Major step-and-scan tool makers originally announced full-field, 157-nm scanners more than several years ago, and they promised to ship these systems in 2002 or 2003. But in the spring of last year, vendors were hit with a series of technical problems in 157-nm wavelength lithography, causing them to push out product shipments until late-2004 or early-2005, according to analysts.

Some experts even fear that 157-nm technology may drift out into late-2005 or later, prompting many chip manufacturers to work on contingency plans that will extend the use of 193-nm scanners with the help of resolution-enhancement and "subwavelength" techniques, such as phase-shifting photomasks or optical proximity correction (OPC).

One of the major concern still facing 157-nm lithography is a problem called intrinsic birefringence, which can exist in the calcium-fluoride (CaF2) lens material. Shortages of lens materials and resist problems also present major headaches for tools makers and their customers.

And the price tag for 157-nm tools is also a huge concern with some industry estimates placing the cost of those scanners as high as $25 million per unit when they begin to hit the market later this decade.

At the SPIE conference, the "Big 3" lithography suppliers--ASML, Canon, and Nikon--separately insisted that they have now overcome many of the technical problems and they each outlined their new and improved 157-nm plans on Thursday.

For example, Japan's Nikon Corp. hopes to ship a 157-nm tool, which will process chips at the 65-nm technology node with binary photomasks and at the 55- and 35-nm nodes using phase-shifting masks, according to the company.

Nikon's tool is a 4x reduction system featuring a high numerical aperture of 0.85 and a 22-mm image field, said Naomasa Shiraishi, staff engineer at the Tokyo-based company.

The scanner makes use of an advanced catadioptric lens, he said during his presentation at SPIE. Nikon plans to build two versions of the lens, including a plane and concave mirror configurations, he explained. The company expects to ship a production-worthy, 157-nm tool in the second half of 2004, according to the Nikon staff engineer.

Meanwhile, Japan's Canon Inc. is developing the FS1, a 157-nm for processing chips at 65-nm and below, said Hideki Nogawa, a representative for the Toyko-based company.

Canon's FS1 features a high NA of 0.8 and has a 22- x 26-mm field size," he told a session at the SPIE conference. Based on the company's FPA-5000 platform, the scanner makes use of an advanced catadioptric lens.

The lens makes use of "countermeasures' to combat intrinsic birefringence, Nogawa said. Production tools are expected in late 2004 or early 2005, according to the company.

Not to be outdone, ASML Holding N.V. of the Netherlands is working on two 157-nm tools. The first, dubbed the Micrascan VII, is a small-field tool for development purposes. The system is being developed by ASML's Silicon Valley Group unit in the United States.

ASML's production-worthy, 157-nm tool is based on the company's Twinscan architecture, a platform used in its 200-mm and 300-mm scanners. The tool is a 4x reduction system that features a high NA of 0.8, said Jan Mulkens, a representive of ASML who made the presentation at SPIE.

AMSL did not disclose the shipment date, but analysts expect the unit will be delivered by the end of 2004 or early 2005.