FAW: In Situ Elucidation of Reaction Pathways During Low Pressure Chemical Vapor Deposition

现代计算机的计算速度受到用于连接设备的亚微米金属线的电阻的限制。解决互连效率低下问题的一种方法是分层设备之间的垂直互连，这是三维集成的关键。由于传统的集成电路制造是二维过程，没有方法开发出垂直亚微米直径的“导线”。这种电子升降机可以通过选择性金属沉积工艺制成，即材料催化其自身沉积，在绝缘材料中填充井。选择性损失（LOS），导致金属线之间短路，是由于与非催化绝缘体的反应，气相反应，绝缘体上的成核和沉积，以及沉积反应中活性中间体之间的化学反应。寻找过程边界是一个了解所有的化学途径和相关的运输过程的问题，包括多相和均相反应。LOS动力学是相当复杂的反应物种，有很短的寿命，只能看到与原位诊断。这项研究的目标是回答一些在商业或特高压反应堆中无法回答的非常具体的问题。热扩散和再循环在LPCVD反应器中的作用是什么？选择性CVD过程中的气相中间体、反应和产物是什么？我们的LPCVD （1 torr）结果与我们在由NSF资助的UHV研究中确定的结果相比如何？从长远来看，这项研究将有助于了解哪些其他反应物可以用来制造选择性沉积的垂直电线，以及根据局部成分和温度，工艺边际是多少。一旦了解了选择性沉积的局部条件，就有必要实施商业反应器的数学模型，以便确定导致所需近晶圆成分的入口气体成分。这个全局模型还必须包括亚微米内填充时的瞬态建模。目前的模型将扩展到新的化学物质。

The computation speed of modern computers is limited by the resistance of the submicron metal lines used to interconnect devices. One solution to the problem of inefficient interconnect is a vertical interconnect between layered devices, a key to 3-D integration. Because IC fabrication is traditionally 2-D procedure, no method has been developed to create vertical submicron diameter "wires". This electron elevator could be made by a selective metal deposition process whereby a material catalyzed its own deposition, filling a well in an insulating material. Loss of selectivity (LOS), leading to shorts between metal lines, is due to reaction with the noncatalytic insulator, gas phase reactions, nucleation and deposition on the insulator, and chemistries between reactive intermediates from the deposition reaction. Finding the process margin is a matter of understanding all of the chemical pathways and relevant transport processes of both the heterogeneous and homogeneous reactions. The LOS kinetics are quite complex for the reactive species, have very short lifetimes, and can only be seen with in situ diagnostics. The goal of the research is to answer some very specific questions which cannot be answered in commercial or UHV reactors. What is the role of thermodiffusion and recirculation in LPCVD reactors? What are the gas phase intermediates, reactions, and products during selective CVD? How do our LPCVD (1 torr) results compare with those we determine in the UHV studies funded by NSF? Over the long term, the research will lead to understanding what other reactants could be used to create selectively deposited vertical wires and what the process margins are in terms of local composition and temperature. Once the local conditions are known for selective deposition, it becomes necessary to implement mathematical models of commercial reactors so that the inlet gas composition which results in the desired near wafer composition can be determined. This global model must also include modeling of the transience within the submicron well as it fills. Current models will be extended to new chemistries.