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Halogen Free PCB

Halogen free PCB

Halogen free PCB is a printed circuit board non-contain any halogen elements, During PCB manufacturing, the concerned halogen elements like Chlorine and Bromine do have some benefits however these do not outweigh their negative impact that can be caused in our day to day life. As a responsible PCB manufacturer, We are committed to producing circuit boards under environmentally friendly conditions

We are using following raw material to manufacture halogen free PCBs :

Halogen free PCB material, base on JPCA-ES-01-2003 standard: a copper-clad which the content of C1, Br less than 0.09%wt, it is called for halogen free PCB. (at the same time, the total value of Cr+Br ≤0.15%[1500PPM). Halogen free material: TU883, Isola DE156, Green speed series, S1165/S1165M, S0165, and so on. The EU has a strict import requirements from July 2006 ,the requirements details is the PCB products should be without halogen, mercury, hexavalent chromium, polybrominated biphenyls, polybrominated biphenyls ether .

More PCB material reading guilde:

Why halogen free?

The halogen harms the PCB electric strap, which includes bromine, chlorine compounds. Plastic products include flame retardants and PVC, and it is easy to produce hazardous substances, such as dioxin and acid gas (HCl) when burning. The hazardous substances harm the environment and human health. They have been listed as persistent organic pollutants by the  International Environment organization.

Halogen is widely used in PCB, solder mask, molded compound, and connector. For example, the Flame retardant of PCB has  halogen material; Among them, the toxicity of PBB and PBDE is the most concerning. The halogen PCB and electrical products will produce lots of byproducts like dioxin, furan, and acid or corrosive gases. They are harmful to the environment and human health. Most electric power and communication cables has halogen, and burning the cable will emit toxic chemicals.

The acid gases from the cable will damage the nose, mouth, and throat. It was difficult to escape from fire because the smoke is disorienting. So the ROSH from EU forbids PBB and PBDE such halogen material use in PCB board production. As a result, halogen material is forbidden because the components will create dioxins when burned. The requirements beyond original ROSH  which forbids the use of PBB and PBDE only.

Halogen free PCB will be a new environmental protection after guidelines from 1st July 2006. RoHS directive restricted the use of six hazardous substances such as lead Pb, cadmium Cd, mercury Hg, hexavalent chromium Cr6, four kinds of heavy metals, polybrominated diphenyl ether PBDE, polybrominated biphenyl PBB, and two kinds of flame retardants.

Among them, Pb has direct damage to the nervous system. Cadmium can damage the bones, kidneys, and respiratory system. Mercury can damage the central nervous and kidney systems. Hexavalent chromium can cause inherited genetic defects. From ROSH to Halogen free, to Norway’s POHS, which forbids the use of 18 kinds of hazardous substances, the stringent environmental requirements for materials not only can reduce the environmental impact of electronic products but also protect our health.

The reason of halogen free:

  • Impact on the environment and healt
  • Brominated flame retardants (like PBB and PBDE) have toxins
  • The structure of brominated flame retardants is similar to lots of toxins in PCB
  • Stimulates all BFRs precautionary psychology
  • Toxin is the byproduct when burning a product
  •  Dioxin is produced if halogen burning is incomplete
  • electrical scrap burning at normal temperature condition all over the word
  • Environmental groups strongly oppose brominated flame retardants
  • OEMs are seeking halogen free solutions and extending this requirement throughout the supply chain due to pressures from environmental groups
  • Major OEMs announce the elimination of bromid

Apple: Eliminate PVC and brominated flame Retardants at the end of 2008
DELL: Eliminate brominated flame Retardants in 2009
HP:Eliminate PVC and brominated flame retardants in 2009 

Burning chlorinated carbohydrates will produce small amounts of dioxins and furans.
According to fire data, dioxins and furans from fire accident have small effects on human health

Regulations limiting halogens

Halogen free fr4 pcb
  1. EU 2002/95/EC (ROSH instruction)

 Restricted substance: Brominated flame retardants

  • 《Montreal Protocol》

 Restricted substance: Five chlorofluorocarbons and three kinds of halon

  • 《Stockholm Declaration》

 Restricted substance: Organochlorine pesticides: HCB,PCBs, PCDDs,PCDFs

  • IEC 61249-2-21

Maximum limit: Total halogen of chlorine and bromine

  •  How to test halogen?

Halogen free purpose: The content of bromine and chlorine less than 900ppm, and bromine and chlorine total content less than 1500ppm

Halogen free PCB principle

Most of the halogen free materials are phosphorus series and phosphorus – nitrogen series. Phosphorus resin in the combustion,will produce polyphosphoric acid, it has high water absorbability, the polymer resin surface come into being a carbonization film, the film insulate resin combustion and air,, so that the fire extinguish then to achieve flame retardant . Polymer resin containing phosphorus and nitrogen compounds, combustion produces incombustible gas to help the resin system flame retardant

Halogen free PCB material characteristics

Advantages:

  • Excellent heat resistance
  • Low z-axis
  • Better for PCB impedanceProduction
  • High TD

Disadvantages

  • Low peel strength
  • Poor alkali resistance
  • High bibulous rate
  • Bad CAF resistance
  1. The water imbibition of PCB material

 the N and P of halogen free PCB is less at the oxygen resins nitrogen and phosphorus system   The  hydrogen atoms in water is lower than halogen materials, so the water absorbability is lower than conventional halogen flame retardant materials. For raw materials, low  water absorbability has a certain influence on improving the materials reliability and stability

2. Insulation of materials

 The polarity of resin molecularis reduce because use P or N instead of halogen atomic, it is increase insulativity  and abrasion resistance

3.hermal stability of materials

The content of nitrogen and phosphorus in halogen free PCB material is higher than common halogen materials, so monomer molecular weight and Tg value increased.

The molecular mobility will be lower than conventional epoxy resins under heat conditions, so the thermal expansion of halogen free PCB material will be more smaller. Compared with the halogen PCB, the halogen free PCB has more advantages, and the halogen free PCB is the general trend to replace the halogen PCB. Lamination space, different brand material will not be the same. 

For example, Shengyi raw material  multilayer PCB. in order to ensure the full flow of resin and  force is acceptable, it is request low heating rate of sheet material (1.0-1.5℃ / minute) and multi-stage pressure, and the  others in the high-temperature stage require a longer time; 180℃ to maintain more than 50 minutes.

About halogen free PCB

Halogen free PCB advantage and application

1. Advantage: Halogen free PCB without halogen that will minimize the environmental impact and conform to future green environmental protection requirements.

2. Disadvantage: halogen  PCB is very crisp and easy to has white spots, especially raise more stringent production technology standards for solder mask and shape production.

Currently, most raw material suppliers develop halogen free copper-clad and PP like Polyclad PCL-FR-226/240, Isola DEl04TS, Shengyi S1155 / S0455, Nanya, Hongren GA-HF and Panasonic electrician GX series, and so on. We started bulk production using Polyclad’s PCL-FR-226/240 panels in 2002. This year, we have developed a S1155 substrate and multilayer panels. We are also trying to use Nanya halogen free PCB. Presently, the use of halogen free plates has accounted for 20% of our total plate consumption.

Halogen free PCB are widely used in substations, power stations, distribution rooms, laboratories, and outdoor electrical operations.

The attentions during Halogen free PCB production

Halogen free PCB raw material

Technical difficulties and special process:

  1. How to control the raw material is inflated and shrinked?
  2. How to control the laminate parameters and compensation of inner film?
  3. How to control the drill precision?
  4. How to control the clear of PCB?
  5. How to control the raw material is inflated and shrinked?
  6. How to control the laminate parameters and compensation of inner film?
  7. How to control the drill precision?
  8. How to control the clear of PCB?

How to control the wash board frequency for green solder mask?

1. Cut material: Use 150℃ to bake the raw material for 6 hours after cutting the material

2. Press PCBA. Pay special attention to the press PCB data

          B. Cut horizontal and straight material. The film elongation coefficient is:Horizontal and straight lengthwise  is 3.5%,lengthen the width is 0.5%, straight materiallengthwise is 0.5%,lengthen the width is 3.5%

             C. Press the boards at 150℃ for 4 hours

3. Drill hole

Drill hole is an important process and can affect PCB quality during production. Halogen free copper-clad increases molecular weight, the rigidity of molecular bonds, and material rigidity because of P,and N series application. At the same time, halogen free PCB TG value is  higher than normal copper clad, so the drill hole quality will not be perfect if FR4 drill the hole is used in FR4 . Drill hole should be adjusted with halogen free PCB under normal drill condition

A. The material utilization is higher than normal FR4 material

B. The turn speed decrease about  10%

C. Drop speed decrease about  15%

D. Knife Operating speed decrease about 10%

E.drill work  less than 2 times

F. The max number of drill tools less than 500pcs

G. Bake the PCB at 150℃ for 4 hours after drill hole (only for 4 layer PCB, 2 layer PCB don’t have such request)

4. Electroless Plating Copper

A.Normal expansion temperature

B. Expansion time is twice (Normally it is about 15 minutes)

C. Normal cleaning related

5. Etch and solder

Green solder mask PCB forbid to wash, The first sample should be attention.

The alkali-resisting halogen free PCB material is worse than normal FR-4; we should pay special attention to etching and solder mask production

  1. Bake  2 hours with 120℃ before packaging
  2. More tips to control halogen free PCB production

Purchase:The quality of halogen free PCB material

IQC:Check the halogen free PCB material quality

Warehouse:Management of halogen free PCB material. Do not mix up with other materials

Cut material:Halogen free PCB material marked

Production:The halogen free PCB material’s application (mostly green solder mask, silkscreen, OSP, and immersion tin)

Engineer:MI/LOT document. Do not mix up the material during production

OQC:Halogen free PCB testing, verification, and reporting 

Test Lab:XRF test data analysis

Package: Remarked and logo request from customer

  • 8. Detection and analysis of halogen Free PCB

In order to provide evidence that the material is halogen free, the manufacturer must do a firm burning test and then check whether the materials have halogen elements or not by ion chromatography. The bromide activator materials decompose during combustion, and in these materials, the atoms of bromide combine covalently at room temperature to form bromide molecules.

Test Method


(1)EN 14582 feature of waste – Halogen and sulfur content – Oxygen combustion in closed systems and determination method 
method A (Calorimetric bomb method) 
method B (Schoniger flask combustion method) 
(2)IEC 61189-2 test method, apply for electrical material like HDI PCB, and electronic components
 TEST 2C12 test method apply for HD PCB only

(3)JPCA-ES-01-2003 
 Halogen free PCB material test method
 (4)IPC TM-650 (Number2.3.41)

Halogen free PCB has low water absorption and can meet environmental protection requirements and PCB quality requirements. As a result, the demand for halogen free PCB will increase.