Abstract Microelectronic reliability requirements are tightening to a standard of near zero ppb defects due to the evolution of self-driving cars and wearable electronics. The successful transition from gold (Au) to copper (Cu) in wire-bonding introduces corrosion related reliability concerns to wire-bonded devices in integrated circuit (IC) packaging. This report studies the effect of bimetallic contact, Cu wire vs. aluminum (Al) bond pad, on the corrosion failure of Al bond pads when exposed to low ppm levels of chloride (Cl−) contamination. Real time corrosion screening was carried out on simulating Cu/Al micro patterns for time-dependent observation of corrosion progression in 5–20 ppm Cl− solutions at pH 5. Al in Cu/Al bimetallic couple corroded at accelerated rate compared to Al without bimetallic contact. Cathodic hydrogen evolution was found to be the key factor driving this aggressive Al bond pad corrosion under the influence of the peripheral Cu/Al bimetallic contact in acidic chloride solution. Chemically modifying the surface of Cu wires to prevent this H2 evolution reaction resulted in the inhibition of Al bond pad corrosion.

中文翻译：

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酸性氯化物环境下封装器件铜线键合失效机理研究

摘要 由于自动驾驶汽车和可穿戴电子设备的发展，微电子可靠性要求正在收紧到接近零 ppb 缺陷的标准。引线键合中从金 (Au) 到铜 (Cu) 的成功转变为集成电路 (IC) 封装中的引线键合器件引入了与腐蚀相关的可靠性问题。本报告研究了双金属接触、Cu 线与铝 (Al) 焊盘在暴露于低 ppm 水平的氯化物 (Cl−) 污染时对 Al 焊盘腐蚀失效的影响。对模拟 Cu/Al 微图案进行实时腐蚀筛选，以随时间观察 pH 5 下 5–20 ppm Cl− 溶液中的腐蚀进展。与没有双金属的 Al 相比，Cu/Al 双金属对中的 Al 以加速的速度腐蚀接触。发现阴极析氢是在酸性氯化物溶液中外围铜/铝双金属接触的影响下驱动这种侵蚀性铝焊盘腐蚀的关键因素。化学改性 Cu 线的表面以防止这种 H2 析出反应导致对 Al 焊盘腐蚀的抑制。