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34 SMT Magazine • February 2014 the pad. Tweezer alignment is described in the JEDEC standard (Figure 4), however it is very operator dependant and may not be performed properly. Any amount of torque or excessive deformation of the solder joint may result in changes in peak load to failure or failure mode. Therefore it is critical to test many solder joints of a given sample to accurately evaluate the re- peatability of the data. It has been shown in this work that similar failure modes can be gener- ated with a narrow distribution of peak loads to failure if proper tweezers are selected and care is taken in solder joint alignment. HBP testing is an alternate technique for mechanical testing of solder joints in electronic devices. Historically the hot pin method is used in Japanese testing standards and has been ad- opted by the military as acceptance criterion for laminate materials where a single unsupported land is repeatedly thermally stressed (Mil-P- 5884D). Other standards also required thermal stressing of laminates and pads (IPC-6012, IPC- 6013, and IPC-9708). This test method is signifi- cantly different than CBP testing in that heat is applied to the solder joint through a high- purity Cu pin or a soldering iron Figure 5. Once the pin reaches a temperature above the melt- ing point of the solder it is brought in contact with the solder at a pre-selected depth. It is arguable that this process cannot be compared to CBP due to its effect on the sol- der joint intermetallic structures. The tempera- ture gradient of this process and the addition of Cu from the pin to the solder system must be FEATUrE TeSTING INTerMeTaLLIC FraGILITy ON eNIG uPON aDDITION OF LIMITLeSS Cu continues Figure 4: Tweezer alignment 6 . Figure 5.