Printed circuit board surface finish application is one of the final steps in the manufacturing process and is designed to prevent oxidation of the remaining exposed copper. Selecting the appropriate surface finish is a critical material decision due to importance it plays in electronic assembly. The surface finish will influence the cost, manufacturability, quality, and reliability of the final product.

The chart below lists many of the surface finish options offered by Bay Area Circuits and provides some information regarding the characteristics and applications for each. If you’re unsure which surface finish is best for your project, contact us and we’ll be happy to assist you.

 

Characteristics

HASL HASL (LF) ENIG ENEPIG HARD GOLD SOFT GOLD SILVER OSP WHITE TIN
Deposit  Dipped Dipped Immersion Immersion Electrolytic Electrolytic Immersion Dipped  Immersion
 Process Control  Poor Poor Fair Fair Fair Fair Fair Poor/Fair  Fair
Process Cost Low Low Medium High High High Medium Low  Medium
SMT Dome Dome Flat Flat Flat Flat Flat Flat  Flat
Thin Board Finish No No Yes Yes Yes Yes Yes Yes  Yes
Thermal Cycle (times) >2 >3 >2 >2 >2 >2 >2 ~2  >2
Shelf Life Long
(1+ Yrs)
Long
(1+ Yrs)
Long
(1+ Yrs)
Long
(1+ Yrs)
Long
(1+ Yrs)
Long
(1+ Yrs)
Medium
(9-12 Mos)*
Medium
(9-12 Mos)*
Medium
(9-12 Mos)*
Handling Normal Normal Normal Normal Normal Normal Critical Critical  Critical
Exposed Copper No No No No Yes No No Yes  No
Contact Applications No No Yes Yes Yes Yes No No  No
Thickness 25 – 2000 μin 25 – 2000 μin 3 – 10 μin of Gold over 150 – 200 μin of Nickel 1 – 2 μin of Gold over 4 – 8 μin or 8 – 15 μin Palladium over 100 -150 μin Nickel 98% Pure, 23 Karat 30 – 50 μin over 100 – 150 μin of Nickel 99.99% Pure, 24 Karat 30 – 50 μin over 100 – 200 μin of Nickel 6 – 18 μin 8 – 24 μin 25 – 60 μin

Application

  HASL HASL (LF) ENIG ENEPIG HARD GOLD SOFT GOLD SILVER OSP WHITE TIN
RoHS Compliant No Yes  Yes  Yes  Yes  Yes  Yes  Yes  Yes 
Fine Pitch SMT No  No  Yes Yes Yes Yes Yes Yes Yes
BGA & μBGA No No Yes Yes Yes Yes Yes Yes Yes
Flip Chip No No Yes Yes Yes Yes Yes Yes Yes
Wire Bonding No No  Yes (Al) Yes  No  Yes (Au)  No  No  No 
Contact / Connector No No Yes  Yes  Yes  No  No  No  No 
High Reliability High  Low/Medium  High  High  Medium/High  High  Medium/High  Medium/High  High 
Solder Joint Integrity Excellent  Good  Good  Good  Poor  Poor  Excellent  Good  Good 

 

*Requires Unique Storage Techniques

μin = Microinches