Materials for surface mount reflow soldering

Reflow soldering is now a widely spread technology for soldering of surface mount semiconductor packages. For some of the newer semiconductor packages, such as a Ball Grid Array (BGA), reflow soldering is the only suitable method.

This application note describes the materials for reflow soldering: the Printed-Circuit Board (PCB), semiconductor packages and solder paste. One of the key features of the PCB is the footprint design. The footprint design describes the recommended solder land on the PCB to make a reliable solder joint between the semiconductor package and the PCB. A proven solder material is SnPb, but due to legislation, the industry has changed, to a large extent, to Pb-free solutions such as Sn/Ag/Cu (SAC). Process requirements for solder paste printing and reflow soldering, for SnPb and Pb-free, are also discussed in this application note. This document concludes with sections on inspection and repair and component handling.

View the PDF document for more information.

Originally published by NXP Semiconductors at www.nxp.com as "Surface mount reflow soldering".