In order to meet the requirements of halogen-free PCB, the content of halogen contained in the PCB must not exceed a certain amount, which is measured in parts per million (ppm).
Halogens have a variety of uses in PCBs.
Chlorine can not only be used as a flame retardant or protective coating for PVC wire but also a solvent for semiconductor development and cleaning computer chips. Similarly, Bromine can be used as a flame retardant to protect electrical components or to sterilize components.
It should be noted that it is difficult to find a real halogen-free PCBs. There may be small amounts of halogens on the board or some compounds hidden in unexpected places. Following are examples.
(1) The green circuit board will not be halogen-free unless the green substrate is removed from the solder mask because the epoxy resin that helps protect the PCB may contain chlorine. The halogens may also be hidden in components such as glass adhesives, wetting agents and curing agents and resin accelerators.
(2) It should be paid attention to the potential pitifall of halogen-free materials. For example, the ratio of solder to flux will be affected in the absence of halogen, resulting in scratches.
However, such problems are unnecessary to be solved. A simple way to avoid scratches is to use solder resist to define the pad.
It is also important to cooperate with a reputable PCB manufacturer to ensure the transparency of the halogen content. Since not every manufacturer currently has the capability to produce these PCBs though they may have certifications. Nevertheless, the requirements to remove the halogen can be brought out since the place and use of the halogen are known. In one word, to work closely with the manufacturer is the best way to avoid unnecessary halogens.
Halogens do play a vital role in the structure of PCBs, but one disadvantage should not be ignored, the toxicity. Surely, they are functional flame retardants and biocides but they may cost a lot once something bad happen.
Chlorine and bromine are the main problems here. Exposure to either of the two chemicals may cause uncomfortable symptoms, such as nausea, coughing, skin irritation and blurred vision. However, even though correctly-treated halogen-containing PCBs is unlikely to be a dangerous exposure, the adverse side effects should be seen if a PCB catches fire and emits fumes.
If chlorine-containing components happen to mix with hydrocarbons, dioxins, a deadly carcinogen, thus can be produced. Unfortunately, some countries prefer to dispose of PCBs poorly because of the limited resources available to safely recover them. Therefore, the improper treating of PCB with high chlorine content is dangerous to the ecosystem. Burning them to eliminate (which does happen) may release dioxins into the air.
The main advantage is that they are less toxic alternatives to halogen-filled alternatives. The safety of your technicians and those who will handle the circuit board needs to be considered first.
In addition, the environmental risk is much lower compared to equipment containing a large amount of such hazardous chemicals. Especially in areas where the best PCB recycling practices are not available, a lower halogen content can ensure safer disposal.
In the booming technological era, consumers are becoming more aware of the toxins in their products, and their applications are almost limitless. Ideally, the automotive electronics, mobile phones and other devices that we maintain close contact with should be halogen-free.
However, reduced toxicity is not the only advantage: they also have advantages on performance. These PCBs can withstand high temperatures and are therefore very suitable for lead-free circuits. Since lead is another compound that most industries try to avoid, you can kill two birds with one stone.
Halogen-free PCB insulation materials may be low-cost and effective for disposable electronic products. Moreover, because of the low dielectric constant delivered by these circuit boards, it is easier to maintain signal integrity.
All of us should strive to raise awareness to limit avoidable hazards in important equipment such as PCBs. Although the law has not yet stipulated halogen-free PCBs, it represents that relevant organizations are working to phase out the use of these harmful compounds.
If you have questions about our halogen-free PCB production capacity, or the specifications required for your custom project are not listed on this page, please feel free to contact us. We will reply within one workday. We will continue to provide quotation support and design support. Welcome to learn about our production process.