OSP / Entek

OSP (Organic Solderability Preservative) or anti-tarnish preserves the copper surface from oxidation by applying a very thin protective layer of material over the exposed copper usually using a conveyorized process.

It uses a water-based organic compound that selectively bonds to copper and provides an organometallic layer that protects the copper prior to soldering. It’s also extremely green environmentally in comparison with the other common lead-free finishes, which suffer from either being more toxic or substantially higher energy consumption.

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Printed Circuit Board with OSP / Entek Surface Finish

ADVANTAGES
Flat, Coplanar pads
Reworkable (at PCB Fabricator)
Doesn’t Affect Finished
Hole Size
Short, Easy Process
Low Cost
Good Soldermask Integrity
DISADVANTAGES
X –Assembly Line Changes May be
Required; Not a “Drop-In” Situation
X  – Difficult to Inspect
X – Question Remains Over Reliability of
Exposed Copper After Assembly
X – Limited Thermal Cycles
X – Limited Shelf life
X – Panels Need to be Routed and
Electrically Tested Prior to Coating