At 02:43 PM 1/19/2004 -0700, you wrote:
>When you're specifying solder mask, how much larger does the stop mask have
>to be than the pad?  If I have an 80 mil pad, can I use an 80 mil stop mask,
>or does it have to be larger?

Larger, depending on the process. Talk to your PCB house. Rough ballpark:-

LPI maybe 1-2 mils bigger all around
Dry film 3-5 mils bigger all around
Screened maybe 5-10 mils bigger all around

Double the above figures for the diameter.

Best regard,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

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