RII Track-4:@NASA: Investigation of Two-Phase Aerosol Formation, Transport, and Deposition in Aerosol Jet Printing for Submicron Manufacturing of Printed Electronic Devices

该项目将为马歇尔大学研究公司(马歇尔)的一名助理教授和一名研究生提供奖学金，与阿拉巴马州美国宇航局马歇尔航天飞行中心的研究人员合作进行研究。通过该奖学金，PI旨在确定气雾剂喷墨打印空气动力学背后的关键现象，这些现象会影响材料沉积，从而影响设备制造的分辨率。美国半导体行业是主要的经济驱动力，占美国制造业的10%，每年为美国经济贡献超过2,500亿美元的价值。半导体设备支持广泛的应用，如第五代(5G)通信、人工智能、高性能计算、安全和本地/遥感。物联网等商业市场显著增加了对基于半导体的产品的需求。此外，新的、功能更强大的技术的快速采用正在推动美国对更多半导体产能的需求。此外，为了满足当今的性能特征，如低功耗、快速切换速度和更高的计算能力，对“高分辨率”器件制造的需求日益增长。喷雾打印(AJP)作为一种高分辨率、直接写入的制造方法已经出现，用于制造诸如传感器、光电子器件和细间距电子器件等广泛的电子产品。然而，尽管最近在AJP技术和新型功能材料的配方方面取得了进展，但“亚微米”电子器件的制造遇到了严重的挑战，这主要是由于AJP工艺潜在的物理基础背后的内在局限性和复杂性。因此，迫切需要确定支配物理现象和AJP分辨率之间的联系，以超越当今的限制制造亚微米器件。该项目的长期目标是促进亚微米直写印刷电子器件的制造。为了实现这一目标，该项目的总体目标是确定AJP空气动力学背后的关键现象，这些现象影响材料沉积的分辨率，并最终影响器件制造。拟议的研究计划基于先进的计算流体力学(CFD)模型，随后在NASA马歇尔航天飞行中心对气溶胶沉积的分辨率进行了实验表征。计算模型不仅包括具有不同气溶胶处理机制的AJP沉积头的三维几何形状，而且还包括湍流气溶胶的雾化、输送和沉积过程。这一研究项目的贡献将是重大的，因为它预计：(I)确定影响特征尺寸的关键空气动力学现象，从而确定AJP中材料沉积的分辨率，以及(Ii)为亚微米直写制造半导体电子器件(目前尚不可行)铺平道路。该项目将显著提高美国的器件制造能力，加强美国半导体产业，从而有助于增强国家繁荣、安全和美国在制造业中的领导地位。此外，NASA将能够在已建立的AJP空气动力学计算模型和实验观测的基础上设计、制造和测试新型AJP沉积头。此外，该项目将减少限制直写加法制造的科学障碍，并将催化今天尚未实现的新制造能力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will provide a fellowship to an Assistant professor, and a graduate student at the Marshall University Research Corporation (Marshall) to conduct research in collaboration with researchers at the NASA Marshall Space Flight Center in Alabama. Through the fellowship, the PI aims to identify the key phenomena behind the aerodynamics of aerosols jet printing that affect material deposition and thus the resolution of device fabrication. The U.S. semiconductor industry is a major economic driver, making up 10% of the nation's manufacturing sector and contributing over $250 billion a year in value to the U.S. economy. Semiconductor devices support a wide range of applications, such as fifth-generation (5G) communications, artificial intelligence, high-performance computing, security, and local/remote sensing. Commercial markets, such as the Internet-of-Things, have significantly increased the need for semiconductor-based products. Also, the rapid adoption of new, more powerful technologies is driving demand for additional semiconductor production capacity in the U.S. Additionally, there is a burgeoning need for "high-resolution" device fabrication to fulfill today's performance characteristics, such as low power consumption, fast switching speeds, and increased computing power. Aerosol jet printing (AJP) has emerged as a high-resolution, direct-write manufacturing method for fabrication of a broad spectrum of electronics, such as sensors, optoelectronic devices, and fine-pitch electronics. However, despite recent advances in the AJP technology and formulation of novel functional mate-rials, "submicron" fabrication of electronic devices has encountered serious challenges due largely to the intrinsic limitations and complexity behind the underlying physics of AJP process. There is, therefore, a critical need to identify the link between the governing physical phenomena and the resolution of AJP toward submicron device fabrication beyond today's limits.The longterm goal of this project is to contribute toward submicron direct-write fabrication of printed electronic devices. In pursuit of this goal, the overall objective of the project is to identify the key phenomena behind the aerodynamics of AJP that affect the resolution of material deposition and ultimately device fabrication. The proposed research plan is based on advanced computational fluid dynamics (CFD) models, followed by experimental characterization of the resolution of aerosol deposition carried out at NASA's Marshall Space Flight Center. The computational models include not only the 3D geometry of various AJP deposition heads with different aerosol handling mechanisms, but also the processes of turbulent aerosol atomization, transport, and deposition. The contribution of this research project will be significant because it is expected: (i) to identify the key aerodynamic phenomena influencing feature size and therefore the resolution of material deposition in AJP, and (ii) to pave the way for submicron direct-write fabrication of semiconductor electronic devices (not feasible today). This project will significantly enhance the device fabrication capability of the U.S., will strengthen the U.S. semiconductor industry, and consequently will contribute to the enhancement of national prosperity, security, and U.S. leadership in manufacturing. In addition, NASA will be able to design, manufacture, and test novel AJP deposition heads on the basis of the established computational models as well as experimental observations of the AJP aerodynamics. Furthermore, this project will reduce the scientific barriers that limit direct-write additive manufacturing and will catalyze new manufacturing capabilities that have not been materialized today.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.