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Product Briefing Outline: Sokudo has launched its new RF3S coat/develop track system that delivers the technology and productivity requirements of 45nm-and-beyond immersion and dry lithography. The RF3S provides less than 0.8nm 3 sigma critical dimension (CD) uniformity and immersion defect density of less than 0.1 defects/cm², according to the company.

Problem: Tighter CD control is required for devices at 45nm and below as lithography systems are being pushed to the limits of acceptable resolution tolerances. With immersion lithography systems, the key challenge is minimizing the yield impact of waterborne defects after exposure while being able to match increased wafer throughput of lithography tools in an effort to minimize the cost of ownership.

Solution: To provide expected CD uniformity, the RF3S offers both biased heater and isothermal technology, depending on the application. Biased hot plate technology incorporates independently-controlled heater zones to precisely control temperature across the wafer, enabling optimized CD uniformity for post-lithography or etch. The system's isothermal solution uses Sokudo's proven Rapid Hot Plate (RHP) design for uniform plate temperature without the need for tuning to achieve uniform CD, with an option that adjusts for wafer warpage. Key to the RF3S system's 180 wph is its flexible coat cell design that allows up to four spin coat modules and up to six SDC (Sokudo Defect Clean) Soak modules. The SDC Soak modules, which utilize wafer-cleaning technology from Dainippon Screen, remove defects before and after immersion exposure. The system's new ECO nozzle is claimed to shorten develop time by more than 60 percent, while a faster transfer robot, a faster exposure system interface and reductions in module overhead time decrease wafer handling time and increase system throughput by a claimed 20 percent.

Applications: Immersion and advanced dry lithography processing

Platform: The RF3S employs integrated tool monitoring and diagnostics using Applied Materials' NeXus real-time SPC (statistical process control) tool to perform split-second analysis of system conditions and immediately spotlight and monitor changes. The system also offers multiple options for integrated optical CD metrology for process monitoring.

Availability: July 2007 onwards.