Problem: With the continued increase in the number of non-critical layers for advanced ICs, the need to provide higher throughput lithography tools to lower fabrication costs grows. The high cost of DUV tools has led to improved tool designs to tackle throughput and overall performance while less effort had been given to non-critical i-line steppers.

Solution: The SF150 is the sixth generation scan field (SF) stepper from Nikon. The SF150 is designed to offer improved levels of productivity and cost of ownership, compared to previous production tools. The new wafer exchange system with optimized load/unload positioning reduces exchange times by 60 percent, while the lightweight, high acceleration wafer stage reduces stepping time by nearly a third, according to the company. In addition, alignment times are said to be cut in half using a new alignment processing system. These design enhancements enable the system to deliver a claimed 180 wafers per hour and have reduced cost of ownership by 25 percent compared to the previous SF model.

Applications: Sub-critical layers for mix-and-match applications.

Platform: The system incorporates Nikon's new ‘Skyhook Technology' to reduce vibration, plus optimized airflow and temperature control to improve lens stability and accuracy. The new SF150 stage design provides enhanced positioning control and enables six degrees of freedom for wafer stage control to further enhance overlay performance. The SF150 also incorporates the same advanced alignment system that is used in advanced Nikon scanners. The system delivers overlay accuracy of 25nm or less, exceeding the requirements for today's sub-critical layers, according to the company.

Availability: Second quarter of 2007 onwards.