Here’s some of the things we often see missing or unclear at Sierra when customers send us fab notes:
- Controlled impedance requirements
- Board manufacturing specifications
- Which side is the primary side
- Material requirements
- Plating details
- Solder mask color and specifications
- Surface finish
- Gold finger requirements
- Critical mechanical and hole-position tolerances
- Via-in-pad or plugged via requirements
- Blind and buried via details
- Board, etching, and plating tolerances
And here’s one worth remembering: if something isn’t specified, don’t assume your fab house will automatically choose what you had in mind. For example, if you leave out the surface finish, we may use its standard/default finish.
