Kirsch Dylan J, Martin Joshua, Warzoha Ronald, McLean Mark, Windover Donald, Takeuchi Ichiro
Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
Rev Sci Instrum. 2024 Oct 1;95(10). doi: 10.1063/5.0213738.
Frequency Domain Thermoreflectance (FDTR) is a versatile technique used to measure the thermal properties of thin films, multilayer stacks, and interfaces that govern the performance and thermal management in semiconductor microelectronics. Reliable thermal property measurements at these length scales (≈10 nm to ≈10 μm), where the physics of thermal transport and phonon scattering at interfaces both grow in complexity, are increasingly relevant as electronic components continue to shrink. While FDTR is a promising technique, FDTR instruments are generally home-built; they can be difficult to construct, align, and maintain, especially for the novice. Our goal here is to provide a practical resource beyond theory that increases the accessibility, replicability, and widespread adoption of FDTR instrumentation. We provide a detailed account of unpublished insights and institutional knowledge that are critical for obtaining accurate and repeatable measurements of thermal properties using FDTR. We discuss component selection and placement, alignment procedures, data collection parameters, common challenges, and our efforts to increase measurement automation. In FDTR, the unknown thermal properties are fit by minimizing the error between the phase lag at each frequency and the multilayer diffusive thermal model solution. For data fitting and uncertainty analysis, we compare common numerical integration methods, and we compare multiple approaches for fitting and uncertainty analysis, including Monte Carlo simulation, to demonstrate their reliability and relative speed. The instrument is validated with substrates of known thermal properties over a wide range of isotropic thermal conductivities, including Borofloat silica, quartz, sapphire, and silicon.
频域热反射（FDTR）是一种通用技术，用于测量薄膜、多层堆叠结构以及界面的热性能，这些结构决定了半导体微电子器件的性能和热管理。在这些长度尺度（约10纳米至约10微米）下进行可靠的热性能测量，其中热传输物理和界面处的声子散射都变得越来越复杂，随着电子元件不断缩小，这种测量变得越来越重要。虽然FDTR是一项很有前景的技术，但FDTR仪器通常是自制的；它们可能难以构建、对准和维护，尤其是对于新手而言。我们的目标是提供一份超越理论的实用资源，以提高FDTR仪器的可及性、可重复性和广泛应用。我们详细介绍了未发表的见解和机构知识，这些对于使用FDTR获得准确且可重复的热性能测量至关重要。我们讨论了组件选择和放置、对准程序、数据收集参数、常见挑战以及我们在提高测量自动化方面所做的努力。在FDTR中，通过最小化每个频率下的相位滞后与多层扩散热模型解之间的误差来拟合未知的热性能。对于数据拟合和不确定性分析，我们比较了常见的数值积分方法，并且比较了多种拟合和不确定性分析方法，包括蒙特卡罗模拟，以证明它们的可靠性和相对速度。该仪器在包括硼浮法玻璃、石英、蓝宝石和硅在内的广泛各向同性热导率范围内，使用具有已知热性能的衬底进行了验证。
