Mechanistic Investigation and Prevention of Al Bond Pad Corrosion in Cu Wire Bonded Device Assembly
Heavy corrosion on aluminum (Al) bond pads, with a “mud-crack” appearance, in a copper (Cu) wire-bonded assembly can be a critical failure mode, especially under harsh conditions such as automotive environments. This corrosion can be associated with the presence of contaminants such as chloride ions (Cl-). However, the exact corrosion activation mechanism remains unclear and hence the effective corrosion prevention cannot be achieved. In this report, a novel immersion corrosion screening metrology was utilized as an in situ characterization tool to establish the corrosion mechanism directly relevant to Cu wire-bonded devices. With this improved understanding of Al bond pad corrosion mechanism, severe Al pad corrosion can be prevent with a corrosion inhibitor coating. The corrosion inhibitor coating remains stable at 260 oC annealing. Preliminary failure analysis on molded devices showed corrosion inhibitor coating is highly effective in prevent chloride related Al pad corrosion.
Tuesday, June 13, 2017, 8 a.m.–5 p.m. ET
Atlanta, GA, United States