Factory Mutual, Sematech join forces to study cleanroom plastics
By Tammy Wright
Norwood, MA — Factory Mutual Research Corp. (FMRC) and Semiconductor Manufacturing Technology (Sematech) are teaming up to provide chipmakers with safer materials to use in their cleanroom environments. The organizations are conducting a study that could expand the number of choices available to include materials that are resistant to fire, more durable and potentially less contaminating.
Sematech has contracted FMRC to examine whether or not newly developed plastics with low combustibility are compatible with computer chip manufacturing processes.
“People are concerned with the compatibility of new materials, and it`s a stumbling block for the semiconductor industry,” explains Heron Peterkin, a semiconductor engineering specialist at FMRC. “This project compares the process compatibility of materials used now with Class 4910 plastics.”
According to Peterkin, FMRC developed the Class 4910 protocol, which is the only available test standard for evaluating the flame, smoke and corrosion parameters of cleanroom materials. He says plastics that conform to the protocol are non-propagating, meaning that they burn only in the ignition zone.
“These materials .are difficult to catch on fire. They will burn in the area you put the flame to, but once you remove the flame, they will stop burning,” Peterkin adds. “They don`t propagate fire.”
The study will compare three existing materials — polypropylene (PP), fire-retardant polypropylene (FRPP) and polyvinyl chloride (PVC) — with three protocol materials: polyvinylidene fluoride (PVDF), chlorinated polyvinyl chloride (CPVC) and ethylenechlorotrifluoroethylene (ECTFE), more commonly known as Halar.
Both existing and proposed protocol materials will be tested for outgassing, chemical resistance and leaching. The existing materials will serve as the baseline for identifying contamination parameters.
For example, Peterkin says when materials are subjected to outgassing tests, a certain amount of material comes off as vapors, which can contaminate manufacturing processes. In the same way, leaching of ions and cations using purified water and extraction of ions and cations by chemicals can also contaminate manufacturing processes. FMRC plans to measure the effects of these tests in units of micrograms per square centimeter and then compare the findings in both material groups.
“Sematech will use the information to develop standards or contamination parameters for the semiconductor industry,” says Peterkin. FMRC, which is primarily known for its research on fire-induced contamination, also plans to use the data to enhance its 4910 protocol.
He believes the project will show that the protocol plastic materials are both fire-resistant and do not contaminate more than the plastics now in use.
Sematech says the study was commissioned to benefit the industry-at-large and serve the best interests of its worldwide membership.
“Sematech is not a clearing house for materials. We`re not promoting anyone`s product. We`re showing a methodology for determining chemical contamination indices for materials for cleanroom use,” explains project leader Dr. Avtar Jassal, who works in the environmental safety and health trust of International Sematech.
Results of the study will be released at a meeting to be held in November at Sematech`s headquarters in Austin, TX. The organization plans to invite and solicit comments from key plastic material suppliers and equipment manufacturers. CR