What causes dendritic growth?
Dendritic growth describes the formation of tree-like metallic filaments that bridge conductors, driven by ionic contamination, bias voltage, and moisture. Typical dendrites are copper or silver filaments that grow from an anode to a cathode, eventually shorting circuits.
Growth begins with anodic dissolution of metal at micro-defects, transport of metal ions through an electrolyte film, and cathodic deposition where conditions favor reduction. Halide ions accelerate dissolution and filament formation. Effective cleaning, humidity control, and conformal coatings mitigate risk.
Conditions for dendritic growth
Key conducive conditions:
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presence of soluble conductive ions such as chlorides or bromides
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continuous electrolyte film provided by humidity or condensation
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sustained electrical bias or polarization across conductors
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rough or damaged surfaces that promote local anodic sites
Dendrites form faster at higher humidity and temperature. ZESTRON’s reliability testing quantifies the time-to-failure under controlled conditions to set safe operating limits.
Prevention strategies
Preventive measures:
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rigorous cleaning to remove activators and salts
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use of low-residue fluxes and controlled process chemistries
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conformal coatings with validated adhesion and low ionic content
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design practices that increase creepage and clearance
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environmental control to limit humidity exposure
ZESTRON supplies cleaning chemistries and process optimization to reduce dendritic risk and supports design reviews for high-voltage and high-humidity products.