Polarity for Solder Mask Layers
Features
on a positive layer are considered copper. Features on a negative
layer are considered clearances. This is true for every layer except
the solder mask layer. Though solder mask is defined as positive,
the system considers it negative and its features are considered
clearances. Therefore, the solder mask layer should be set to positive
in the job matrix. If defined as negative, it may result in incorrect
results and long analysis.
