The potential health risks associated with elevated concentrations of fluorine and chlorine in circuit boards led to the development of halogen free PCBs by the IEC. Given that electronics frequently incorporate materials with significant halogen content, achieving a halogen-free PCB entails minimizing the utilization of these substances or seeking suitable replacements. The level of halogen freedom in your PCB circuits should be determined based on your specific requirements and priorities.
A Halogen-free PCB is a type of circuit board that is manufactured without the use of halogen-containing materials, specifically halogenated flame retardants. Halogens are a group of chemical elements that include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). In the context of electronics manufacturing, halogens are often used as flame retardants in materials like PCB substrates, solder masks, and other components.
Standards such as IEC 61249-2-21 and JPCA-ES-01-2003 specify that halogen-free copper clads should have chlorine and bromine levels below 0.09 wt% (900ppm) and their combined total under 0.15 wt% (1500ppm). Thus, halogen-free PCBs are boards with chlorine below 0.09 wt% (900ppm), bromine below 0.09 wt% (900ppm), and overall halogens below 0.15 wt% (1500ppm).
Halogen free PCBs offer several key advantages compared to traditional PCBs that use halogen-containing materials. These advantages make halogen-free PCBs a preferable choice, especially in environmentally conscious and regulatory-driven industries. Here are some of the significant benefits:
Several common substrate materials are used in halogen-free PCBs. These materials provide the foundation for the PCB and play a crucial role in determining the board’s performance, reliability, and overall environmental impact. Here are some commonly used halogen-free substrate materials:
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The benefits of adopting halogen-free boards do bring about increased complexity, not only in the manufacturing phase but also in the design process. A prime example lies in the use of halogen-free solder and flux, which can occasionally result in issues like solder graping. This phenomenon occurs when the solder conglomerates into a single large blob instead of being evenly distributed across a connection. To counteract this challenge, a strategic design approach involves leveraging solder mask technology to precisely define the pad. This containment method helps manage the solder paste and reduces the likelihood of defects.
Working with novel materials presents its unique design idiosyncrasies, necessitating effective communication with manufacturers or thorough research before their implementation. Although halogen-free boards are gradually becoming more available, they are still relatively uncommon. It’s essential to engage in dialogue with your PCB manufacturer to ascertain their capability to produce PCBs using halogen-free materials.
As time progresses, our growing awareness reveals that many everyday materials harbor potential health risks. This awareness underscores the importance of standards, such as those developed by organizations like the IEC, for halogen-free boards. Understanding the typical sources of halogens (such as BFRs, solvents, and insulation) enables us to identify the elements to replace when transitioning to halogen-free solutions. Different standards permit varying halogen levels and may or may not detect specific types. Thorough preliminary research helps identify potential issues on your PCB. After pinpointing the desired materials, collaborating with the manufacturer and your CM (contract manufacturer) is essential to chart the most effective path forward. This might involve tweaking designs or refining specific manufacturing steps to ensure a successful PCB outcome.
Halogen-free PCBs are versatile and suitable for a wide range of industries that utilize electronic PCB boards, spanning from consumer electronics to industrial automation. Notably, they find significant application in the automotive and mobile phone sectors. While specifications may differ, consulting your manufacturer regarding industry-specific requirements is essential.
These boards are favored by companies demonstrating environmental responsibility, aiming to minimize their carbon footprint and reduce the release of toxins during production. Although halogen-free PCBs can benefit any company, they are particularly prevalent among those committed to sustainability.
If you’re considering halogen-free boards for your application but have concerns about compatibility, feel free to reach out to us. Our PCB experts are ready to discuss the distinctions between halogen-free PCBs and traditional boards and how these distinctions may impact your specific product.
