Results from the IPC/Intel Halogen Free Symposium
by Fern Abrams
Feb 22, 2008
Industry leaders respond to halogen free concerns
Recent announcements by major computer manufacturers Dell, HP, Lenovo, Apple and Intel about intentions to go bromine-free in the next two years were enough to ensure broad representation from the supply chain at January's IPC/Intel Halogen Free Symposium. More than 250 attendees gathered to share ideas and concerns regarding halogen-free electronics.
Although halogen free is the latest green trend to be embraced by the industry, speakers made clear that its environmental bona fides were all but clear. Although some brominated flame retardants (BFRs) have been shown to be hazardous, it has not been proven that all BFRs share hazardous properties. To date, only polybrominated biphenyls (PBBs) and Penta- and Octa-Polybrominated Diphenyl Ether (penta- and octa-PBDE) have been restricted by regulations. Further, as pointed out by both IPC and EPA speakers, significantly less data is available regarding the safety and environmental issues that may be associated with the substitutes. In fact, TBBPA, the compound used in 95 percent of circuit boards today, has been shown safe by a comprehensive European Union (EU) risk assessment.
Still, environmental groups continue to target BFR use, leading the industry to yield to the pressure by announcing target deadlines for BFR removal. IPC raised concerns that instituting substance bans without scientific justification is bad public policy and business practice. Nonetheless, IPC, as an industry trade association, is committed to supporting industry needs, including low halogen standards and education.
Other environmental concerns about the use of BFRs, PVCs, and other chlorine and bromine compounds in electronics relate to dioxin formation during low-temperature, incomplete combustion of hydrocarbons in the presence of bromine and chlorine. This can occur during accidental fires or, more commonly, improper recycling activities by developing countries.
While halogen-free laminate materials are available, they are more expensive. However, OEMs seemed unconcerned with this issue, as all of their competitors would be facing the same price issues for halogen-free or low-halogen products. Halogen-free laminates may offer some improved performance factors, including higher thermal reliability than conventional FR4 and some halogen-free resin systems, Df is lower than conventional FR4 and suitable for high-speed, low-loss applications without going for real low-loss material.
Other members of the supply chain raised concerns regarding the timing of a shift to low-halogen materials. Concerns were also raised regarding the introduction of new low-halogen materials so quickly on the heels of the lead-free materials changes.
According to speakers from the flip chip manufacturing set, the solder alloy is the more substantive change. Therefore, the dielectrics must be tailored to meet the demands of the solder.
One major area of concern in the supply chain is in regards to connectors. Nylon and Polybutylene Terephtalate (PBT), which are widely used in the connector industry, require the addition of Bromine and chlorine-based flame retardants to meet UL94-V0 flammability rating requirements. According to a speaker from the connector industry, changing plastics in a connector product is not trivial because of varying shrink rates among substitutes. Mold modifications typically required, and design changes not uncommon, requiring product testing and re-qualification. While in the past manufacturers turned to higher-cost plastic, such as liquid crystal polymers, to produce halogen-free connectors, within the past 18 months several plastic manufacturers have begun to introduce halogen-free versions of other resins, particularly nylon. These are currently being evaluated for manufacturability and performance.
Many attendees emphasized the importance of developing industry standards and test methods for halogen-free or low-halogen electronics as soon as possible. Committee Co-chair Scott O'Connell of Dell, reported on the progress of the IPC/JEDEC 4-33a committee and announced that the committee would hold a meeting the day after the symposium to continue work on a standard for low halogen electronics (J-STD-709). An open meeting will be held on Monday, March 31, during the IPC tradeshows in Las Vegas to present the draft standard prior to balloting.
Conference proceedings are available on CD at www.ipc.org/onlinestore. More information on the committee meeting on March 31 is available at www.GoIPCShows.org under standards development meetings.