IPC-2901 : 2018

1 INTRODUCTION

1.1 The European Union’s Restriction of Hazardous Substances (RoHS) legislation [1], which went into effect July 2006, has had a profound impact on the electronics industry. One of the restricted substances, lead (Pb), is commonly used in alloys with tin for component finishes, printed board finishes and solders. While a great deal of historical knowledge exists relating to tin-lead (Sn-Pb) based electronic systems and products, the rapid transition of the electronics industries towards Pb-free (hereon denoted as Pb-free) has altered that experience base. Unless otherwise indicated, SnPb in this document refers to eutectic 63Sn37Pb solder systems.

Pb-free materials directly affect product performance, reliability and service life in many ways. There have been numerous, documented failures of electronics due to Pb-free materials in both commercial and Aerospace, Defense and High Performance (ADHP) products. The failure mechanisms for Pb-free materials are significantly different than SnPb based materials [2, 3]. Some failure mechanisms have not been experienced before. The ADHP industry has tried to avoid the use of Pb-free materials to the extent possible but the cost for doing so is increasing for product design, materials and manufacturing. It is currently cost prohibitive to require SnPb for all Commercial Off the Shelf (COTS) parts and assemblies used in ADHP products. Eventually it will become more affordable to incorporate Pb-free technology as the knowledge base improves. When Pb-free solders are used for ADHP electronics hardware, controls should be implemented in accordance with IPC J-STD-001 and its related Space Applications Electronic Hardware Addendum.