From EETimes:
<<<Posted: 9:00 p.m., EDT, 7/9/98
Equipment makers look to make gold from copper
By Craig Matsumoto
with additional reporting by Brian Fuller
SAN FRANCISCO - Despite the shaky business climate, the exhibitors that head to Semicon/West next week intend to demonstrate progress in preparing for the next generation of deep-submicron manufacturing.
While the push to 300-mm (12-inch) wafer manufacturing has stalled, vendors are moving into higher-margin areas, such as tools for building copper interconnects and "bridge" tools that can cover both 200- and 300-mm-manufacturing needs. Meanwhile, lithographic technology is marching forward, and attention to tool productivity is on the rise as the focus has shifted away from yields.
With overseas customers having slashed travel budgets, Semicon/West exhibitors have been trading predictions about how empty the usually enormous show is likely to be this year.
"As far as the business conditions are concerned, they suck," said Dan Hutcheson, president of VLSI Research Inc. (San Jose, Calif.), which tracks the semiconductor-equipment industry. "There's no visibility into the first half of next year, unless you're in test."
The industry's book-to-bill ratio was in a freefall between January and April, going from 0.99 (nearly one booking for every shipment) to 0.77. But the indicator recovered in May, to a preliminary figure of 0.80.
For all its negative effects, the slump may offer a silver lining in that it may hasten the shift to copper. "If anything, I think [the transition is] accelerating," said Rick Hill, chief executive of Novellus Systems Inc. (San Jose). "When the industry is tough, it's tough to get expansion capital," so money is instead channeled into R&D to develop better processes and thus wring more productivity from existing fabs.
Novellus plans to unveil the first complete set of tools for copper production, although not all of the tools will come from in-house: Lam Research Corp. and Integrated Process Equipment Corp. signed on with Novellus to provide their chemical mechanical planarization (CMP), or wafer-polishing, tools.
By contrast, Applied Materials Inc. (Santa Clara, Calif.) has been able to cover much of the copper process with its own tools.
Still, Novellus hopes to surpass Applied by providing physical vapor-deposition tools to handle all three phases of building a copper structure: construction of the barrier layer, usually of tantalum pentoxide; construction of the seed layer, made of thin copper, to adhere to trench and via walls; and electroplating of the copper itself.
Achieving the seed layer has proved difficult, Hutcheson said, but "the real missing link has been a good electroplating tool." Indeed, that's the one piece of the puzzle for which Applied lacks an in-house resource.
The progress in copper manufacturing has been promising, said Tom Bonifield, a Texas Instruments Inc. research fellow. "The equipment industry is responding very well. They've gotten the message that this is the equipment we want them to focus on." But given that the equipment is new and has therefore yet to undergo full production runs, Bonifield expects it to be difficult to control in the early going.
What's more, not everyone remains convinced that the industry is on the right track. "I'm under the impression that the Japanese semiconductor manufacturers are not convinced this is the way to get copper done," said Ron Leckie, chief executive of research firm Infrastructure (San Jose).
Leckie's perception is that Japanese chip makers are uncomfortable with the entire process and that they would prefer an approach using chemical, rather than physical, deposition.
Along with throughput and size, cost factors confront equipment makers. "The chip vendors are talking to the equipment vendors about getting the cost out of the equipment," Leckie said. Among the more radical approaches is vertical stacking of the wafer chambers, to reduce the footprint of front-end equipment.
Tooling over the bridge
The other big trend is toward bridge tools-machines that can handle 200-mm and, with different chambers, 300-mm wafers.
A force behind the trend has been the mounting development-cost considerations for 300-mm manufacturing; indeed, cost concerns are said to have pushed out the next-generation technology's arrival date by years. Stepper manufacturers were the first to decide to build bridge tools in favor of exclusively 300-mm tools, and front-end equipment companies such as Applied and Varian followed suit. Bridge tools surfaced at Semicon last year and they should be all over the show this year, Hutcheson said.
Such tools also have been driven by the poor economic picture in the semiconductor industry. Falling revenues have prompted silicon vendors to ignore quarter-micron manufacturing and move quickly to 0.22- or 0.1-micron line widths, thereby gaining efficiencies without having to buy 300-mm tool sets.
"A number of capital-equipment companies essentially have [300-mm] inventory that's going to be non-sellable," said Jim McKibben, president of etch-equipment vendor Tegal Corp. (Petaluma, Calif.) "By the time [300 mm] gets implemented, the industry will be at 0.15 or 0.13 [micron], and everything at 0.25 [will be] worthless."
Indications are that the 0.18-micron target will be popular in lithography as well. Microscan, Canon and ASML are all expected to field new lithography tools at the show. And Dupont Photomasks Inc. (Round Rock, Texas) will participate in a seminar, put on by FSI International Inc. (Minneapolis), to tout the increased importance of reticles to chip-making technology.
Ken Rygler, executive vice president of marketing for Dupont Photomasks, said masks have gone through a "dormancy," requiring no technological changes and providing little in the way of technology themselves. That trend is attributed to the 5X stepper craze, which used existing masks to make images one-fifth their size. As a result, masks were no longer tied directly to device performance and yield.
"When the industry went to 5X, the mask became five times easier. It became difficult to build a bad mask," Rygler said. "At about the quarter-micron level, masks are emerging as an enabling technology that does indeed contribute to device performance and device yields."
Optical proximity correction and phase-shift masks let chip makers fine-tune their lithography processes without having to upgrade steppers. Both provide features that are too small to print on the wafer but that enhance focus or fidelity of the image.
"Semiconductor companies have found that by a combination of RISC technology, CMP, technology and stepper technology, they can extend their lithography specifications further than they thought," Rygler said. "Some people are talking about going to 0.15 micron with 248-nm" lithography.">>>> |
