NEWS OF THE WEEK TECHNOLOGY
CLEANER CHEMISTRY FOR CLEANER CHIPS Supercritical C 0 2 is latest technique for stripping semiconductor wafers
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N E W H O M E Air Products will install a C0 2 cleaning machine at its research labs in Allentown, Pa.
DD A NEW USE—SEMICON-
ductor cleaning—to the many emerging industrial applications for supercritical car bon dioxide. C 0 2 producer Air Products & Chemicals and SC Fluids, a pri vate equipment maker in Nashua, N.H., have teamed up to com plete the development of super critical C 0 2 as a photoresist stripping agent for semiconduc tor wafers. Air Products says it will bring its experience in the supply deliv ery, and storage of high-pressure, high-purity bulk gases to the semiconductor industry As part of the agreement, Air Products
will install one of SC Fluids' cleaning machines at its R&D facility in Allentown, Pa. Supercritical C 0 2 is a strong solvent that has been used for years in applications such as caf feine and hops extraction. But its "green" nature is giving rise to novel new uses in, for example, chemical synthesis and dry clean ing (C&EN, July 16, page 27). David Mount, SC Fluids' vice president of strategic develop ment, says C 0 2 offers environ mental and cost benefits to the semiconductor industry, but that they are actually secondary The main driver in electronics, ac cording to Mount, is that exist-
CLEANUP
Superfund Collects $212 Million number of companies have agreed to pay $212 million for Superfund site cleanups in New Jersey and Texas. Under a consent decree with EPA and the Justice Department, Ciba Specialty Chemicals and Novartis will spend $92 million for soil cleanup at the 1,400-acre Toms River, N.J., site. CibaGeigy, the predecessor to the two firms, had at one time employed 975 people at the site and manufactured dyes, plastics, and plastic additives. Although no studies have shown a direct cause-effect relationship, area residents have long suspected the site as the source of a cluster of cancer cases in children. In
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1992, Ciba-Geigy agreed to pay $62 million to settle a seven-year environmental dispute with the State of New Jersey over the dumping of toxic wastes. Acting Assistant Attorney General John C. Cruden says, "This settlement shows that we can resolve environmental law suits in ways that benefit not just the environment but the
communities that have been affected by the sloppy waste disposal practices of the past." In a second consent agree ment, a group of oil refiners and chemical companies agreed to pay $120 million to reimburse the Superfund pro gram for costs incurred to clean up the Sikes Disposal Pits near Crosby, Texas.— MARC REISCH
COSTLY Ciba-Geigy's two offspring will pay $92 million for cleanup of its Toms River, N.J., manufacturing site.
ing wet-chemical stripping tech niques are reaching their theo retical limits as circuit line archi tecture gets smaller and smaller. "We think that at 0.18 μηι and below, wet chemistry just won't clean these things out because of surface tension and capillary force," he says. Supercritical C 0 2 , on the other hand, has "zero surface ten sion," he says. "There are no fea tures we cannot wet." SC Fluids has a development relationship with IBM and last week shipped a "beta" version of its cleaning machine to IBM's research complex in East Fishkill, Ν . Υ. It's also working with ATMI, a top supplier of specialty materials and equipment to the semiconductor industry At least one other company— Supercritical Systems of Fre mont, Calif—is pursuing C 0 2 technology as well. Last year, it formed a joint development ven ture with Praxair, one ofAir Prod ucts' industrial gases rivals; soon after, it was acquired by Tokyo Electron Ltd., a big semiconduc tor equipment company Supercritical Systems Presi dent Max Biberger says the com pany continues to actively ad vance its technology and equip ment. However, he says it isn't providing progress updates "until the product is ready" Providers of conventional cleaning chemicals are watching intently Dana Durham, director of Ashland Specialty Chemical's ACT unit, a leading supplier of photoresist strippers, acknowl edges that the new technology could be a threat. However, he points out that the new machines both rely on traditional chemicals to do the cleaning job effectively A month ago, Durham says, Ashland launched an agreement with a semiconductor equipment supplier aimed at developing chemistry that will work with C 0 2 systems. " C 0 2 technology is not proven, but if it's successful, we want to be one of the first players," h e says. —MICHAEL MCCOY
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C&EN
/ SEPTEMBER
17, 2001
HTTP://PUBS.ACS.ORG/CEN
