Eric, I would have a hard time accepting that also. But one needs to know if you will flux or add solder paste. Since the ball dia has a tolerance on it, this affects ball volume and resultant total solder in the final ball solder joint. Also the attachment pad on PWB has a process tolerance at manufacturer which will very likely be not much better than +.000" and -.003" which equates to approx 20% range in area variation. This also contributes to the final height dimension. Collapsed height will very likely be more like +/- 0.004" or +/- 0.005" R. Kubes Honeywell DAS Albq > ---------- > From: Eric Christison[SMTP:[log in to unmask]] > Sent: Tuesday, October 13, 1998 8:55 AM > To: [log in to unmask] > Subject: [TN] Tolerance on Collapsed height of BGA Balls > > I am having difficulty in believing something a packaging engineer is > telling me. > > We have a design of sensor which is now BGA packaged. The balls are 0.030" > diameter and 0.023" high. > After reflow I am assured that the collapsed height will be 0.019" > +/-0.001"(given a correctly > dimensioned footprint) . I have no problem with the 0.019", it's the > +/-0.001" that stretches my > credibility threshold. > > Is there anyone out there that can confirm or deny this tolerance? > > Regards, > > > > > Eric Christison > > ################################################################ > 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 > ################################################################ > ################################################################ 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 ################################################################