Current technologies are now anchoring towards green solutions, aiming for materials and processes with minimal impact on the environment. Likewise, in printed circuit boards or PCBs, there is increasing interest in recycling materials, designing and manufacturing electronic boards and materials that induce less harm to the environment. The establishment of ROHS or Restriction on Hazardous Substances standards has pushed PCB partners to eliminate lead, bromine and other toxic chemicals to abide by the policies and legislations. PCB suppliers that are already compliant with the prohibition of hazardous substances have a strong position in the industry, being able to cater to wide markets that are leaning towards green technology.
Halogens are considered a group of elements with unwanted effects on human health and the environment. Although not fully eliminated, halogens are slowly being eradicated to conform to international standards. We will explore more about halogen free PCBs, their key properties and necessary advantages in the world of electronics.
What is a Halogen-Free PCB?
A halogen free PCB is a type of PCB that does not use halogens in its manufacturing processes, making it a more environmentally friendly alternative than typical substrates. Halogens are the elements under Group 7A of the periodic table of elements. These elements include chlorine, bromine, iodine and astatine, which are highly reactive due to the presence of seven valence electrons on the outer layer of their molecular structure.
As printed circuit boards need to comply with international standards about flame retardancy ratings, halogens such as bromine and chlorine are used in PCB manufacturing. These halogens release free radicals that interfere with combustion processes. Despite their key advantages and contribution to the flame-retardant properties of PCBs, halogens are considered hazardous substances due to their toxicity. When heated, halogenated PCBs can release harmful chemicals, posing health and environmental risks. During thermal degradation, halogenated PCBs produce furan and dioxin, which are both undesirable substances.
What are the Properties of Halogen-Free PCB?
To understand further, below are the distinct properties that make halogen free PCB a wise option in electronics manufacturing.
- High Insulation. Halogen Free PCB meets the required insulation requirements of PCB laminates. This characteristic is crucial in ensuring that the dielectric PCB can avoid electrical conduction.
- Flame Retardance. Halogen free PCBs use substitute chemicals to add flame-retardant properties to the substrate. There are various types of halogen-free flame retardants that are used as alternatives, such as phosphorus compounds and nitrogen-based flame retardants and metal hydroxides. Halogen free PCBs are deemed to meet UL standards with their self-extinguishing capabilities.
- Low Coefficient of Thermal Expansion. Halogen free PCBs have a lower coefficient of thermal expansion or CTE which translates to lower expansion during thermal variations. This type of PCB is also able to withstand extreme heat while operating consistently in high temperatures. This needs to be highlighted since PCBs go through a lot of heating processes, such as during soldering and application.
- Good Mechanical Strength. Since laminates provide structural support to components, halogen free PCBs exhibit good mechanical strength, resisting opposing stresses that can influence the PCB. They also possess comparable peel strength to conventional FR4 substrates, which is suitable for composite materials resisting delamination defects.
What are the Advantages of Halogen-Free PCB?
Listed below are the key advantages that make halogen free PCBs stand out from other traditional rigid PCBs.
- Compliance with Standards. The absence of halogens during the manufacturing of halogen free PCBs eliminates the possibility of releasing harmful substances to the environment. Many end customers prefer manufacturers and suppliers that comply with international standards, as this signifies attention to quality and a narrowed focus on world-class products and services.
- Good Thermal Stability. For applications needing to generate power and heat, halogen free PCBs can meet high temperature requirements. As some materials may behave adversely with the application of heat, halogen-free PCBs are formulated to withstand extreme temperatures without going through decomposition.
- Enhanced Electrical Performance. Halogen free PCBs can carry high frequencies without signal integrity issues due to their excellent dielectric properties. This unique substrate provides sufficient electrical insulation, eliminating risks for short circuits. It can also perform consistently over long operating ranges, at varied stresses and temperatures.
- Environmental Friendliness. Developing halogen free PCB solutions is a long-term and forward-looking approach in the industry. It is a well-known, safer and more sustainable material that has a minimal effect on health and the environment, especially when disposed of or incinerated. A manufacturer that adapts to this innovation in material is positioned to invite more sales from diverse markets.
What are the Applications of Halogen-Free PCB?
The widespread promotion of sustainability in manufacturing in many areas of electronics has led to the vast use of halogen free PCBs in the following applications.
- Automotive. The automotive market segment is also driving for electronic devices with minimal impact on the environment. The integration of advanced driver assistance systems (ADAS) in vehicles has boosted the manufacturing of parts and PCBs that are processed and assembled with less dependence on halogens and lead-based substances. Halogen free PCBs can meet the stringent requirements of automotive standards while being compliant with environmental standards.
- Consumer Electronics. With the abundance of consumer electronics such as mobile phones, tablets, and computers is a growing interest in recycling PCB materials. This sustainable approach can be difficult if the materials to be extracted consist of toxic chemicals. Using halogen free PCBs contributes to proper management of e-waste and more effective handling of recycled materials.
- Medical. Since medical devices are even closer to the end-user than other types of devices, halogen free PCBs provide the advantage of safe materials, especially when utilised by patients and healthcare providers. These PCB types can be used in diagnostic equipment, health tracking wearables and other patient monitoring systems.
Conclusion
Halogen free PCB is a PCB produced in accordance with current international standards. Qualified manufacturers must adhere to halogen-free national standards during manufacturing. Otherwise, it may pose a threat to the environment and human health. With the advancement of industrialisation, the concept of halogen free has penetrated into the PCB industry. Manufacturers who follow this standard will produce PCBs with better performance in all aspects. Thus, better industrial electronic products can be manufactured.
