Authored By:
Kunal Shah, Ph.D.
LILOTREE
WA, USA
Summary
OEMs have started adopting sustainable materials and chemistry technologies for their electronics as a part of better ESG score rankings. Sustainability is becoming a key parameter for material and chemistry choices for the next generation electronics. The use of non-toxic options are being evaluated and preferred.
Several published data suggests the Potassium gold cyanide which is the primary gold salt in the standard immersion gold bath is well known to be a highly toxic substance and it may be fatal if swallowed, contacted or inhaled. It is highly toxic to the environment, especially to aquatic life. Every city/county across the world has allowable cyanide levels (ppm/ppb) in the wastewater regulations; there is a cost associated to bring the gold bath waste to wastewater regulation compliance. Also, mishandling of the gold salt or gold bath may lead to human health and/or environmental issues.
Moreover, recycling and reclaiming the existing precious metals present in the electronic waste is critical instead of resorting to mining these precious metals. The paper will talk about non-toxic (cyanide-free) immersion gold (reduction assisted) option which performs superior to legacy cyanide-based options in terms of stability of the solution and cost-effectiveness. Moreover, recycling and reclaiming of the precious metals/gold from the electronic waste will be discussed.
Conclusions
The novel Ni-free, cyanide-free surface finish offers a sustainable option for next generation electronic assemblies. The solderability results are successful after exhaustive conditions according to MIL-STD-883, method 2003. Also, the sustainable surface finish offers robust solder joints with better reliability compared to ENIG. It has a rose gold appearance and offers cost-savings by tight Gold thickness distribution and lower thickness. Moreover, the recycling and reclaiming the precious metals (i.e. Gold) will help source gold instead of traditional mining. This will promote sustainability and support ESG for OEMs.
Initially Published in the SMTA Proceedings
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