Lead-free Solders in Electronics

Introduction

In recent years, effort to develop alternatives to lead-base solders have increased significantly. One popular notion is to use lead-free solder as a way to eliminate one of the most harmful chemicals from manufacturing outflow.
Development of the lead-free soldering material was promoted by various government agencies in Europe, Japan and U.S.
Numbers of the lead-free alloys for soldering have been short listed to include Sn/Ag/Cu, Sn/Ag/Bi, Sn/Ag and many others. However, increase demand on finite resources such as bismuth and silver compare to other metals will impact prices of these raw materials. Finding of a new Lead-Free alloy was imminent due to overall cost impact on the soldering process as well as associated equipment and parts.

Some industries have already eliminated lead and have found suitable alternatives, for example plumbing solders, tinned cans, lead-free gasoline for vehicles, and lead-free cut crystal glass.

Now, a new type of lead-free soldering material is available with low melting temperature (around 199°C and required peak temperature is 215°C) and costs much less than Sn/Ag/Cu alloy. This soldering material has been recognized by many large semiconductor companies and the test results show very positive sign as “Drop-In”.
Well-known major electronic manufacturer has already applied the Sn/Zn/Al solder to their electronic consumer product (picture shown below, Sn/Zn/Al soldered PCB on Liquid Crystal Display) and it is available on the consumer market.

Printed Circuit Board with Sn/Zn/Al solder
used on LCD