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Product Briefing Outline: Nikon has introduced the NSR-SF150, a scan field i-line stepper with extended high throughput and even lower claimed cost of ownership than previous i-line models. Throughput has been increased by more than 50 percent to 180 wafers per hour or more, while overlay was reduced by more than 30 percent over the previous model (NSR-SF140). The system makes use of leading-edge lens technology to achieve the same wide exposure field as DUV scanners, making it better for mix-and-match applications. SF150 can be used for sub-critical (180nm & above) layers in mass production of next-generation memory and microprocessors. Nikon will begin shipping systems in the second quarter of 2007.

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.