Good Morning, We usually require soldermask over bare copper and tented vias (less than .020"). This typically means that the soldermask is dry film. If a tented via is not required and liquid soldermask is used, it appears that the soldermask is suspect to flake off near the via knee, leaving a small amount of exposed copper. Is liquid solder mask over bare copper compliant with vias when the plating is eletroless nickel - immersion gold? Does the plating type matter? Is the suspect of exposed copper a non-issue? Thank you in advance of any comments. Kevin Thorson Lockhead Martin Eagan, Mn