Hi Technet,

IPC-6012 mentions "when not specified on the master drawing the minimum conductor width shall be 80% of the the conductor pattern supplied in the procurement documentation".
This is fine for the tracks, but it may cause problems with the solderpads. Quite often I see that the 12 mil designed fine-pitch pads have a width of only 9.6 mil on the actual products, leaving a marginal process window for assembly.
I can live with 11 mil instead of 12 mil, but 9.6 mil is too small for my taste. The questions:
1)   Is there an additional specification for the etching tolerance of the solderpads ?
2)   If we put additional requirements on the master drawing, what would be an acceptable value ?

As always I'm very interested to hear your comments,

Daan Terstegge
SMT Centre
Thales Communications
Unclassified mail
Personal Website: http://www.smtinfo.net

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