Nikon brings immersion into production
Mark LaPedus
EE Times
(02/16/2006 7:06 AM EST)
SAN JOSE, Calif. — Beating its rivals to the punch, Japan’s Nikon Corp. claimed to have shipped the world’s first production quality immersion lithography system in the market. The first tool has been reportedly shipped to Toshiba Corp., sources said.
Nikon’s tool, the NSR-S609B, is a 193-nm wavelength, immersion scanner said to have a numerical aperture (NA) projection lens of 1.07. Originally announced last summer, Nikon’s S609B is targeted for mass production of 55-nm memory products and development of 45-nm devices.
The company declined to identify the first customer for the machine, but sources said they believe that Toshiba obtained the scanner last month. Toshiba is reportedly looking at immersion lithography for use in producing NAND-based flash memories at the 55-nm node.
Some speculated that the tool is located in Toshiba’s 300-mm wafer fab joint venture in Japan. Earlier this month, Toshiba and its NAND development partner, SanDisk Corp., said they plan to boost the investment and production levels of the 300-mm fab venture in Yokkaichi, Japan. The fab venture is fabricating NAND memory using 90-nm processes. Toshiba plans to introduce a 70-nm process this month and then plans to introduce a 52-nm process by March 2007.
Meanwhile, Nikon’s announcement represents a major milestone in lithography. Not long ago, immersion was considered a novelty item at technical conferences. Now, the industry is looking at making a big transition from conventional 193-nm “dry” scanners to 193-nm immersion lithography for chip production at the 65-nm node and beyond.
Chartered, IBM, Samsung, TI, TSMC and others have immersion lithography on their respective roadmaps, analysts said. Intel Corp., however, claims that it will continue to use 193-nm “dry” scanners at the 45-nm node.
Still, the “Big Three” in the lithography industry — ASML Holding NV, Canon Inc. and Nikon — have separately been working on 193-nm immersion scanners for some time. ASML and Nikon were about dead even in the race, although the Japanese company now appears to have a slight edge.
ASML of the Netherlands will ship its first hyper NA tool, dubbed XT:1700, at the end of March, according to sources. The tool is said to have a 1.20 NA projection lens, although sources believe that the initial machines will be specified at 1.05 NA.
Nikon's new 1.07 NA machine is based on what it calls a Local Fill Technology and a Tandem Stage design. Nikon’s proprietary Local Fill Technology claims to eliminate scanner-induced immersion defects with no bubbles, water spots or backside wafer contamination. This technology also eliminates evaporation of the immersion fluid, providing a critical advantage in preventing immersion related overlay problems, according to Nikon.
To increase throughput, Nikon developed the Tandem Stage design that utilizes two stages with different functions to optimize the performance of the tool for immersion lithography. Overlay accuracy has been reduced to 7-nm or less with the Tandem Stage, according to Nikon. |
