Correlating The Chemistry and Process With The Impurity, Structure and Properties of Electrodeposited Cobalt for Advanced Interconnects

半导体芯片中的金属线网络称为互连。这些电线连接晶体管并传输用于电路不同功能的电子信号。随着半导体器件尺寸的减小，最先进互连中铜的电阻率呈指数级增加。钴已成为替代铜的首选材料，它将推动半导体技术的进一步进步。然而，制造钴互连所需的化学和工艺仍在开发中，并且关于化学和工艺如何影响此类互连的结构和性能的信息不足。该奖项将提供基础研究来填补这一知识空白。该研究将重点关注电沉积中使用的有机添加剂如何实现钴互连的制造并控制钴中杂质的掺入。更重要的是，将以钴为例，以提供对电沉积金属中不同杂质元素如何影响金属的微观结构和电性能的一般了解。后者是先进器件制造应用的重要指标。该研究将用于在新的电化学学会学生分会中展示学生的研究活动。此外，还将为本科生电化学工程课程开发一个关于电沉积和微加工的新课程模块。用于铜互连制造的多组分有机添加剂之间的协同相互作用需要很长的孵化时间，并且在尺寸低于30 nm的互连结构方面面临挑战。另一方面，一种新发现的分子二肟会对钴沉积产生依赖于搅拌的强烈抑制。它使钴能够在结构底部优先生长，由于缺乏搅拌，电解质在该底​​部停滞。该项目采用二肟分子的各种衍生物来剖析这种抑制效应的机制以及不同的杂质如何融入沉积的金属中。此外，局部电极原子探针将结合电子显微镜技术和原位电学测量来了解不同杂质元素的分布及其对钴的微观结构演变和电阻率变化的影响。模板电沉积钴纳米线将用于表征小线的电迁移，而无需使用先进的光刻技术。

The network of metal wires in semiconductor chips are referred to as interconnects. These wires connect the transistors and carry the electronic signals for different functions of the circuitry. The resistivity of copper in state-of-the-art interconnects exponentially increases as the dimensions of semiconductor devices decrease. Cobalt has emerged as a top candidate among alternative materials to replace copper, and it will allow further advancement of semiconductor technology. However, the chemistry and processes that are needed for fabricating cobalt interconnects are still being developed, and there is insufficient information about how the chemistry and processing impact the structure and properties of such interconnects. This award will provide the fundamental research to fill this knowledge gap. The research will focus on how organic additives used in electrodeposition enable the fabrication of cobalt interconnects and control the incorporation of impurities in cobalt. More importantly, cobalt will be used as an example to provide a general understanding of how different impurity elements in electrodeposited metals impact the microstructures and electrical properties of the metal. The latter are important metrics for applications in advanced device fabrication. The research will be used to showcase student research activities in a new Electrochemical Society student chapter. In addition, a new class module on electrodeposition and microfabrication will be developed for an undergraduate level electrochemical engineering course.The synergistic interactions between multi-component organic additives that have been used in copper interconnect fabrication requires a long incubation time and faces challenges for interconnect structures with dimension below 30 nm. On the other hand, a newly discovered molecule, dioxime, results in an agitation-dependent strong suppression on cobalt deposition. It enables the preferential growth of cobalt at the bottom of the structure, where the electrolyte is stagnant, due to the lack of agitation. This project employs various derivatives of dioxime molecules to dissect the mechanisms of such suppression effects and how different impurities become incorporated into the deposited metals. Furthermore, local electrode atom probe will be used in conjunction with electron microscopy techniques and in-situ electrical measurements to understand the distribution of different impurity elements as well as their impacts on the microstructure evolution and resistivity change of cobalt. Template electrodeposited cobalt nanowires will be used to characterize electromigration of small lines without the use of advanced lithography techniques.