World Class Halogen Free PCB Manufacturer in China

PCBMay is a Professional Halogen Free PCB Boards Manufacturer in China,Who Provides Many Different Kinds of Halogen Free Boards.

Halogen Free PCB Background

Halogen free PCB substrates have been commercialized since 1998, the first in the world. A halogen-free board is a printed board that does not use halogen elements.By using a halogen material for the printed circuit board,it is possible to obtain characteristics such as flame retardancy and low warp resistance and therefore manufacturing is facilitated.

Why PCB Manufacturers Avoid Halogen in PCB Manufacturing?

However,a substrate using a halogen element produces dioxin when burned. For this reason,halogen-free has long been called for,but due to the difficulty of manufacturing,many manufacturers have not fully adopted it,especially for products with high component mounting density.

For a long time,brominated flame retardants have been used in the manufacture of printed circuit boards.Although Halogen free PCB suppliers have developed some halogen-free alternatives. The impact of these alternatives on the assembly process is still uncertain.

 Since the introduction of halogen-free,although halogen-free materials have occupied 10% of the laminate market.The industry still lacks the production experience to define the assembly process and reliability window.

Halogen-free PCB: Brief Introduction and Basic Concepts

If you have heard of the term “halogen-free PCB” and want to learn more, you have come to the right place. We share the story behind this printed circuit board.

Find out the facts about halogens in PCBs, halogens in general and the requirements for the term “halogen-free “. We also studied the advantages of halogen-free.

What is Halogen-free PCB?

In order to meet the requirements of halogen-free PCB, the content of halogen contained in the circuit board must not exceed a certain amount, and its content is in parts per million (ppm).

Halogens in PCBs

Halogens have many uses in relation to PCBs.

Chlorine is used as a flame retardant or protective coating for polyvinyl chloride (PVC) wires. It is also used as a solvent for semiconductor development or cleaning computer chips.

Bromine can be used as a flame retardant to protect electrical components or sterilize components.

What Level is Considered Halogen-free?

The International Electrochemical Commission ( IEC ) has set the standard to a total halogen content of 1,500 ppm by restricting the use of halogens . The limits for chlorine and bromine are both 900 ppm .

If you comply with the Restriction of Hazardous Substances ( RoHS ), the ppm limit is the same.

Please note that there are various halogen standards on the market. Since halogen-free production is not a legal requirement, the allowable levels set by independent entities (such as manufacturers) may vary.

Halogen-free PCB Board Design

At this point, we should note that it is difficult to find a real halogen-free PCB. There may be a small amount of halogen on the circuit board, and these compounds may be hidden in unexpected places.

Let us elaborate some examples. Unless the green substrate is removed from the solder mask, the green circuit board is not halogen-free.

The epoxy resin that helps protect the PCB may contain chlorine. Halogens may also be hidden in ingredients such as glass glue, wetting and curing agents, and resin accelerators.

You should also be aware of the potential pitfalls of using halogen-free materials. For example, in the absence of halogen, the ratio of solder to flux will be affected, resulting in scratches.

Keep in mind that such problems do not necessarily have to be overcome. A simple way to avoid scratches is to use solder resist (also called solder resist) to define the pad.

It is very important to cooperate with famous PCB manufacturers to ensure the transparency of the halogen content in the PCB. Although they are recognized, not every manufacturer currently has the ability to produce these circuit boards.

Nonetheless, now that you know the location of halogens and their purpose, you can specify the requirements. You may need to work closely with the manufacturer to determine the best way to avoid unnecessary halogens.

Although obtaining a 100 % halogen-free PCB may be a challenge, you can still manufacture PCBs with acceptable levels in accordance with IEC and RoHS regulations.

Why Create a Halogen-free PCB?

Although halogens play a vital role in the structure of PCBs, they have a disadvantage that is hard to ignore: toxicity. Yes, these substances are functional flame retardants and bactericides, but their cost is high.

Chlorine and bromine are the culprits here. Exposure to any of these chemicals may cause uncomfortable symptoms such as nausea, coughing, skin irritation and blurred vision.

Hazardous exposure is unlikely to occur when handling halogen-containing PCBs. Nevertheless, if the PCB catches fire and emits smoke, you can expect these adverse side effects.

If chlorine-containing ingredients happen to be mixed with hydrocarbons, it will produce dioxins, a deadly carcinogen. Unfortunately, due to the limited resources that can safely recycle PCBs, some countries tend to conduct poor disposal.

Therefore, improper handling of PCBs with high chlorine content is dangerous to the ecosystem. Burning these gadgets to eliminate them (which does happen) may release dioxins into the environment

The World goes Green – Why are Halogen-free Base Materials the Better Solution When the PCB Requirements are High?

The European history of halogen-free materials is a long and not always successful one. The first attempts to separate from the TBBPA as a flame retardant were made in the early 1990s.

According to IEC 61249-2-21: Definition of “halogen-free” the following applies:

  • Maximum 900 ppm chlorine
  • Maximum 900 ppm bromine
  • Total maximum 1500 ppm halogen

This means that halogen-free materials mainly use phosphorus, nitrogen and ATH as halogen-free flame retardants.

Today, modern base materials are classified according to the following UL classification, which also expresses the fact that the base material is different in the standardization.

FR 4.0 – filled and unfilled epoxy resin systems Tg 135 – 200 TBBPA.

FR 4.1 – filled and unfilled epoxy resin systems Tg 135 – 200 halogen-free

A new additional classification has been made for two years:

FR 15.0 – filled epoxy resin systems TBBPA RTI 150 ° C

FR 15.1 – filled epoxy resin systems halogen-free RTI 150 ° C

The replacement of the flame retardant TBBPA with halogen-free flame retardants is associated with other chemical properties of the resin systems. The bonding energy of the resin system increases significantly and serves as the basis for the improved thermal properties of the halogen-free materials. This increased bonding energy also improves the problem of adhesion to the glass fabric, which in turn has a positive effect on CAF performance.

In the lecture, various examples of the improved properties such as heat stability and CAF behavior in small HW-HW will be shown, which have been proven in practice.

Alternative “Green” Printed Circuit Boards: Halogen-free, Flame-retardant Printed Circuit Boards

Almost 77% of the printed circuit boards manufactured in Europe contain substances which, if burned, lead to substances that are hazardous to health. Manufacturing processes with polysiloxane are ecologically acceptable solutions because they do not emit any dangerous substances and they hardly pollute the environment.

So far, only three halogen-free, flame-retardant printed circuit boards have been economically implemented by manufacturers, but they require flame retardants containing phosphorus and nitrogen in order to meet the UL regulations on fire protection. Of these, in turn, only one material is available on the market, the high price preventing widespread use. 

As an environmentally friendly, but also very expensive, halogen-free material that, following the current trend in the development of electronic products, also meets even higher technical requirements, the only alternative is ceramics. The concepts presented here based on the organic material polysiloxane can be understood as an ecologically advantageous, technological link between FR4 and ceramics.

Polysiloxane as the Base Material

Polysiloxane is used as an ecologically and economically optimized alternative to thermosetting circuit board material, which can be used in the form of foils or plates as a non-hazardous carrier material for electronic assemblies.

 Polysiloxane belongs to the group of silicones with the filler aluminum oxide. This thermally conductive and temperature-stable material is combined in a sandwich construction with a metallic carrier material, whereby inexpensive, miniaturized assemblies, especially in the power range, can be produced. With a suitable construction principle, such as stabilizing the flexible printed circuit boards with expanded polypropylene (EPAC principle), mechanically extremely robust structures result. The metal also serves as a cooling plate.

What is the Role of Passive Components in Halogen-free PCB?

In combination with printing technology, additional multi-layers and components such as capacitors, coils and resistors can be implemented cost-effectively. The basic concept can be shown in a study on ecologically optimized television electronics. The entire television chassis was applied to pollutant-free, thermally conductive, automatically processable (roll to roll) and problem-free recyclable siloxane film.

The passive components were integrated by means of polymer paste printing, saving resources and costs. In the prototype realized here, 120 components were printed in this way. For this, however, a paste or adhesive system first had to be specified. 

Production Technical Advantages

An advantage of using flexible materials, in contrast to other concepts such as the use of injection-molded circuit carriers, is that they do not entail an exit from known manufacturing structures. This is reflected in the costs, especially for high-volume products, and thus simplifies switching or use. Among other things, multi-layer circuits could also be produced inexpensively with the help of conductive paste printing. The overall benefits can be summarized as follows:

  • Roll-to-roll production is possible
  • High level of automation in production
  • Favorable thermal properties
  • Integration of components in the carrier
  • Inexpensive materials and manufacturing technology
  • Good EMC properties
  • Reduced variety of materials
  • Saving of component assembly
  • Material savings (volume and weight)
  • Low-polluting materials

Further Research on Halogen-free, Flame-retardant Circuit Boards Based on Siloxane for Future Electronic Products

Although products have already been realized with the current state of development of this technology, additional research work is required for cost-optimized large-scale production. Further investments are made with the help of public funding and in cooperation with well-known companies for various investigations.

Examples include laser processing and microstructuring, local stiffening and the recently approved joint project “Halogen-free, flame-retardant circuit boards based on siloxane for future electronic products”, which deals with the development and manufacture of rigid printed circuit boards from the same material as the existing foils.

Halogen-free Material not only for Large Projects

In construction projects such as public buildings, airports, hospitals, kindergartens, exhibition halls, stadiums, town halls, to name just a few examples, where extensive pcb equipment are laid on cable racks in ceiling cavities or in cable ducts, halogen-free materials are now required.

The use of halogen-free pcb is usually stipulated in the specifications in the tender. The release of toxic gases would also have fatal consequences on ships, airplanes and trains, which is why halogen-free materials are mandatory here.

In fact, wherever people are, materials should contain the least possible risk in the event of a fire. These are offices, medical practices, retail stores and, last but not least, private apartments. The existing electrical installations do not represent the greatest potential risk in the event of a fire, because they are usually concealed.

Halogen PCB vs Halogen Free PCB Price Factor

The price is higher than ordinary halogen-containing PCB circuit boards.The cost difference is only considered from an economic point of view.

 However,manufacturers of SMT patches are still facing a more critical challenge:PCB drilling is greatly affected by the physical properties of the material,while the hardness of halogen-free materials It is usually higher.

Similarly,it is estimated that the life of the drill bit will therefore be reduced by about 25%.This is by no means insignificant, because for this reason, it is possible that halogen-free PCBs will cost higher manufacturing costs.When selling to an assembly plant,this cost will be reflected in the selling price of the product.

Most Common Compounds Used in PCB

This section lists some of the chemical compounds commonly used in PCB manufacturing and how they affect human life.

Copper chloride:This chemical is used as an etching solution in PCBs.When a person rubs his eyes after touching it,copper chloride can cause severe eye irritation.

Zinc chloride:Zinc chloride is used as a flux in printed circuit boards.This chemical can cause eye problems,breathing problems,and may affect the heart and lungs.If a person inhales zinc chloride,it may cause pulmonary edema and severe stomach problems.

Cobalt sulfamate: Cobalt sulfamate is used for electrolytic plating of PCBs.This plating agent can cause skin and eye irritation.

Bromine: Bromine is used as a flame retardant for PCBs.High levels of bromine can cause skin irritation,burns,dizziness and headaches.

Chlorine: Various chlorine-based materials are used in PCB manufacturing.Regular exposure to this chemical can cause tearing, nausea, headache, skin irritation, burns and dizziness.Furthermore,the handling of bromine, chlorine or halogen PCBs becomes difficult because they generate toxic fumes when burned.

 Lead: Lead is used as a flux in PCBs. Tin-lead is used to prevent oxidation in copper circuits.Lead produces toxic fumes during the soldering process and can cause breathing problems and other serious health problems.

Why Halogen Free PCB Has Become a Necessity

In the printed circuit board (PCB) industry, the wind of Halogen free PCB is blowing hard.Halogen compounds such as bromine have been widely used in PCB raw and subsidiary materials.

But they are losing their place due to strengthening regulations on the use of harmful substances in electronic products in advanced countries such as Europe and the United States.

The PCB industry is also moving in step with the declaration of ‘free halogen’ in order to prevent factors that could be regulated by electronics and mobile phone manufacturers. Starting with mobile phones with a simple manufacturing process, ‘halogen-free’ is now recognized as a necessity rather than an option in other products.

Every year,the electronics industry demands that increasingly small and dense printed circuit boards (PCBs) in electronic and micro-electronic components (miniaturization) operate in more aggressive and harsh environments.

Most Common Applications of Halogen Free PCB

In recent years,the shift to halogen-free materials (materials that do not contain halogen) has been promoted due to increasing awareness of environmental issues. The halogen of the material can be measured by resistance heating type quartz tube combustion- ion chromatography method.

As an example,you can take out the electronic board mounted on a mobile phone,a personal computer (new model),or a personal computer (old model) and check if it has a Halogen free PCB.

  • Application examples
  • CFRP contained halogen analysis
  • Resin/ceramics contained halogen analysis
  • Solder material contained halogen analysis
  • RPF contained halogen analysis

Related standards

◆ Japan Electronic Circuits Association (JPCA): JPCA-ES0206, JPCA-HCL21

◆ International Electrotechnical Commission (IEC): IEC61249-2-21

◆ American Electronic Circuits Association (IPC): IPC4101B

In recent years,customers’ requests for eco-friendly products have been increasing.In Europe,the RoHS directive has been enforced in Europe,and there is an urgent need for PCB manufacturers to respond to the environment.

Benefits of Using Halogen-free PCB

Now that you know the facts, why use halogen-free PCB?

The main advantage is that they are less toxic alternatives to halogen-filled alternatives. Prioritize the safety of you, your technicians and those who will handle the circuit board, enough to consider using a circuit board.

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, lower halogen content ensures 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 should be halogen-free.

However, reduced toxicity is not the only advantage: they also have performance advantages. These PCBs can usually 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.

Final Words

Halogen-free PCB insulation materials may be low-cost and effective for disposable electronic products. Finally, 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.

Halogen Free PCB Conclusion

With the planned launch of the 5th generation mobile communication system “5G” in the future,it is expected that data communication will have even higher capacity and higher speed.

Under such circumstances,the multi-layer circuit board materials that play a central role in servers and routers that support the backbone systems of communication networks are required to have Halogen free PCB materials.

It is from the perspective of the environment in addition to large capacity and high-speed transmission. Professional Halogen free PCB manufacturers have commercialized a substrate material for communication infrastructure equipment that is halogen-free.

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