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Product Briefing Outline: ASML has introduced the ‘TWINSCAN' XT:1900i. In combination with ASML proprietary low k1 capabilities, this new system is designed to extend optical immersion lithography for volume production at the 40nm half-pitch dimensions with an overlay specification of 6nm (SMO). ASML's newest 193-nm wavelength immersion scanner uses a 1.35 NA inline catadioptric lens assembly that is near the practical limit for water-based immersion technology. ASML expects to begin shipping the XT:1900i by mid 2007.

Problem: The TWINSCAN platform was introduced in 2000 as critical wafer measurements proved a bottleneck to wafer throughput in the litho cell. The TWINSCAN system's dual-stage technology separates the process of wafer exposure from metrology and performs both processes in parallel, while improving throughput by more than 50 percent, according to the company. In parallel with productivity improvements optical lithography has been pushed to achieve imaging significantly below the wavelength of light. Innovations in optical assemblies, polarization control have been required for volume production applications. Using an immersion fluid between the wafer and the lens enhances depth of focus (DOF) for a given numerical aperture. Immersion also allows lens designs with numerical apertures significantly larger than 1.0, therefore allowing improved resolution.


Solution: ASML's newest 193-nm wavelength immersion scanner uses a 1.35 NA inline catadioptric lens assembly that is near the practical limit for water-based immersion technology. The system employs an ultra-k1 package, consisting of QUASAR XL, LithoGuide ILIAS, DoseMapper, Reticle Shape Correction, CDFEC and Focus Spot Monitor. The XT:1900i illuminator features polarization at maximum throughput, and extremely homogeneous pupil fill, that is adapted to ultra low-k1 pupil shapes. Standard as well as customized illumination modes can be enhanced by optimizing the polarization mode, to maximize the contrast and reducing the mask error factor per application.


Applications: Patterning at the 40nm node and below.

Platform: The TWINSCAN platform was introduced in 2000. The new XT:1900i is based on ASM's previous generations of immersion lithography systems. The XT:1900i uses the TWINSCAN platform's dual wafer stage functionality for parallel dry metrology and wet exposure to achieve a claimed 131 wafers per hour (125 exposures).It will be using the ‘Starlith' 1900i inline catadioptric lens system from Carl Zeiss SMT.

Availability: Mid 2007 onwards.