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solder mask on wrong layer

Question asked by volain on Jan 12, 2012
Latest reply on Mar 16, 2012 by jmatthews

Here's a strange one.  I created two fiducial decals, one for the top layer(FIDTOP) and one for the bottom (FIDBOT).  The top fiducial pad stack defines a pad (on 'mounted side') of 50 and a pad on the TOP side solder mask of 150.  The bottom fiducial also has a mounted-side pad of 50 and a BOTTOM side solder mask pad of 150.  BUT when I place the bottom fiducial, there's no pad on the bottom solder mask.  BUT, miraculously, there's a pad on the TOP side soldermask. In other words, regardless of which soldermask layer I place a pad on, it ends up on the top.   After wasting 2 hours of my life on this, I discovered the following:  If I place FIDTOP on the bottom layer, the pad explicitly defined for the TOP side soldermask appears on the BOTTOM side soldermak. It appears that when generating soldermak layers, PADS interprets "bottom" solder mask as "OPPOSITE" soldermask

 

Is that the way this is supposed to work? What's the point of explicity telling a pad what layer to go to, when the software is just going to stick it wherever it wants?

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