Transition to lead free soldering - a great change for a better understanding of materials and processes and green electronics

The lead ban in electronics - enforced by environmental concerns and legal reality by 2006 through RoHS directive has initiated a broad rethinking towards eco/sup 2/-efficiency (economical and ecological) of interconnection technology its materials and processes. The implementation of lead free soldering however is not a drop-in process. In order to secure the production of high quality and reliable lead free products with low environmental burdens by 2006 there are still various technological issues to be solved. This paper gives an overview of environmental (e.g. toxicity and energy demand) and technological issues (e.g. higher thermal stress, whisker formation) deriving from the implementation of lead free soldering processes. It is shown which technological innovations have been initiated through a better understanding of interconnection materials and processes. Substitution of lead in the interconnection system is just the first step to green electronics. The next step is the wise selection of an alternative system and technology based on a profound understanding of the ecological and economical facts.

Introduction

Since the beginning of the 1990s the application of lead in electronics has been critically discussed. In the next years lead in many electronic products will be banned in several regions driven by legislation in Europe [1] and China, but also by market and technical requirements.