New Metallization Precursors for Microelectronic applications

微米和纳米制造是微电子、光伏和显示技术的基石，它在很大程度上依赖于使用化学气相沉积(CVD)和原子层沉积(ALD)的薄膜沉积。金属薄膜作为微电子学中使用的布线(即金属互连)尤其重要，但也用作电触点和光电子学。*随着微电子学的进一步小型化，ALD变得越来越重要：它可以处理现代电子设备的长度尺度(10 Nm)，比包括CVD在内的其他制造技术要好得多。ALD的沉积过程在很大程度上依赖于挥发性的、含金属的“前体”化合物的化学成分，以在汽相中传递目标薄膜的成分。为了满足ALD要求的挥发性和热稳定性，不断需要新型的化学前驱体。*自1997年以来，铜一直是微电子中的互连金属选择，但随着这种布线的横截面缩小以容纳更小、更密集的晶体管和其他设备，铜已经开始失效。铜金属在小互连尺寸的电流通量中容易电迁移，*这项拟议的研究将探索一种框架，以准确和可重复地测量这两个关键的热参数(挥发和热分解)，并建议使用这些参数来定义前体的“热范围”：在该温度范围内，前体具有足够高的蒸汽压力，可用于ALD过程，而不会在蒸汽前体的输送或气体-表面界面上进行热分解。*提出了三个中期项目：开发用于传感和光谱分析等光子应用的金和银薄膜的前驱体；开发镍和钴的前体，作为铜的短期替代品；以及开发钨和钼的前体，作为未来互连技术的高温、高凝聚力的金属。*这些前驱体将设计成具有单阴离子、螯合配体(酰胺、胍酸盐、亚胺基吡咯烷酸酯、双酮酸酯)、单阴离子、单齿配体(酰胺、烷基)和配位配体(膦、卡宾)。这些设计将用它们的有效“热范围”进行比较，并进行比较，以调查每个配体在设计中的有效性。“挥发性开始”和“热分解”温度的标准定义将被用来比较它们。迭代前体设计将用于开发和改进候选前体，最有希望的候选将用于开发ALD工艺。**

Micro- and nano-fabrication, the cornerstone of microelectronics, photovoltaics, and display technology relies greatly on the deposition of thin films using chemical vapour deposition (CVD) and atomic layer deposition (ALD). Metal thin films are particularly important as the wiring (i.e., metal interconnects) used in microelectronics, but also as electrical contacts and for optoelectronics.***As microelectronics becomes further miniaturised, ALD has become increasingly important: it can handle the length scales (10 nm) of modern electronics much better than other fabrication techniques including CVD. Deposition processes by ALD rely heavily on the chemistry of volatile, metal-containing “precursor” compounds to deliver the components of the target film in the vapour phase. Novel chemical precursors are continually required to match the volatility and thermal stability required by ALD.***Copper has been the interconnect metal of choice in microelectronics since 1997, but as the cross-section of this wiring has shrunk to accommodate smaller, more densely packed transistors and other devices, copper has started to fail. Copper metal will easily electromigrated in a current flux at small interconnect dimensions, causing poor conductivity and ultimately poor reliability.***The proposed research will explore a framework in which to accurately and reproducibly measure these two key thermal parameters (volatilization and thermal decomposition) and proposes to use these to define the “thermal range” of a precursor: the temperature range over which the precursor has a high enough vapour pressure to be useful in ALD processes without thermally decomposing either in the delivery of the vapour precursor or at the gas-surface interface.***Three medium-term projects are proposed: the development of precursors for gold and silver thin films for use in photonic applications like sensing and spectroscopy; the development of nickel and cobalt precursors as near-term replacements for copper as an interconnect material; and the development of precursors for tungsten and molybdenum, as high-temperature, high cohesion metals for future interconnect technology. ***These precursors will be designed with monoanionic, chelating ligands (amidinates, guanidinates, iminopyrrolidinates, diketiminates), monoanionic, monodentate ligands (amides, alkyls) and coordinative ligands (phosphines, carbenes). The designs will be compared using their effective “thermal range” and compared to investigate the effectiveness of each ligand in the design. Standard definitions of the temperatures for the “onset of volatility” and “thermal decomposition” will be used to compare them. Iterative precursor design will be used to develop and improve candidate precursors, and the most promising candidates will be used to develop ALD processes.**