SMT Solder Pads Below Surface of Solder Mask?

[EEMan1972]

I'm wondering if it is possible to have a SMT solder pad sit below the surface of the solder mask. In other words, if you were to take your finger and run it along the solder pad you would catch the edge of the solder mask because it is sitting higher than the pad. Has anyone tried this or do they know if it's possible to manufacture? Intuitively you'd that with a low profile solder pad and a thick solder mask this would be possible but I've just never tried to have it made. Any insights?

 

[zappedagain]

Yes, it is standard practice, especially for BGAs. It is called' Solder Mask Defined Pads'.

http://www.indium.com/blog/optimiza...pper-defined-non-solder-mask-defined-pads.php

Z

 

[mcgyvr]

yes.. most PCB layout programs have settings somewhere for "solder mask swell/shrink" and "paste mask swell/shrink"