Tin Whisker Formation Prevented with ALD Nanolaminate Coating
Picosun reports that the hermetic encapsulation using ALD nanolaminates that it developed has been proven to block tin whisker formation on PCB assemblies completely. In a collaborative project with the European Space Agency, Poltronic Ltd, and Loughborough University in the UK, over several years, the encapsulation using ALD nanolaminates was shown to block tin whisker formation over an extended period of time. (See ESA image of tin whiskers above, Copyright ESA, CC BY-SA 3.0 IGO)
During the observation period of over one month to three years, the ALD-protected samples showed no tin whisker growth at all. However, on non-protected samples, researchers measured a tin whisker density of over 1000 pcs/cm2.
Picosun says that in addition to blocking tin whiskering, its ALD nanolaminates help to protect the PCBAs against other fundamental degradation phenomena including various forms of corrosion and oxidation. Furthermore, its hermetic ALD coating works efficiently even against moisture and gaseous sulfur in a polluted atmosphere, according to the company. Due to the coating's nanometer-scale thickness, it has no effect on the PCBA functionality, mass or dimensions, and it allows reworking of the PCBA.
Drop of salt water on 1mm-Ag coated electrodes with 3.3V bias (see publication 2.) (Click image to enlarge)
Tin whisker formation and corrosion are especially disastrous in several high-reliability electronics applications including data centers, aviation, space, military, medical, and industrial control systems. Picosun asserts that its ALD encapsulation method now improves safety, lengthens product lifetime, and provides long-term cost savings.
Picosun offers P-1000 and P-300B high volume batch ALD systems that it says can achieve fast, cost-efficient processing of large amounts of PCBAs with production-proven, industry-optimized processes.
"We are happy to announce these groundbreaking results obtained with our ALD encapsulants in protection of specialty electronics. This is a new, potentially huge market for ALD. There has already been lots of interest towards our turn-key coating solutions for large scale PCBA protection from the corresponding industries. This shows again the versatility of ALD and its power to disrupt near all fields of today's industrial manufacturing," says Dr. Jani Kivioja, CTO of Picosun Group.
Picosun's collaboration project with the European Space Agency (ESA):
- "Evaluation of Atomic Layer Deposition (ALD) Conformal Coating to Mitigate Tin Whiskering" (4000113005/14/NL/PA), 2015-2018.
- "AtomicLayer Deposition for Tin Whiskers Mitigation and Cure on Space Electronics Manufacturing" (4000122745/18/NL/LvH/gp), launched in 2018 and continuing.
