EUV Suffers New Setback

ASML Holding’s initial, production-worthy extreme ultraviolet (EUV) lithography tool has suffered a setback during a recent trial run at Taiwan Semiconductor Manufacturing Co. Ltd. (TSMC).

TSMC disclosed the problem during a public presentation at the 2014 Advanced Lithography conference in San Jose, Calif. During the trial run at TSMC, the EUV source crashed due to a misalignment of the laser mechanism within the EUV source itself. This, in turn, caused the EUV scanner to go down. “It was a laser misalignment,” said Jack Chen, department manager of the Next Generation Lithography Department at TSMC.

ASML/Cymer plans to fix the problem, according to Chen, who is still bullish about EUV. In fact, TSMC still plans to insert EUV at the 10nm node despite the problems with the EUV tool. “That’s our goal,” Chen said.

Still, the disclosure represents the latest in a series of setbacks for the problem-plagued EUV. Many of the problems with EUV can be traced to the power source. In fact, EUV continues to get pushed out amid a myriad of technical problems, such as the power source, EUV masks and resists.

Source of the problem
ASML’s first production EUV scanner, the NXE:3300B, was recently shipped to TSMC. Intel, Samsung and other customers are supposed to obtain the tool by this year as well. The EUV tool has a numerical aperture (NA) of 0.33, a 4X magnification scheme and a resolution of 22nm (half-pitch).

The NXE:3300B, which was shipped to TSMC, was supposed to have an integrated 30 Watt EUV source from ASML/Cymer. But during the trial run around or before January 31, the laser mechanism broke, causing the system to go down, according to TSMC. A spokesman from ASML said the machine is up and running at TSMC as of this week.

Still, the issues caused some damage to the internal components in the EUV source, namely the collector, Chen said. The EUV source itself is based on laser-produced plasma (LPP) technology. In LPP, plasma is generated by a laser pulse hitting a target. The source also makes use of a pre-pulse laser and a master-oscillator power amplifier (MOPA), which will help generate more EUV power.

The source is being developed by Cymer, which was recently acquired by ASML. ASML/Cymer promised to ship a 100 Watt source by the end of 2012. So far, in the lab, Cymer has demonstrated the ability to generate 40 Watts and 50 Watts of EUV power.

A 55 Watt source translates to an EUV throughput of 43 wafers an hour. However, the industry is looking for an 80 Watt source, which could make EUV somewhat viable in chip production. An 80 Watt source will enable an EUV throughput of 58 wafers per hour. By 2015, ASML hopes to ship an EUV scanner with a 250 Watt source, which translates to a throughput of 126 wafers an hour.

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