Heraeus lead-free solder is IDEAL for Marconi

Citation

(1999), "Heraeus lead-free solder is IDEAL for Marconi", Microelectronics International, Vol. 16 No. 3. https://doi.org/10.1108/mi.1999.21816cab.020

Heraeus lead-free solder is IDEAL for Marconi

Heraeus lead-free solder is IDEAL for Marconi

Keywords Heraeus, Solder paste

Marconi Communications has demonstrated one of Europe's first environmentally driven lead-free assembly lines using standard production machinery and lead-free solder paste from leading supplier Heraeus.

The line at Marconi Communications' facility in Coventry was demonstrated recently to a large industry consortium and forms a key part of Marconi Communications' environmental IDEALS Programme.

The IDEALS Programme is a pioneering EC funded project which was designed to evaluate the feasibility of lead free soldering and subsequently to develop a solder that would provide an increase in service life.

The production line at Marconi Communications is an existing "work horse" SMT line that has not been optimised in any way for the use of lead-free. It comprises a screen printer, two placement machines and an eight zone convection reflow oven. It is believed to be the first lead-free line in Europe designed specifically for compliance to environmental concerns and the proposed EU Waste in Electronics and Electrical Equipment (WEEE) directive that could ban the use of lead entirely from European electronics assembly processes and PCBs by 1 January 2004.

Other European manufacturers running lead-free lines are currently doing so to take advantage of associated benefits offered by lead-free's higher temperature performance.

The project draws heavily on the newly developed F365 Series lead-free solder paste and in-depth expertise supplied by Heraeus. It is also a typical example of the long-term partnership Heraeus strives to form with its customers in order to understand and meet their real needs.

The F365 paste is based on a unique tin-silver-copper (Sn4AgO.5Cu) alloy mixed with a state-of-the-art halide-free no-clean flux. The paste provides superior performance on a variety of surface finishes and excellent print-to-print consistency. It also leaves a low, clear flux residue with low ionic contamination and high SIR, and can be reflowed under air or an inert atmosphere.

"This latest project fully verified what it set out to determine", said Marconi Communications' materials technology manager, Gerry Andrews. "First, that assembling PCBs using a lead-free solder paste can be entirely suitable electrically and that the performance of the boards can indeed be improved by using a lead-free process. Namely that lead-free boards offer improved thermo-mechanical reliability in terms of the fatigue characteristics of soldered joints."

The PCBs used in the demonstration featured an immersion silver and gold over nickel lead-free finish, and used a wide range of standard components from PLCCs to chip capacitors and resistors, along with fine-pitch SMT devices down to 20-thou.