Formance K has been developed to deposit pure, solderable silver layer on copper circuitry in compliance with IPC specification no. IPC-4553A. The deposit satisfies Class 3 final finish durability and is an excellent choice for demanding Pb-free assembly. Formance K is an easy to use product with simple analytical controls and straightforward replenishment that leads to lower running cost. Notably, the chemistry is EDTA- and alkylphenol ethoxylate-free and thus biodegradable.
Formance K is used in a standard immersion line, vertical or horizontal, incorporating the chemical steps of Cleaner, Microetch, Predip and Silver Bath with counterflow rinses in between. It is recommended to use an acidic cleaner appropriate for a final finish line (such as FinClean from RBP). The use of persulfate-based microetch is strongly recommended as it creates a better surface topography for immersion silver plating. An example of such microetch is Circutek ME-515 from RBP. Formance K Predip and Silver Bath are prepared from the components described below.
An alkaline cleaner for use in the LAYERBOND 2000 adhesion promoter process. PREPBOND provides complete surface preparation for this process, eliminating the need for a microetch. It completely removes residues from Resist Stripper, and is extremely effective for removing handling soils and fingerprints. For spray, flood and soak applications.
HASL Precleaner SLTM is a powerful, non-foaming, free rinsing, alkaline cleaner specifically designed to clean copper prior to HASL or alternative finishes. It will remove solder mask developer scum, oven baked oxidation and residues, fingerprints, and oils. HASL Precleaner SLTM will not etch copper nor will it damage the. HASL Precleaner SLTM can be used in conjunction with a light microetch or acid cleaner. If an acid cleaner is used, MicroCleanTM ZE is preferred. If a microetch is used, much lower levels of metal removal are fully acceptable, thus minimizing costs and reject rate. Because of the potent cleaning agents that destroy organo-metallic compounds (such as insoluble copper/soldermask compounds) present on the copper surfaces, use of HASL Precleaner SLTM will reduce the requirement for a second pass through the HASL.
A liquid persulfate-based copper microetch that is pre-mixed with sulfuric acid. ME 515L removes copper uniformly, providing good topography for subsequent processing. It can be used wherever a microetch is needed; prior to plating, resist lamination, solder mask over bare copper application, or solder leveling. ME 515L can be used in either soak or spray applications.