Fire losses in U.S., European and Asian fabrication clean rooms are pushing the plastics, insurance, and semiconductor industries toward less-flammable polymers for tools, wet benches, ducts and wall and floor coverings.
An urgency pervades the drive to reduce plastics' flammability, because making plastics less flammable might be less expensive than potentially huge business-interruption losses at fabrication facilities, known as fabs.
At least 190 fab fires have occurred worldwide during the past 20 years, Vinni DeGiorgio, semiconductor coordinator with Norwood, Mass.-based Factory Mutual Engineering Association, said in a telephone interview.
``And there are probably five [fires] for every one we hear about,'' he estimated.
News reports in Asia said fires broke out at Advanced Microelectronic Products Inc. in Hsinchu, Taiwan, on Nov. 11; the joint venture United Integrated Circuits Corp., also in Hsinchu, on Oct. 3; Chartered Semiconductor Manufacturing Pte. Ltd. in Singapore on Sept. 26; Hana Microelectronics Public Co. Ltd. in Bangkok, Thailand, on Sept. 22; and Winbond Electronics Corp. in Hsinchu in October 1996.
The Advanced, United, Chartered and Winbond blazes damaged wafer fabrication facilities. The Hana fire started in a chemical laboratory and shut down integrated-circuit production. Recoveries ranged from days to months, and, in two cases, damage was in the hundreds of millions of dollars.
In an equipment breakthrough, Factory Mutual Research Corp., a unit of Factory Mutual Engineering, has developed a test apparatus to measure the capabilities of plastic products to resist fire and minimize emissions of smoke and corrosive byproducts.
Refined during 20 years, the device tests plastics' inherent properties and, when in use, should reduce chances for insured property losses at the fabs.
FMRC, also in Norwood, expects to market the device to independent testing and certification laboratories serving computer chip manufacturers, clean room users and third parties worldwide, for less than $100,000 per unit, said George Smith, construction and building materials section manager in the approvals division.
``We are looking at making combustible materials less combustible'' through this test apparatus, he said.
FMRC is contracting with Fire Testing Technology Ltd. of East Grinstead, England, to fabricate production quantities of the apparatus, mostly from off-the-shelf components. Some individually built early units have cleared industry scrutiny.
Clean rooms boom worldwide. Fab data specialist Strategic Marketing Associates of Soquel, Calif., said 996 fabrication facilities existed as of Dec. 31, 1996, and another 155 were being constructed in 1997 — 47 percent in Asia, 33 percent in North America and 20 percent in Europe.
A state-of-the-art fab can cost $1.2 billion to $1.5 billion, said George Burns, principal of Strategic Marketing. A less-sophisticated fab may cost $500 million. Equipment accounts for about 80 percent of the cost.
Three competing mutual insurance companies — Allendale Mutual of Johnston, R.I., Arkwright Boston of Waltham, Mass., and Protection Mutual of Park Ridge, Ill. — own or direct the Factory Mutual organizations and provide lead coverage on a substantial portion of the world's semiconductor fabs. FMRC is the insurers' research arm.
In September, FMRC published and began distributing a 21-page document that explains criteria for the plastics' flammability test protocol. Effective Oct. 1, Factory Mutual class number 4910 gives procedures to identify plastic materials that meet stringent limits on fire propagation, smoke and corrosion.
Michael Burke, vice president and chief engineer for Allendale Mutual Insurance Co., said in a news release: ``Over the next 24 months, virtually every [semiconductor industry] customer [of Allendale] will either be retrofitting high-tech, rapid-acting fire-suppression systems directly into plastic `tools' or benches, or will be installing tools which meet the very demanding [FM]4910 protocol. Such tools are judged virtually inherently safe for fire and require no protection.''
In early July, FMRC listed two materials that passed flammability test standards. The products are a modified rigid PVC from Takiron Co. Ltd. of Osaka, Japan, and a newly formulated fire-retardant polypropylene from Compression Polymers Group of Moosic, Pa.
Takiron produces engineered plastic materials for industrial, agricultural, electronics and medical markets and has annual sales of about $550 million.
Compression molder and sheet extruder Compression Polymers Group, a 1993 joint venture between Crane Plastics Co. of Columbus, Ohio, and the Keisling family's Compression Polymers business, has annual sales of about $75 million.
The resin and sheet suppliers ``may take a commercially acceptable resin and tweak the formulation with additives or fillers or blends'' to reduce fire and corrosion characteristics, Smith said.
FMRC has worked with resin suppliers, wet bench and tool manufacturers and chip makers to identify other eligible materials including four fluoropolymers: ethylene chlorotrifluoroethylene, polytetrafluoroethylene, perfluoroalkoxy and polyvinylidene fluoride.
Those materials are moving toward FM4910 listing. In addition to meeting the flammability requirements, the materials also must be weldable and be resistant to acids and alkalies.
In its early days, the semiconductor industry used rigid PVC in clean rooms. The material has good fire resistance, does not propagate and remains in wide use in Asia. Dioxin and smoke concerns drove out use of the material in the United States.
Standard PP appeared in U.S. clean rooms, but its quick combustibility was demonstrated about eight years ago. Next came development of nominal Underwriters Laboratories Inc. standard 94 V-0 fire-retardant PP, ``which turned out to be worse in real fire situations than unmodified PP,'' said Jerry Wagner, manager of polymer development for Compression Polymers.
Also, the fire-retardant PP became ``a significant source of potential process contamination from trace-metal leachables and organic leachables,'' Wagner said.