Light Source Innovations to Enhance Fab Productivity and Lower Cost of Ownership

As chipmakers continue to reduce feature sizes and shrink CDs on the wafer to meet customer needs, Cymer is developing light sources that enable advanced lithography, and introducing innovations to improve productivity, wafer yield, and cost of ownership. In 2008, the fifth generation of Cymer’s dual chamber ArF excimer laser, the XLR 540i was developed as the immersion light source solution for 45 nm patterning integrated with the Nikon NSR-S610C. This light source was the first to incorporate a new optical architecture using a regenerative amplification stage, rather than a double pass mode, known as Recirculating Ring Technology. XLR Ring Technology enables significant improvements in both performance and cost of ownership. In particular, the architecture allows dose control at the wafer plane which is 1.5x improved over the previous generation light source and provides improved spectral bandwidth stability, both of which enable superior CD control and wafer yield for the chipmaker. In addition, XLR technology reduces cost of ownership (CoO) by 20% by providing significant improvements in key module lifetimes. Further enhancements in productivity are provided by incorporating Gas Lifetime Extension (GLX™) to reduce the frequency of gas refills by up to 20x, directly leading to increased numbers of wafers produced daily.

The XLR 640ix is the next generation of argon fluoride (ArF) light sources, and the first to provide flexible power output to meet ever-increasing productivity demands, particularly for double patterning applications. It has the unique capability to operate in a range from 60 watts for typical immersion applications, to 90 watts for higher dose or higher throughput applications. This provides optimal flexibility for chipmakers’ current and future processes, as well as the ability to adjust power as needed for different process layers to save on operating costs. Cymer also incorporated special power optics at critical locations to improve module lifetimes, and increased pulse stretching to reduce the risk of damage to the scanner optics. Since the Ring architecture improves peak energy density homogeneity using its Power Ring Amplifier (PRA) chamber, the 640ix can achieve its 50% higher power output at the same peak beam energy density as prior generation 60W light sources. This is a key enabler for the use of 90W power output in production, and potentially higher deep ultraviolet (DUV) power levels in the future, with no added risk of damage to expensive lens elements. Table 1 summarizes the many productivity and cost of ownership advantages of the XLR 640ix light source.

The XLR 640ix also incorporates new controller technology, including Energy Timing Control (ETC) for large improvements in spectral bandwidth stability, energy dose stability, and additional wavelength stability. Figure 1 illustrates the marked improvement in E95% spectral stability achieved with the XLR 640ix as compared to the XLR 540i, even under changing duty cycle (DC) operating conditions. This translates to improved CD control and higher wafer yields.

Figure 1: XLR 640ix bandwidth stability is markedly improved compared to the XLR 540i.

Figure 2 shows the significant improvement in integrated energy dose stability (IEDS) enabled by the XLR 640ix as compared to the XLA 340. The Recirculating Ring Technology along with Energy Timing Control enables a 3x improvement in energy stability, which not only enables improved CD control, but also supports higher throughput scanner operation.

Figure 2. XLR 640ix Energy Dose Stability shows significant improvement compared to the XLA 340.

As process nodes continue to shrink, and our customers require increasing availability and cost effectiveness in our light sources, Cymer is committed to continually providing the source technology to meet these needs. The XLR 640ix is the current generation DUV light source and is compatible with the Nikon NSR-S620 scanner. If you have questions or would like additional information about Cymer light sources, please contact marketing@cymer.com.

Carl W. Steinbrecher — Sr. Business Manager
Mary Haviland — XL Product Line Key Product Manager
Cymer, Inc.