Immersion and dry ArF scanners enabling 22nm HP production and beyond

摘要

Pattern shrinks using multiple patterning techniques will continue to the 22nm half pitch (HP) node and beyond. Thecutting-edge Nikon NSR-S621D immersion lithography tool, which builds upon the technology advancements of theNSR-S620D [1], was developed to satisfy the aggressive requirements for the 22 nm HP node and subsequent generations.The key design challenge for the S621D was to deliver further improvements to product overlay performance and CDuniformity, while also providing increased productivity. Since many different products are made within an ICmanufacturing facility, various wafer process-related issues, including the flatness or grid distortion of the processedwafers and exposure-induced heating had to be addressed. Upgrades and enhancements were made to the S620Dhardware and software systems to enable the S621D to minimize these process-related effects and deliver the necessaryscanner performance.To enable continued process technology advancements, in addition to pattern shrinks at the most critical layers,resolution for less critical layers must also be improved proportionally. As a result, increased demand for dry ArF insteadof KrF scanners is expected for less critical layers, and dry ArF tools are already being employed for some of theseapplications. Further, multiple patterning techniques, such as sidewall double patterning, actually enable use of dry ArFinstead of immersion scanners for some critical layers having relaxed pattern resolution requirements. However, in orderfor this to be successful, the ArF dry tool must deliver overlay performance that is comparable to the latest generationimmersion systems. Understanding these factors, an ArF dry scanner that has excellent overlay performance could beused effectively for critical layers and markedly improve cost of ownership (CoO).Therefore, Nikon has developed the NSR-S320F, a new dry ArF scanner also built upon the proven S620D Streamlignplatform. By incorporating the Streamlign innovations, sufficient overlay accuracy for critical layers, as well asmaximized productivity can be achieved. Furthermore, CoO will be significantly improved, which is the vital benefitwhen comparing ArF dry vs. immersion scanners.In this paper / presentation the latest S621D and S320F performance data will be introduced.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.