水汽侵入对Cu互连电迁移性能退化的影响机理

Influence Mechanism of Moisture Invasion on Electromigration Performance Degradation of Cu Interconnection

随着超大规模集成电路(VLSI)工艺的发展及低介电常数(k)材料的引入,芯片及测试结构对于水汽侵入的影响愈加敏感,从而对Cu互连可靠性测试的准确性提出了严峻的挑战。通过设计的实验验证了水汽侵入对Cu互连电迁移性能退化的影响。借助失效分析手段,深入研究和讨论了水汽侵入的潜在影响机制。实验分析表明,水汽侵入对Cu互连的影响主要集中在使Cu互连金属自身发生氧化或使Ta/TaN金属阻挡层发生氧化两方面。基于该研究结果,提出了防止水汽侵入影响的有效措施,其对于保障Cu互连可靠性测试及集成电路制造工艺可靠性评估的准确性具有参考作用。

With the development of very large scale integration(VLSI)technology and the introduction of low dielectric constant(k) materials, chips and test structures are more and more sensitive to the influence of moisture invasion, which poses a severe challenge to the accuracy of Cu interconnection reliability test.Through the designed experiments, the influence of moisture invasion on degradation of electromigration performances of Cu interconnection was verified.The potential influence mechanism of moisture invasion was deeply studied and discussed by means of failure analysis.The experimental analysis shows that the influence of moisture invasion on Cu interconnection mainly focuses on two aspects, the oxidation of Cu interconnection metal itself or the oxidation of Ta/TaN metal barrier layer.Based on the research results, the effective measures to prevent the influence of moisture invasion were proposed, which had a referenfce role in ensuring the accuracy of Cu interconnection reliability test and integrated circuit manufacturing process reliability evaluation.