Tests in the US concluded that lead-free solders were no better, or worse, than traditional lead based solder, just different, and overall provide no benefit to the environment, especially if lead is adequately controlled. Not enough to allow for an exemption but this would have been thought provoking when the restriction of lead in RoHS was first considered. Since use of lead-free solders became widespread there have been few problems reported although many manufacturers expressed concerns over long term reliability. However, the Microsoft Xbox has clearly suffered a large number of failures which, according to published articles, may well be caused by lead-free soldering to either a BGA (ball grid array) package or a CSP (chip scale package).
It is reported that a large number of failures appear to be down to de-bonding of solder joints to a GPU (graphics processing unit) which is a BGA packaged device. According to a German computer magazine the reason for the problem was that the wrong type of lead-free solder was used, a type that when exposed to the high temperatures that most video game consoles generate, became brittle and developed hairline cracks that were almost irreparable. Three of the largest resellers in the world claimed a failure rate of over 30% on the Xbox and, at that time, 2500 defective units per day were returned for repair in the UK alone, and many of these failed again after a few weeks. It is also claimed that Microsoft spent up to $100 on each Xbox 360 to fix them. The consoles design uses heatsinks, fans and vented openings to dissipate the heat but the potential still exists for a significant build up of heat. Problems associated with overheating include reduced system performance and instability that may result in crashing or hardware failures. The change to lead-free solder makes good soldering to BGA’s more difficult but this in itself is unlikely to be the sole cause of failures as these can also occur with tin / lead soldered BGA’s. There are now reports that larger heatsinks are used to help prevent the problem of overheating. Directive Decoder