TechNet:

We are getting a condition known as "artwork marking" when exposing LPI
soldermask. This condition exhibits itself as shiny areas where the artwork
comes into contact with any high spots on the mask.
Although it appears to be totally cosmetic, we have a few customers who
refuse to purchase boards with this condition.

We primarily use Electra EMP110 soldermask with a Teledyne DSA 2000 spray
coater. The panels are then tack dried in a tunnel oven for 45 minutes at
180F.

When imaging the panels, the top side (against the mylar) seems fine but
the bottom (against the glass) is marked. The degree of marking varies
depending on the surface of the board.

Has anyone else seen this problem, or had the need to eliminate it?
Also, what method do you use to ensure sufficient tack dry prior image, if
any?

Any responses would be appreciated

Thank You
John Lennox
Process Engineer
EMC

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