FEDEVEL
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mulfycrowh , 02-09-2021, 07:28 AM

Hi everyone,

The smallest solder mask sliver in my project is 0.12 mm and applies to the attached footprint.
0.12 mm is very small in front of the initial 0.254 mm.
Should I set the rule to 0.12 mm or something bigger with an exception for this chip?

Thanks.

WhoKnewKnows , 02-09-2021, 07:02 PM

I recommend finding out what the minimum SM sliver your fab shop can produce. Keep in mind that sometimes fab shop capabilities are so good that they can manufacture a SM sliver so narrow that it's not effective at preventing solder shorts. If your fab shop is also your contract assembly shop, ask them for a recommendation for minimum SM sliver. On a board that combines TH and SMT parts, if the CM is going to wave solder, you may want the solder side minimum sliver to be larger than the component side minimum sliver.

robertferanec , 02-15-2021, 12:29 AM

You can set the rule to 0.1mm so you will not be getting errors.

However, that doesn't mean your PCB manufacturer will able to manufacture it. For better PCB manufacturer, 0.1mm sliver is usually fine. However for cheap PCB manufacturer, they may not able to do it. Usually, if they can't manufacture it, they will just remove it - they may draw a big rectangle with no mask around your pins.

Example, JLCPCB can only do 0.2mm: https://jlcpcb.com/capabilities/Capabilities