Hello all,

I ran into a problem recently where, while following our standard air gap
design rule of 5 mils, we placed a trace 5 mils from a pad and ended up with
bridging after assembly. It looks like with the combination of the
soldermask clearance from the pad (~3.5 mils) and the misregistration
between the soldermask and the pad, that the edge of the trace was left
exposed, picked up solder at HAL, and picked up some of the pad's solder
during assembly.

So, my question becomes, does anyone use different design rules for traces
next to pads than they would use for two parallel traces?

Thanks,
Matt

Matthew Sanders
PWB Procurement Engineer, Trimble Navigation Limited
[log in to unmask]
Phone: (408) 481-7817
Fax: (408) 481-8590

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################