Abstract

Recently a phenomenon has been found that shows different corrosion rates over Al bond pad regardless of different densities of Cl, F components on Al bond pads in different products. According to the results of analysis, the products showed different corrosion rates for different etch conditions of the bond pad opening. For the cause analysis, we conducted a cross-sectional profile comparison between two products with Al bond pads. Based on the result of comparison, we discovered that the side wall profile of the Al bond pad is affected by the etch conditions of the bond pad opening. In some severe cases, it was observed that a small void was formed between the side wall and Al bond pad. Under moist conditions, this void provided moisture between Al bond pad and TiN barrier metal that the electricity contacted. Through this study, we could conclude that the moisture in the void between Al bond pad and TiN barrier metal may create a galvanic corrosive condition.

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