The PCB surface finish is one of the final stages of the PCB manufacturing process. Choosing the right finish for a PCB is critical for the assembly of the components on the board and can directly impact the PCBA process, quality, reliability and longevity.
The surface finish covers the exposed copper on the board’s surface, in order to prevent oxidation. Moreover, the surface finish acts as a solderable surface enabling the assembling (soldering) of the components to the board. For fine-pitch components the need for a thin, co-planar coating becomes even more essential.
The chosen surface finish also affects the durability, shelf life and cost of the board.
Read our guide to the different types of surface finishes by clicking this link.
The PCB surface finish chart below allows for easy comparison of the critical parameters, ensuring selection of the most appropriate finish depending on specific needs and requirements.
- Properties
-
OSP
OSP
Organic Surface Protection (ENTEK)
-
HAL
HAL
Hot Air Levelling, Pb Free (Optional non PB Free HAL), not preferred for fine pitch due to thickness variation
-
Immersion Ni/Au
Immersion Ni/Au
Immersion Nickel Gold, ENIG
- Immersion Ag
- Immersion Sn
-
Immersion Ni/Pd/Au
Immersion Ni Pd/Au
Immersion Nickel Palladium Gold, ENEPIG
- Electrolytic Au Soft
- Electrolytic Au Hard
Production
- Process Effort
- Low
- Medium
- Medium
- Medium
- Medium
- Medium
- High
- High
- Planarity
- Yes
- No
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- Thickness indication
- 0,2μm
- 3-25μm
- Ni 3–5μm Au 0,04μm - 0.1μm
- Ag 0,125 – 0,65μm
- 1μm
- Ni 3–5μm Pd 0,2-0,5μm Au 0,05μm
- Class 1 and 2 Ni min 2um Au min 0.8um Class 3 Ni min 2.5um Au min 1.25um 0.8um
- Class 1 and 2 Ni min 3um Au min 0.3um Class 3 Ni min 3um Au min 0.8um
Application
- Rigid
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- Flex
- Yes
- Not Recommended
-
Restricted
RESTRICTED
Stiffener to be used to avoid excessive stress on the surface finish due to bending
- Yes
- Yes
-
Restricted
RESTRICTED
Stiffener to be used to avoid excessive stress on the surface finish due to bending
-
Restricted
RESTRICTED
Stiffener to be used to avoid excessive stress on the surface finish due to bending
-
Restricted
RESTRICTED
Stiffener to be used to avoid excessive stress on the surface finish due to bending
- Rigid Flex
- Not preferred
- Not Recommended
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- Wire Bonding Al
- No
- No
- Yes
- No
- No
- Yes
- Yes
- No
- Wire Bonding Au
- No
- No
- No
- No
- No
- Yes
- Yes
- No
- Press fit
- Yes
- Yes
-
Restricted
RESTRICTED
Only in combination with suitable connector, check connector documentation
- Yes
- Yes
-
Restricted
RESTRICTED
Only in combination with suitable connector, check connector documentation
-
Restricted
RESTRICTED
Only in combination with suitable connector, check connector documentation
-
Restricted
RESTRICTED
Only in combination with suitable connector, check connector documentation
- Fine pitch
- Yes
- Not preferred
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- HDI - BGA
- Yes
- Not preferred
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- Multiple Solderability
- Restricted
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- Yes
- Cost
- Low
- Low
- Moderate
- Low
- Low
- High
- High
- High
-
Shelf life
Shelf life
Storage under the following conditions assumed: Original sealed packaging; Temperature 20-24°C, Relative Humidity 30-40%
- 3 months
- 12 months
- 12 months
- 6 months
- 6 months
- 12 months
- 12 months
- 12 months
- Refresh of surface
- Yes
- Yes
- No
- No
- Yes
- No
- No
- No
- Handling assembly
- Gloves preferred
- Gloves preferred
