years for conventional scaling," Intel Chairman Emeritus Gordon Moore told attendees at the International Solid-State Circuits Conference (ISSCC). But beyond that, technologies now under development may let developers keep up the pace.
"No exponential is forever. Your job is delaying forever," Moore said.
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. 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, he said.
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. Intel last year revealed plans to build such a transistor by the middle of the decade. As with dual-gate transistors under development at IBM Corp., such a design should allow Intel to increase electrical current and thus the performance of chips without burning up the transistor or leaking electricity, the company said.
"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 lithography, or etching of chips, which Moore said will be "a tough transition." Greater density calls for etching with shorter wavelengths, he said. He pointed to a possible solution in extreme ultraviolet lithography, which the chip industry consortium International Sematech will be researching at a facility in Albany, New York.
Power consumption is another big issue as chips get denser, he added. Chips' voltage requirements are reduced with every generation, but it probably won't be possible to cut power indefinitely, Moore said.
"This can't go on forever. You need at least a few hundred millivolts. I suspect something around 1 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," Moore said. Some current ultra-low-voltage Intel chips have power consumption in the vicinity of about 1 volt, but not those that run at mainstream Intel PC speeds of 2GHz and above.
The challenges in chip design and manufacturing are bigger than they seem and bigger than ever, agreed Nathan Brookwood, principal analyst at research company Insight 64, in an interview Monday.
"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," Brookwood said.