In PADS Layout I do see that solder masks are OK. When I generate the Gerbers, for some components all pins are connected together and no spacing between pins! What's the reason?
Your image is a negative; the pads are connected together by 'no mask'. Your Gerber aperture is too large to put paste between the pads, so PADS leaves it blank. Check with your PCB fabricator on your minimum width for solder mask, and then set your CAM photo plotter setup accordingly.
As usual your comments are very helpful.
You may be oversizing the pads too much in CAM. Edit the CAM setup file for the Soldermask layer and go to Options. See what it says in Under(Over)Size pads. Any value in this field will oversize the pads if it is a positive value or undersize them if it is negative. Check with the board house to see what their requirements are. It is common these days to use a zero oversize and let the board house adjust the size of the mask pads to suit their fab processes.
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