The Nikon eReview: AMD (GlobalFoundries) Demonstrates Great Product Performance Using NSR-S610C

Discussing the current status of immersion performance and NSR-S610C production integration within AMD Dresden during LithoVision 2009, Dr. Harry Levinson, Senior Fellow and Manager of AMD’s Strategic Lithography Technology Department, reported that for 45 nm logic technology, immersion lithography could increase the k₁ factor from the 0.31 - 0.38 range to 0.40 and above, thereby avoiding many design rule restrictions.

Dr. Levinson reported that the NSR-S610C was introduced into AMD’s well-established 45 nm technology process, and announced that world-class focus and overlay data was achieved through close cooperation between Nikon Corporation and AMD. Following a variety of focus optimization efforts, across wafer focus 3 sigma = 24 nm was achieved, with mean focus stability < 10 nm. In addition, excellent lens heating control and field curvature/astigmatism performance were demonstrated.

Figure 1. World-class across wafer focus 3 sigma = 24 nm was achieved through close cooperation between Nikon Corporation and AMD.

Commenting on S610C overlay performance, Levinson noted that by minimizing environmental impacts, coupled with interferometer improvements and optimized airflow, 5 nm overlay residuals for contact to gate layers was achieved. When considering overlay matching across scanners from different vendors, Levinson highlighted that higher order overlay matching for both field and grid terms is vital. S610C grids were matched to the fab reference within < x = 7 nm and y = 6 nm, free of any systematic signatures. Since the overlay matching delta compared to dedicated machines is only 20% using same-vendor systems and 30% for mixed-vendor systems, Levinson announced that they can run the majority of critical layer combinations in a mixed-vendor mode.

Figure 2. S610C grids were matched to the fab reference within < x = 7 nm and y = 6 nm, free of any systematic signatures (left image). With this strong matching performance, AMD can run the majority of critical layers in mixed mode.

Levinson also provided an update on immersion defectivity, noting that the unguarded water film is quite challenging and requires a very robust nozzle design. He reported that the essential steps toward low defectivity performance included: use of materials with high dynamic receding contact angles, wafer edge/bevel fine-tuning, nozzle optimization and proper cleaning/nozzle flushing execution, as well as strong collaboration between Nikon and the customer. Collectively these factors enabled defectivity levels that justify S610C use in high-end production. Levinson wrapped up his informative presentation with product performance data, reporting that they have successfully run 45 nm lots on the S610C using their most critical contact and gate layers (which have large impact on yield, speed) and announced that they achieved good yield and great speed.

Figure 3. AMD has successfully run 45 nm lots on the S610C using their most critical contact and gate layers, achieving good yield and great speed.

In his conclusion, Levinson summarized that close cooperation between the two partner companies enabled world-class focus and overlay data, with defectivity levels acceptable for production, and reiterated that very good matching to their fab baseline was achieved. Together these attributes yielded great product performance on their most critical layers using the NSR-S610C immersion scanner.