Everything You Wanted to Know About Halogen-free Printed Circuit Boards

Halogen-free PCB
Everything You Wanted to Know About Halogen-free Printed Circuit Boards

With increasing awareness about the side effects of leaded and halogen materials used in different electronic products, many world governments are imposing stringent laws and regulations to curb their use. As a result, the demand for environmentally-free electronic products has increased in recent years. Having said that, most of these products are driven by PCBs, built using halogen-free materials. Although in physical appearance, the halogen-free materials may look similar to regular PCB materials, their dissipation factor, dielectric constant, and moisture diffusivity largely differ. What are halogen-free PCBs? What are the popular applications of these PCBs? How they can add value to your application? Read this post to get answers to all questions that you may have regarding these PCBs.

Why is Halogen Toxic? 

Halogen elements are the Group 17 elements in the periodic table. Fluorine, chlorine, bromine, Atastatium, and iodine are the popular halogen elements known to us. These halogen elements are known for their fire retardant capabilities, which makes them an ideal choice for electronic applications where high temperatures may be involved. Most printed circuit boards that we use today are built using FR4 and CEM3 flame retardant materials, which feature halogens.

Many studies conducted across the world suggest that halogen-containing flame retardant materials are dangerous to human health and the environment. They emit toxic gases and release harmful byproducts into the air when burnt and both these can have severe consequences for humans. Bromine and chlorine exposure results in blurred vision, coughing, nausea, skin irritation, burning nose, eyes, and throat. Prolonged exposure to these halogens can be detrimental. As a result, the RoHS Directive published in July 2006 banned two most used halogenated flame retardants - polybrominated diphenyl ethers (PBDE) and polybrominated biphenyls (PBB). Other substances were added to this list in later years.

An Overview of Halogen-free PCBs and Their Benefits

A halogen-free PCB is a type of PCB made of copper-clad laminates with bromine (Br) and chlorine (Cl) content less than 0.09% weight ratio, as defined in the IPC/JEDEC J-STD-709 standard.

The PCBs made of halogen-free compounds offer several benefits over regular PCBs, which accounts for their increasing popularity in many applications. The following are a few advantages of halogen-free PCBs.

  • Halogen compounds are substituted by Nitrogen (N) and Phosphorous (P). This substitution reduces the molecular bond polarity in the epoxy resin, thus improving the breakdown voltage and insulation resistance of the PCB. This property contributes to its increasing use in TV/displays and power products.
  • Phosphorus and nitrogen content in halogen-free PCB is higher than standard printed circuit boards. This increases its Tg Value and monomer molecular weight, which contributes to its thermal stability.
  • Halogen-free boards possess better insulation properties than regular PCBs. Thus, they are used in various electronic products such as display screens, TVs, and other electronics that demand high insulation properties.
  • Halogen-free PCBs possess a low coefficient of expansion than regular PCBs. This is mainly due to the low molecular mobility of halogen molecules.
  • There are high manufacturing costs associated with electronic devices that are designed for high-frequency applications. This is where halogen-free PCBs can make a difference. Although these PCBs are expensive than standard FR4 PCBs, when their long-term performance is taken into the account, the costs may compensate. So, manufacturers can reduce their manufacturing costs by including halogen-free PCBs in their applications that will be regularly operated at high frequencies.
  • Halogen-free printed circuit boards do not release toxins or any harmful byproducts when disposed of. This helps reduce their environmental impact and confirms green protection requirements.
  • Compliance with green regulations and low disposal prices make these boards applicable across all markets.

Applications of Halogen-free PCBs

The PCBs made from halogen-free compounds are widely used in the following applications:

  • High-end computing
  • Servers
  • Mobile and wireless devices
  • Consumer electronic devices
  • Signaling devices
  • Transportation applications

Over the years, these printed circuit boards have become a common choice in power stations, substations, laboratories, distribution rooms, and so on. Halogen-free PCBs are expensive than conventional PCBs due to material designs, costs of materials, and complexities involved. Thus, you must source them from experienced manufacturers like Twisted Traces. The company provides leaded and RoHS-compliant and halogen-free PCBs for use in medical, consumer electronics, industrial electronics, municipal applications. All PCBs are entirely made in the company’s well-equipped facility at Elk Grove Village, Illinois and offer high-quality PCB fabrication. 

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