A PCB fabricator recently asked if we wanted to specify halogen-free materials. Until now, we haven’t had to consider this in our designs, but I’m starting to wonder if a broader industry shift—similar to the lead-free transition years ago—is underway.
Are other designers or manufacturers here already specifying halogen-free laminates, perhaps following IPC/JEDEC J-STD-709? If so, how has this impacted board and assembly costs?
There is an increase in the use of halogen-free resin systems and the industry will probably move more in this direction over time. The selection of halogen-free materials used to be quite limited but now the laminate manufacturers are offering a much broader range of products so this is a good indicator of what’s taking place. Manufacturers that want to be fully RoHS compliant are specifying Halogen-free materials. Right now halogen-free laminate is more expensive – estimate around 15% to 20% - but might come down as its use increases. Shouldn’t effect assembly costs.
Worth noting that halogens serve as flame retardants in PCBs, so there’s a safety angle to consider. There have been cases of PCB fires even in UL-approved products with halogenated materials. When moving to halogen-free options, ensuring equivalent flame-retardant properties is critical, especially for high-power applications.
Halogen-free laminates typically substitute brominated/chlorinated flame retardants with phosphorus- or nitrogen-based compounds. This not only reduces toxic gas emissions during combustion, but often improves properties like glass transition temperature (Tg), insulation resistance, and thermal expansion. However, these materials can also come with slightly different dielectric constants and thermal conductivities, which may affect high-speed designs. It’s worth reviewing these characteristics carefully to ensure compatibility with your performance and reliability goals.
In my experience, the best protection is still solid design that prevents fault conditions from escalating in the first place. I’ve only encountered one instance where a PCB actually caught fire, and while halogen-based retardants helped slow it down, the real fix came from redesigning to eliminate the root cause.
As long as halogen-free materials are paired with equivalent flame retardants, and the design avoids scenarios like overloaded traces acting as fuses, they can be a safe and forward-looking choice. Preventing ignition conditions altogether should be the priority, regardless of the laminate.
Most halogen-free PCBs today rely on phosphorus- or phosphorus-nitrogen-based flame retardants. These work by forming a protective char layer or releasing non-combustible gases during combustion, which slows flame spread. While the chemistry is effective, it’s worth checking if these materials affect your process temperatures or resin behavior during lamination. Some can influence flow characteristics or require slightly different handling in manufacturing.