Electroless nickel immersion gold (ENIG) / Chem. Ni/Au 

Tech info:  

• Electroless Nickel Immersion Gold  
• Typ. Au-coat 0.07 – 0.12 µm  
• Typ. Ni- coat 4 - 7 µm  
• Process temperature ∼ 90 °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:

• Fine pitch structures and micro vias  
• Al-wire bonding  
• Keypads  
• FLATcomp circuit boards  
• Rigid-flexible circuit boards