EUV Power Source Vendors to Boost Efforts
By Mark LaPedus, SemiMD senior editor
Delays for the power source technology continue to plague extreme ultraviolet (EUV) lithography.
The main EUV scanner vendor, ASML Holding NV, has recently shipped its pre-production tool to Intel, Samsung, Toshiba, Hynix and TSMC.
But as reported, the throughput is far below the stated target levels, due in part to the delays in the power source. Realizing they are behind the curve, the three main EUV source vendors — Cymer, Gigaphoton and Xtreme — are separately stepping up their efforts in the arena for good reason.
At Taiwan Semiconductor Manufacturing Co. Ltd. (TSMC), for example, the silicon foundry giant has begun using ASML’s NXE:3100 pre-production EUV tool in R&D. The NXE:3100 is using a light source from Cymer Inc.
S.Y. Chiang
In a recent interview with SemiMD, Shang-Yi Chiang, senior vice president of R&D at TSMC, said the silicon foundry giant is pleased with ASML’s EUV tool and its ability to process 20nm test devices in an R&D setting. “The technology works well,” Chiang said.
TSMC printed a 20nm device with the EUV tool on the first pass and without a glitch, he said. But as before, the problem is the throughput due to the light source. With ASML’s tool, TSMC is reportedly producing two wafers an hour. “We want 100 wafers an hour,” he added.
Recently, Cymer vowed to accelerate its EUV source efforts. Through a company spokeswoman, Paul Bowman, senior vice president, chief financial officer and secretary for Cymer, issued this statement: “Cymer’s investment in EUV started in 2001 and has been increasing ever since. The company has invested over $400 million in EUV source development since inception of the program. Currently Cymer has built eight 3100 sources with four of these sources currently producing wafers at chipmakers. Earlier this year the company received a multi-unit order valued at over two hundred million dollars for the next generation of EUV light sources that will support the ASML NXE:3300 lithography system.”
Rival Ushio Inc. said its EUV lithography source subsidiary, Xtreme technologies GmbH, is also making progress. The company recently said its EUV source has achieved an output of 30 Watts at an intermediate focus under a duty cycle of 100 percent.
The third player, Japan’s Gigaphoton, outlined its strategy at the IEEE SFBA Nanotechnology Council meeting in Santa Clara, Calif. on Tuesday (Nov. 15).
For some time, Gigaphoton has been developing an alpha/beta tool, dubbed the Engineering Test Source (ETS). Last year, the ETS demonstrated 104 Watts of power, but with a maximum operating time of around 1 hour. Earlier this year, the ETS demonstrated 42 Watts of power and around 7 hours of operating time.
The company’s first production-worthy EUV light source, dubbed the GL200E, is slated for introduction in mid-2012, with shipments due by the end of 2012, said Hakaru Mizoguchi, chief technology officer for Gigaphoton.
Gigaphoton outlines EUV source roadmap (Source: Company)
The GL200E will ultimately achieve 250 Watts of power. In 2013, the company hopes to roll out the GL200E+, a 350 Watt EUV source. Following that system, it plans to ship the GL400E, a 500 Watt unit.
In contrast, rival Cymer has already installed five production-worthy EUV sources in the field, which are operating in conjunction with ASML’s NXE:3100.
In other words, Gigaphoton is behind Cymer — at least for now. Phil Alibrandi, director of the sales and account management division at Gigaphoton USA Inc., said it’s far too early to declare a winner in the EUV source business.
At present, ASML is shipping the NXE:3100, a pre-production machine. The real test comes when ASML ships the NXE:3300, its first full-blown EUV production tool. That tool is expected to have a throughput of 125 wafers an hour by 2013.
Gigaphoton insists it will deliver the GL200E in time for the EUV production era. “I don’t think (EUV) high-volume manufacturing will happen until 2014 to 2017,” Alibrandi said. “2014 will be the early adopters. There is plenty of time” for Gigaphoton to prove the technology and gain traction in the marketplace.
Gigaphoton contends that it has a “better mousetrap” than rival technologies. EUV sources are based on three basic technologies: laser-produced plasma (LPP), discharge-produced plasma (DPP) and laser-assisted discharge plasma (LDP).
Configuration for Gigaphoton's EUV source in a fab (Source: Company)
Cymer and Gigaphoton are pursuing LPP. Xtreme is pushing LDP. At Gigaphoton, the GL200E produced its first “EUV light on (a prototype) source with 18 Watt equivalent level at present,” Mizoguchi said. “Next target is 50 Watt level demonstration (in) 1Q 2012.”
Gigaphoton’s LPP light source makes use of a CO2 laser. The laser hits a series of Tin (Sn) droplets from a mechanism, which cause EUV emission at 13.5nm.
The stability of the droplet shooting mechanism is the issue right now, he said. Sn debris falls on the collector mirror. The ions damage the multi-layer film on the collector mirror. As a result, the reflectance of the collector mirror is lowered within a short period of time, thereby lowering the output.
For debris mitigation, the company will make use of magnetic fields. This technology, coupled with the combination of a pre-pulse solid-state laser and a main pulse CO2 laser, is designed to suppress the debris.
The droplet mechanism “is the most difficult problem,” Mizoguchi said. “The droplet technology is like an inkjet printer. But the inkjet printer operates at room temperature.”
Still, Gigaphoton is making progress. “Our final goal (with the) GL-200E is 250 Watts and the feasibility is supported by high CE experimental data,” he added.
Gigaphoton devises GL200E EUV source (Source: Company)
