Please find below a brief description of the thickness of surface finish for a printed circuit board:
 
  
   | 
    Surface Finish | 
   
     
    JetPCB Capabilities | 
  
  
   | 
    General Thickness | 
   
     
    Max. Thickness(please contact our sales representative) | 
   
    Notes | 
  
  
   
    HASL 
    HASL pb free | 
   
     
     0.7mil 
    
     (17.5μm) 
    | 
   
    1.2mil 
    (30μm) | 
   
      | 
  
  
   | 
    ENTEK/ OSP  | 
   
    0.4μm | 
   
      | 
   
      | 
  
  
   | 
    Immersion Tin (ImSn) | 
   
     
     30~40μ" 
    | 
   
      | 
   
      | 
  
  
   | 
    Immersion sliver (ImAg) | 
   
     
     6~8μ" 
    | 
   
      | 
   
      | 
  
  
   | 
    Immersion gold (soft gold) | 
   
    3~5μ" | 
   
    12μ" | 
   
    The general thickness for immersion gold is 100~120μ". If your specification is beyond this range, please contact our sales representative. For your information, our capabilities for such service can be reached to 350μ". | 
  
  
   | 
    Gold Plating | 
   
     
     3~5μ"  
    | 
   
    50μ" | 
   
      | 
  
  
   | 
    ENEPIG | 
   
    3~8μ" | 
   
      | 
   
      | 
  
 
The above mentioned are FYI, thank you.