High lead solder (over 85 %) solder in the electronics industry: RoHS exemptions and alternatives

Abstract

The restriction of hazardous substances (RoHS) directive passed in 2006 prohibited the use of certain hazardous substances, including lead, in electrical and electronic equipment. However, high melting temperature type solders (i.e. lead-based alloys containing 85 % or more lead by weight) were exempted from the directive regardless of the application in which they were used. In 2011, a recast of the RoHS directive (RoHS2) was passed to set deadlines for eliminating exempt applications such as high lead (>85 % lead) alloys. These deadlines may only be extended through requests demonstrating that there are no acceptable alternatives. While there are no drop-in replacements for high lead solders, their use in a variety of applications has been eliminated and progress is being made on other application categories. As there is no proven reliable solution for some categories such as die attach and high temperature applications, it is likely that the European Union will extend the exempt for the use of high lead alloys but limit the scope of the exemption to those applications where no reliable alternative exists. Additionally, in light of the possible impending deadlines, there is an urgent need to conduct more studies to evaluate alternatives to high lead solder in different applications.