The research further confirmed that procurement requirements for wrap plating thickness from IPC-6012 Class 3 to Class 2 would pose little risk to reliability. Experimental results corroborated by modeling indicate that the stress maxima are inside to the barrels somewhat than at the wrap location. There are a number of possible elements with respect to the chemistry and operational parameters of the micro-etch. An internal research checked out micro-etch basic compositions (sodium persulfate, hydrogen peroxide-sulfuric acid and potassium persulfate). The outcomes of numerous controlled checks with the same design of check vehicle showed that sodium persulfate yielded the greatest quantity of copper elimination.
shows a 5000X SEM micrograph of a non-corroded nickel surface after Au stripping. Capable of depositing greater thickness of gold (up to 7µin), if desired. To spotlight and mitigate nickel corrosion defects, the IPC Plating Processes Subcommittee revised the 2002 normal IPC-4552, Performance Specification for Electroless Nickel/Immersion Gold Plating for Printed Boards. Work on revision B occurred in 2019, and that document awaits a ultimate IPC member vote. Upon launch of IPC-4552B, corrosion inspection will turn into obligatory.
ENEPIG has been round for about 10 years and it has been touted as being a suitable alternative for ENIG. The proof points to it having comparable corrosion publicity and black pad problems. We have seen evidence of each forms of failures, so we don’t recommend this end. The expectation is that Ni corrosion would not happen in ENEPIG, as the Au ions don't have any direct access to the Ni.
If the Pd layer is thinner (1 to fourµin/0.025 to 0.1µm), it isn't totally impervious, and the Au ions may have access to the underlying Ni, providing a better path to IG deposition. Sample 2 RAI gold at 1000X, exhibiting degree “0” corrosion/product ratio. Sample 1 RAI gold at 1000X, showing level “zero” corrosion/product score. Based on the classification, the spikes are a degree 1 or degree 2 corrosion, with a product rating of “level 1,” per the proposed IPC-4552B. Although this is not cause for rejection, it's a process indicator that implies greater levels of corrosion are potential.
The stabilized hydrogen peroxide gave minimal copper removal in accordance with the specified total etch price . This, unfortunately, is an all-too-widespread problem related to any plating course of .
A midrange price ending that's in style for North America and Europe because of RoHS and WEEE regulation. A good alternative to ENIG if you want good properties at a lower value. OSP prevents the copper from oxidation by making use of a really skinny water-based mostly natural compound. It is very environmentally friendly compare to other more toxic compounds used.