From Indium Corporation
Although lead-free soldering has been main stream in the industry since 2006
with the replacement of the eutectic SnPb system by the SnAgCu system, the
development of drop-in lead-free alternatives for high melting high lead solder
alloys is still far from mature. The BiAg alloy exhibits acceptable bulk strength,
but very poor ductility and wetting. Therefore, it is not acceptable as an option.
In this current work, a mixed-powder BiAgX solder paste system has been
developed as a viable alternative high temperature lead-free solder. The metal
powder in the paste is composed of a high-melting first alloy powder as a
majority and the additive powder as a minority. The additive contains a reactive
element to react with various metallization surface finishes. The additive will
melt and react on the parts before or together with the melting of the majority
solder. The reactive element in the additive is designed to be converted
completely into IMCs during the reflow process, resulting in a high-melting
solder joint. In the mixed-powder paste system, a melting temperature above
260°C was verified by both DSC and TMA data. The mixed-powder solders
show significantly improved wetting compared to Bi/11Ag. The voiding and
TCT performance are comparable with high-lead solders. The IMC layer
thickness of the mixed-powder system is insensitive toward thermal aging at
175°C while the high-lead solders show a considerable increase. The fine and
well-dispersed Ag particles in the joint, together with the controlled IMC
thickness, are attributed for the reliability improvement.
Products & Services
Topics of Interest
Lead-alloy solder will soon be banned from most electronics sold in Europe. Assemblers and PCB makers are learning how to cope. studied how lead-free solders would work with its surface-mounted...
Moving to Lead-Free Solder for Medical Electronics Microelectronics manufacturing worldwide is in a state of transition: from lead-based solder to lead-free solder. Over the next several years,...
The first step in choosing a solder is to decide what metals are going to be bonded, because the type of metal used will greatly influence the type of solder used. Soft solders are often used with...
Soldering uses alloys that melt below 840°F to join metals. Molten solder fills the space between surfaces to be joined, adheres to the surfaces, and solidifies. Electrical and electronic...
North America, the EU, and Japan are trying to eliminate lead from the printed-circuit-board (PCB) assembly process. Specifically, eliminating lead from soldering will and is having a huge impact on...