Japanese Take Aim at 64-Megabit D-RAM; U.S. Experts Skeptical : Triumphant NTT Working on Even Bigger Chips
The president of Nippon Telegraph & Telephone Corp., which last week announced that it had developed a 16-megabit semiconductor, on Thursday said it is at work on a computer chip four times that large.
Hishashi Shinto, meeting with a group of foreign correspondents, said the telecommunications giant is attempting to develop a 64-megabit D-RAM (dynamic random access memory) chip and is spending about $300 million to build two new laboratories where it will begin research on even larger chips--those with capacity of 256 megabits or more.
Chips with such huge densities far exceed current technology, and most industry experts believe that it will be several years before even 16-megabit D-RAMs can be produced in volume. A 256-megabit chip would be able to store about 256 million bits of information, or 1,000 times more than the most widely used chip today, the 256-kilobit D-RAM.
Companies in Japan and the United States have begun testing 4-megabit chips, and are expected to begin making production runs for sampling next year. IBM announced last month that it is producing a 4-megabit chip, and chip industry analyst George Haloulakos of the Dain Bosworth brokerage firm, said he “would be very surprised if IBM isn’t working on 16-megabit and above technology.”
Memory chips are used to store information in such electronic products as computers, dishwashers and videocassette recorders.
U.S. engineers reacted to NTT’s disclosure skeptically, saying they believe that attempts to build a 64-megabit chip will come up against a wall of natural physical limitations. At Dallas-based Texas Instruments, the only major U.S. merchant semiconductor firm still making D-RAMs, researchers are experimenting on 16-megabit chips but believe that other technologies will be needed for higher-density devices.
More storage capacity is built into the chips through miniaturization techniques. Already, the transistors are so closely jammed on a 1-megabit chip that they are no further apart than 1 micron--a distance equivalent to the length a human fingernail grows in one hour. Texas Instruments spokesman Stan Victor said engineers believe that the natural limit to this shrinking process will be reached at three- or four-tenths of a micron--the distance that, with today’s technology, would separate features on a 64-megabit chip. Any greater density than that, he said, would mean dealing in subatomic particles.
Shinto said that NTT needs to continue refining its 16-megabit technology before it can be commercialized. He said: “Two or three years (will be needed) to materialize it in the form of a final product. Then we would go into joint development with a multiple number of companies on an international scale . . . leading to final development of a commercial product.”
Nonetheless, Shinto said that NTT, a government monopoly until it became a private company in 1985, is willing to sell the technology it used to make the prototype 16-megabit chip to any other company, foreign or Japanese.
Shinto said that work on a 64-megabit chip is being conducted at NTT’s Atsugi Electrical Communications Laboratories, one of nine company labs. “If we surpass 64 megabits, we will need different facilities,” he said, explaining the plans for the new research facility.
Two types of technology, he said, must be developed to produce a chip of more than 64 megabits--one to upgrade the precision of printing circuits on the wafer and the other to improve the material used in the wafer itself.
A facility to develop the printing technology, he said, is being constructed in Ibaraki prefecture, north of Tokyo, and the new wafer facility is going up at the Atsugi Laboratory outside Tokyo.
“There are many unknown factors,” he said. “Even how long the construction will take is not known.”
Shinto said he does not think that NTT’s development of the 16-megabit prototype demonstrates that Japan has advanced beyond the United States in technology.
“It just happened that we developed the 16-megabit ahead of the United States,” he said. “In terms of advanced technology as a whole, I never think of Japan as walking ahead of the United States. Although the gap between Japanese and American capabilities has been shrinking, in overall terms, the United States is ahead of us.
“In the mentality of researchers, there is still a gap between the two countries. American researchers have a philosophical way of thinking. They have all studied natural sciences. Japanese have no such mentality. They are just working with materials.”
Times staff writers Sam Jameson reported from Tokyo and Donna K. H. Walters from Los Angeles.
