Electroless nickel/immersion gold (ENIG)

Technical Info:

• Electroless Nickel Immersion Gold  
• Typ. Au-coat 0.05 – 0.1 µm
• Typ. Ni-coat 4 – 7 µm  
• Process temperature ~ 80 °C
• Max. shelf life 12 months

Advantages:

• Universally suitable surface finish  
• No Copper attack during soldering process, Nickel serves as diffusion barrier  
• Smooth surface  
• Soldering (with or without lead, mulitple soldering)  
• Storing between solder processes is possible  

Disadvantages:

• Relatively expensive  
• Certain limits for press-fit application  

Application fields:

• Flex-rigid boards
• Fine pitch structures and micro vias    
• Al-wire bonding