IEC 60749-21:2011 establishes a standard procedure for determining the solderability of device package terminations that are intended to be joined to another surface using tin-lead (SnPb) or lead-free (Pb-free) solder for the attachment. This test method provides a procedure for 'dip and look' solderability testing of through hole, axial and surface mount devices (SMDs) as well as an optional procedure for a board mounting solderability test for SMDs for the purpose of allowing simulation of the soldering process to be used in the device application. The test method also provides optional conditions for ageing. This test is considered destructive unless otherwise detailed in the relevant specification. NOTE 1 This test method is in general accord with IEC 60068, but due to specific requirements of semiconductors, the following text is applied. NOTE 2 This test method does not assess the effect of thermal stresses which may occur during the soldering process. Reference should be made IEC 60749-15 or IEC 60749-20. This standard cancels and replaces the first edition published in 2004 and constitutes a technical revision. The significant change is the inclusion of Pb (lead)-free backward compatibility.