Hi Herminia,
Just because people sell you some equipment that does give some data does not 
mean that the data are meaningful.

No, there are no IPC shear/pull test specification. And there are good 
reasons none exist.
First, there cannot be such thing as a true 'shear/pull test;' while you are 
of course stressing the solder joint, what you are doing to the solder joint 
in most cases is primarily peeling it—the proper reference would be a ' 
peeling' test. this is true whether you are concerned about leaded solder joints or 
leadless solder joints [e.g., solder balls]
Second, the solder joint strength, as determined by a such a peeling test, 
has no bearing on the reliability of the solder joint, provided the peeling test 
does not reveal inadequate wetting or poor metallization, e.g., 'Black Pad.’
Third, in a peeling test you always need to observe the whole peel-load 
history for the whole peeling process; e.g., for gullwing leads with a 1T or larger 
heel fillet, the largest load will be at the initial portion of peeling 
through the heel fillet, with lower loads subsequently depending on whether or not 
(or to what extent) side fillets are present.
Fourth, the fracture surfaces of the peeled solder joints give typically more 
information than do the peel-load histories, because the ONLY really 
important finding is whether or not adequate wetting has taken place, i.e. the 
separation is mostly in the solder vs. being interfacial; or whether or not the 
metallization is the 'weakest' link, i.e. the separation is between metallization 
layers. Good quality solder joints frequently cause failure between the 
soldering pad and the component/PCB resin matrix.
Fifth, for leaded solder joints, the reliability in actual use does to a 
large extent depend on the heel fillet and the 'bottom flat' wetting; if the foot 
length is <3W, than also on the presence of a toe fillet, because short feet 
'rock' during thermal cycling. Side fillets are less important, unless you have 
wetting problems. For leadless solder joints, the reliability is mainly 
determined by the solder joint height [gap vs. ball vs. column] everything else 
being equal. Having said all that, solder joints attached to nickel surfaces 
[ENIG, Alloy 42] will always show lower peeling--ball shear--strength than solder 
joints to copper if proper wetting has been achieved and no 'weak link' [e.g., 
'Black Pad, Kirkendall voids, champagne voids, inadequate solderability] 
exists in the metallization.

Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com

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