Immersion Silver
Pros
Cons
Good Wettability
Poor Shelf-Life: *Must be vacuumed packed for shipping *Must be vacuumed packed for storage *Must not handle Surface Areas
Good Coplanarity
Good Reflow Cycles
Good Process times
Low Cost
Fair Process Window
Good Process Control
Poor Adhesion
Good Electrical Testability
Difficult to Re-Work
Organic Solderability Preservative - OSP
Poor Shelf-Life: *Degrades with High Temperature *Must not handle Surface Areas
Good Surface Oxidation
Re-Workable
Very Low Cost
Reflow Cycles
Good Process Window
Flux Sensitivity
Poor Wettability
Very Poor Electrical Testability
Electroless Nickel Immersion Gold - ENIG
High Cost
Complex Process
Not Re-Workable
Ni/Sn brittle Solder Joints
Good Shelf-Life
Field Failure
Good Adhesion
Wire Bonding
Fair Process Control
Keypads
Hard Gold
White Tin
Long Process Time
Possible Tin Whiskers
Problems if Tin Thickness is Low
Lead-Free Hot Air Solder Leveling
Excellent Wettability
Process Control
Much Improved Coplanarity over Sn/Pb
Excellent Reflow Cycles
Excellent Surface Oxidation
Excellent Solder Joints
Excellent Shelf-Life