Hello all, Just a quick note for reference. The MicroBGA® CSP was designed to obviate concern over the solder joint as a compliant element. In the µBGA® CSP, the compliant layer in the package absorbs most of the stain of CTE mismatch between silicon and FR-4 substate. As a result, the solder ball metallurgy is not a great concern beyond allowing a good joint to be easily and reliably formed in the assembly process and have sufficent strength to hold fast the component in use. Kind regards, J. Fjelstad At 12:41 AM 3/30/99 -0800, you wrote: > Hi, Guenter, Werner... > An opinion within the group of "leading lights" of UK technology, > claim that "the lead free legislation is good timing" as Sn/Pb alloys > do not have the reliability of other alloys, particularly with regard > to modern components such as CSPs and Micro BGA. > > I have always understood that Pb makes Sn/Pb alloys very plastic and > thus extreemly reliable under the stresses of thermal cycling. > > If there are more reliable alloys, what might they be? > Which alloys present us with a higher degree of plasticity? > > Regards > Edward Brunker > PSION Computers > >################################################################ >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 ################################################################