Leadfree soldering
	Since Juli 1st the ROHS regulations on leadfree solderings are applicable for most commercial products. Leadfree soldering means that the lead is taken out of todays PbSn alloys and that these mostly will be replaced by SAC. For details, please have a look at www.loodvrijsolderen.nl. The problems you can expect with leadfree soldering are - Tin whiskers: this are small "hairs" that can grow quite rapidly from the Sn. Risk of these are that they can cause shorts. It can be tested with 85/85 test. Prevention can be found in using correct type of solder and paste. - Voiding: these are very small holes in the solder connection. The risk is that the strength of the solder connection is lower than norman. As well the electric resistance might be higher. Voids can be detected by X-ray analysis. Prevention should be found in the soldering process (temperature curve). - Cracks: especially in BGA and CSP connections. The risk is that there is a dry solder joint or that the already cracked parts still make contact, which however is not guaranteed. So not reliable. Prevention can be done by using underfill. This is expensive, good design, where bending is prevented/reduced can improve too. - Brittleness/strength: the connections are less ductile then lead containing connections. The risk is that components will crack or will breakdown because the force or vibration is coupled in directly. Prevention can be done by good design, where the higher forces are taken into account. For example no critical components on stress lines. Tests Although PbSn was verified via simulation testing, today there are new techniques for testing, applied mainly because they are faster. The techniques are: 1. Simulation testing (old and proven) 2. Robustness testing (new, levels added to simulation tests)  3. HALT/HASS testing (new, new tests: 6 axis omnidirectional vibration combined with very fast temperature changes >100 K/min and on/off cycling. Today much testing is based on robustness testing, for example ROSE (Robustness Specification for Environmental testing) and MEOST Multiple Environment Overstress Testing. Thermal shock test, from -40 to +85 or +125'C is very often used. Minimal for 150 cycles, but because of test to fail filosophy it can be up to 1000 More to follow...