塑封硅器件中介电薄膜的温湿效应分析(英文)

Environmental Effects on Dielectric Films in Plastic Encapsulated Silicon Devices

随着铜互连以及low-k电介质在超大规模集成电路中地广泛使用,low-k电介质的机械完整性及其对互连可靠性变得更加重要。影响介电膜的机械完整性和互连可靠性的因素包括介电膜的工艺制程,芯片与封装材料的相互影响,以及环境温度和湿度的影响。本文研究集中于了解环境温度和湿度对塑封硅器件中介电薄膜的可靠性影响。采用快速温度和湿度实验条件,对塑封硅器件中介电薄膜受水分和温度损伤的敏感性进行了分析。运用商业有限元(FEA)分析软件,对水分在塑封材料和硅器件中的扩散过程进行了建模及仔细分析。并对硅器件周边密封圈的防水分扩散效力进行了研究。通过这一系列实验与分析,对塑封硅器件中介电薄膜的温湿效应有了完整地了解,并提出和建立了相关的物理模型和经验公式。运用这物理模型和经验公式可对在各种使用环境温度和湿度条件下,塑封硅器件中介电薄膜的可靠性进行评估及分析。

Mechanical integrity of interlayer and intralayer dielectric films and its impact on interconnect reliability has become more important as critical dimensions in ultralarge-scale integrated circuits are continuously reduced and Cu interconnect, low-k dielectrics （Cu/low-k） are widely adopted for the new technology nodes. Mechanical integrity of the dielectric films and reliability of interconnect can be affected by the film deposition process, stresses from chip-packaging interaction （CPI） and environmental factors such as moisture and temperature exposure. In this study attention has been focused on understanding the moisture and temperature effects on reliability of dielectric films in plastic encapsulated silicon devices. Sensitivities to moisture and temperature induced damage in the dielectric films of the silicon devices were first evaluated using accelerated temperature and humidity stress conditions. Multiple stress conditions were used so the testing results could be applied to validate a physical acceleration model for the combined temperature and humidity stresses. Moisture diffusion in the silicon devices and their packages was then modeled using commercial Finite Element Analysis （FEA） software. Moisture sorption and diffusion properties of the packaging materials were also characterized to support the moisture diffusion modeling. Moisture distribution in the plastic package was analyzed for both the accelerated stress conditions and the product use or storage environmental conditions. The effectiveness of the peripheral seal ring on the silicon device as a moisture barrier was also investigated. Finally, reliability of the silicon devices under typical and extreme product use or storage environment conditions was assessed using the moisture distribution results and the validated acceleration model.