International EUV Symposium: CaFl is still more expensive than gold

• To achieve commercial viability, EUV (extreme ultraviolet) scanners must reach throughput levels of about 120 wafers per hour. The current prototypes provide up to 90 wafers per hour throughput, or 60 wafers per hour, considering servicing.
• Industry´s desired per-scanner target cost is $20 million. Some experts predict EUV scanners to cost $50 million or more.
• For commercial EUV scanners to be ready for production at the 45-nm process technology node, which moves into commercial production in 2007, Intel and other companies need beta EUV tools by 2005.
• Optimism about the long-term potential of EUV lithography, which uses 13.5 nm wavelength light is balanced by fears that the solution may exceed the budgets of all but a few manufacturers of microprocessors and memories.
• At the 45-nm node a logic chip might require four mask levels of EUV lithography for critical layers, another 11 mask layers supplied by 193-nm lithography, and the rest with 248-nm tools.
• Intel´s primary goal is to make EUV work for critical dimensions at the 45-nm node. The default is to make 157-nm work, or to make 193-nm lithography work by using more reticle enhancement techniques.
• For the 32-nm node expected in 2009, EUV scanners and masks will be needed for nine layers. The issue for 157-nm lithography is purely a calcium fluoride issue: high-quality calcium fluoride is more expensive than gold. For the 193-nm scanner lenses now coming to the market, about 10 percent of the lens material comes from calcium fluoride. For the 157-nm scanners, all of the lenses are made from the CaFl material.
• To get high-throughput EUV systems, the laser source must be improved to generate more of the extreme ultraviolet radiation, or light. Today´s best YAG lasers generate only about 10 Watts of radiation, that must be boosted to 100 Watts or more for high-throughput commercial production.
• The sensitivity of the resist must be improved. The desired target is 2 milliJoules of sensitivity for commercial EUV resists.
• Currently ASML is the only EUV beta tools vendor. However, Japanese Canon and Nikon promise to ship their prototypes by 2005.

Source: EE Times

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