PCB Reverse Engineering

Reverse PCB lead - free process technical requirements

 1. EU WEEE and RoHs Directive
July 1, 2006 began to implement the EU WEEE and RoHs directive on China's electrical and electronic industry caused a great impact. EU WEEE and RoHs require production countries, production enterprises must be responsible for the recovery of electrical and electronic products, and electrical, Reverse PCB electronic products, hazardous substances proposed to prohibit, these harmful substances include: Pb (lead), Hg (mercury), Cd ( Cadmium), Cr (hexavalent chromium), PBB (polybrominated biphenyl), PBDE (polybrominated diphenyl ether), but does not contain tetrabromobisphenol and other substances. The quantification indicators of the prohibited substances are:
Pb (lead) <1000 * 10-6
Hg (mercury) <1000 * 10-6
Cd (cadmium) <1000 * 10-6
Cr + 6 (hexavalent chromium) <1000 * 10-6
PBB (polybrominated biphenyl) <1000 * 10-6
PBDE (PBDE) <1000 * 10-6
2. Lead-free on the basic requirements of the Reverse PCB 
2.1 Lead-free on the basic requirements of the PCB for the CCL and PCB body of the raw materials to resist solder, the surface of the solderable coating of the lead-free requirements
(1) conventional FR-4 CCL. Domestic main CCL manufacturer, the use of flame retardant series tetrabromobisphenol A, SGS detection, in full compliance with the requirements of the EU RoHS directive, excluding PBB and PBDE (not measured ) The other four heavy metals are not measured or the results meet the requirements.
(2) commonly used solder resist ink are also tested by SGS, six harmful substances are in line with the requirements of the EU RoHS directive.
(3) Reverse PCB  surface coating process. The original hot air leveling process Sn63 pb37 certainly can not meet the requirements, so our company developed the following lead-free surface coating:
① pure tin hot air leveling ②OSP (organic film oxidation treatment) ③ electroplating nickel ④ chemical nickel ⑤ chemical Shenyang silver ⑥ chemical production of tin in addition to the production of tin plating in the process of electroplating electroplating pure tin.
(4) to meet the appeal (1) (2) (3) requirements of the printed circuit board by SGS test fully meet the requirements of the EU RoHS.
It is also necessary to note that tetrabromobisphenol A (TBBA) is widely used in electronic and electrical products as a skeleton to improve the flame retardants as a complete reflection of the epoxy resin.TBBA has become the world's largest application of a bromine Flame retardants, the EU risk assessment confirmed that TBBA is safe for human health, and the conclusion is that tetrabromobisphenol A, which has been completely reacted as an epoxy skeleton, has no effect on the environment and does not precipitate, Function is the most effective flame retardant, but also from the health and environmental point of view is the most thorough research of flame retardants.In short, the world has no laws to limit the use of tetrabromobisphenol A.
(CI), bromine (Br) content of less than 0.09% (weight ratio), CI, Br total content of less than 0.15 %(weight ratio).
(6) China's development of halogen-free plate.
KB-6162 (Kingboard) Tg: 155 ° C
S1155 (raw) Tg: 135 ° C
S1165 (raw) Tg: 170 ° C
2.2 Several lead-free surface coating performance
The performance of several lead-free surface coatings is shown in Table 1.
Cover hot air leveling OSP plating nickel gold chemical nickel gold chemical Shen tin chemical Shen silver
No Good Good Good Good Good
Welding layer Cu-Sn Cu-Sn Ni-Sn Ni-Sn Cu-Sn Cu-Sn
Number of welds 6 2 6 6 2 6
Storage life is longer and shorter length shorter
Heavy duty ∨ ∨ NO NO ∨ ∨
Contact function NO NO ∨ ∨ NO ∨
Production costs high and high
Control thickness 6um-24um A 0.3um-0.5um
B 0.15um-0.25um Ni> = 3um
Au> = 0.05um Ni> = 3um
Au> = 0.05um 0.8um-1.2um 0.15um-0.3um
The standard requires weldable weldable weldable weldable weldable
Note: A is alkyl benzimidazole (ABI)
Note: B for the new OSP alkyl - phenyl imidazoles, can protect the appearance of gold finger color.


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