According to an extensive solder reliability study conducted by the Solder Products Value Council (SPVC), an IPC group, the tin/silver/copper (SAC) alloy family of lead-free solders is producing greater voids in the solder joint. Voids in solder joints are empty spaces within the joint that can be detected by X-ray imaging. Voids in SAC solders have been greater than 25 percent of the joint, a rejectable size for tin/lead solder joints.
The report notes, however, that the lead-free solders are reaching equivalency with the performance of tin/lead solders in spite of the larger voids. The report concludes, "there is no evidence that the type of solder joint voiding observed in SAC-alloy joints had any affect on solder joint reliability."