'Bridge tools' appear to be taking over 300-mm movement
By J. Robert Lineback
Semiconductor Business News
(04/26/01 09:15 a.m. EST)
MUNICH -- "Bridge tools"--a controversial concept in the industry's failed attempt to use 300-mm wafers three years ago--appears to be taking off in a big way as the migration to larger-diameter wafers moves ahead despite the severe downturn.
This time, IC manufacturers are embracing the concept of using bridge-tool platforms to do process development and tool-set integration on 200-mm wafers first, followed by an upgrade for volume production with larger 300-mm substrates.
Three years ago, major chip manufacturers--such as Intel Corp. and others around the world--fought the concept of using platforms that could handle 200- and 300-mm wafers because it added costs to already expensive 300-mm tools (see June 17, 1998, story).
But uncertainty in the marketplace and the need to accelerate development of next-generation process technologies has given bridge tools a big boost, according to equipment suppliers, analysts, and some chip makers at this week's Semicon Europa conference in Munich. In fact, bridge tool shipments are expected to surpass 300-mm dedicated systems next year in terms of the percentage of fab tools shipped, according to a new forecast by VLSI Research Inc.
Bridge tools will grow from just 11.2% of this year's total equipment shipments to 52.5% in 2005, according to VLSI Research. In contrast, 300-mm dedicated systems will go from 11.5% of tool shipments in 2001 to just 5% in 2005, according to the San Jose research firm.
"The bridge tool is going to account for the vast majority of 300-mm capable systems during the next fives years or more," said analyst G. Dan Hutcheson, president of VLSI Research. "Back in 1998, the concept touched off a huge controversy, but it did not make sense for equipment suppliers to be developing two different platforms for one generation of process technology," said Hutcheson, who helped to stir the industry debate three years ago when he endorsed a switch to "bridge tool" strategies.
Some opponents to bridge tools have become backers of the flexible-system concept, which enables platforms to be converted from 200- to 300-mm wafers within hours. "At one time, I felt it was fairly impractical, but now I feel it is absolutely the right way to go," said Raymon F. Thompson, president, CEO and chairman of Semitool Inc., the deposition and cleaning systems supplier in Kalispell, Mont. "It is crucial to where we are headed. Our 300-mm tools will be 200-mm compatible because it is now necessary."
The concept of what exactly is a bridge tool has shifted somewhat since three years ago, however. Early on, some early attempts at bridge tools merely extended 200-mm processing platforms so that 300-mm wafer handlers and chambers could be bolted on to the gear. But those attempts often resulted in a dead end, said Thompson and other executives on an executive panel at Semicon Europa on Wednesday.
"Often I hear customers referring to bridge tools as an existing piece of lithography equipment where you literally extract a 200-mm handler and put on a 300-mm handler. That's not the concept that ASML thinks is the wisest decision," said Dave Chavoustie, executive vice president of sales at ASM Lithography. The Dutch stepper and scanner supplier decided to create a whole new platform for 300-mm as part of its long-term strategy for next-generation processes. It is not trying to bridge the 300-mm demand from its workhorse platform that has been used for 11 years.
"Our approach to 300-mm was that we wanted to make a tool that was not perceived as a 'bridge tool,' although our 300-mm tool can be used for 200-mm," he said during the Semicon Europa panel discussion. ASML's target was to create a whole new platform that could be used by chip makers as a "single-learning process" for technologies that go as far as light exposure will take them--meaning mostly 300-mm fabs but also be able to accommodate 200-mm substrates in R&D and other production lines, if necessary, he said.
Hutcheson agreed that process development considerations are now weighing more heavily in the decision to buy bridge tools vs. dedicated 200- or 300-mm systems. The emphasis on bridge tools in 1998 was to help reduce the cost of the equipment supplier, which was unable to prepare two sets of systems for 200- and 300-mm fabs.
"The interesting thing is that lately I have found customers saying we have not only got to develop on 300-mm but also 200-mm," Hutcheson said. "They realize that they have to develop on two tool, if they don't have bridge tools."
While attention is shifting to 300-mm fabs, most semiconductor manufacturers still do process R&D on 200-mm substrates. "Of our 300-mm customers, probably 50% of them baseline processes on 200-mm tools and then convert the processes to 300-mm so they can get some level of confidence," said Donald S. Mitchell, president and CEO of FSI International Inc., a supplier of cleaning and resist processing systems in Chaska, Minn. "We try to make our 300-mm tools as close as possible to 200-mm. We have had a bridge tool strategy from the get go... It reduces risk."
But once a chip maker has gained confidence in 300-mm processes, there is little reason to use the 200-mm wafer capability in a platform, said Peter Kuecher, vice president and managing director of 300-mm fabrication activities at Infineon Technologies AG in Munich. He said 300-mm tools have improved substantially from 1998, when Infineon and partner Motorola Inc. started up their Semiconductor300 joint venture in Dresden, Germany. To tap those improvements, some chip makers might opt to use bridge tools for initial 200-mm production at a particular technology node, he added, but beyond that companies won't switch back and forth between the two diameters.
"In the beginning you want to cover risk, but as soon as you know and you have made a decision [to push ahead with 300-mm], there is no good reason for going with 200-mm," Kuecher said. |
