All PCB surface finishes have strengths and weaknesses. Your PCB material must be chosen according to your project needs. This matrix is designed to allow you to make the best decision for your circuit board and PCB finish needs. View Sunstone's offerings here.

PCB Surface Finishes

Please review the information below for a side-by-side comparison of PCB surface finishes.

Final Finish Comparison Matrix Interpretation Immersion Silver (IAg) ENIG (Electroless Ni/Imm Au) Organic solderability coatings (OSP) Immersion Tin (ISn) HASL
(no-lead) 		HASL (Tin/lead)
Lead free compatible, RoHS compliant required yes yes yes yes yes no
Solder joint integrity (how good and reliable is the solder joint) self explanatory very good * good good good good best
Shelf life (with proper storage**) self explanatory 12 months** 12 months 12 months** 12 months** 12 months 12 months +
Assembly heat cycles (# of passes through reflow) > is better multiple multiple multiple multiple multiple multiple
Fab thermal shock (thermal shock during PCB fabrication) very low is best very low low * very low very low high high
Wettable (how easily does the solder flow onto the surface) self explanatory very good * good good good acceptable * best
Solder paste printability (co-planarity of the finish for fine pitch devices) self explanatory excellent excellent excellent excellent poor poor
Solder pot compatible (low possibility of solder pot contamination) desired yes monitor Au concentration yes yes yes no (if using no lead solder pot)
Low contact resistance (resistance of the finish) yes is good yes yes yes no no no
Aluminum wire bonding (can this finish be used with Al wire bonding) yes is good yes yes no no no no
Process cost to PCB fabricator self explanatory med high low med high low

Sources: (1) Cookson Electronics, (*) Sunstone testing data (**)

For more information on the immersion silver process used by Sunstone please go to: Microvoids.org