In-Situ Film Thickness and Stress Measurement Using Infrared Sensing

本课题提出了一种测量薄膜厚度的新方法。非破坏性，非接触式红外成像系统与位于感兴趣的薄膜层内部或下方的交流热源同步。选择交流方法来利用差分方案，实现高分辨率厚度测量。该方法为薄膜涂层厚度的测量提供了一种新的工具，具有重要的研究和技术意义。初步实验表明，该方法完全适用于测量几微米到毫米范围内的薄膜厚度。本提案旨在通过利用辐射传热方案将该方法扩展到纳米厚膜。该实验方法可应用于生产环境中，实现薄膜沉积过程的闭环反馈控制。该方法也适用于高通量生产环境的质量控制。因此，所提出的实验方法将显著改善涂层工艺，并显著减少提高涂层性能和可靠性所需的时间和费用。利用该计划开发的红外传感技术，可以在涂层过程的任何阶段（沉积期间和/或制造后）量化薄膜厚度、完整性和应力。由于目前的技术主要基于经验处理研究和事后破坏性评估，因此原位监测薄膜厚度的能力对于许多应用来说是至关重要的。再加上对应力进行量化的能力，该方法对薄膜加工和表征技术做出了重大贡献。所提出的方法可用于广泛的工业应用，包括（但不限于）：微电子制造和组装，MEMS制造和性能，能量转换工业中使用的热障涂层，玻璃上的金属涂层，以及从飞机到手机的所有油漆或保护涂层。

The proposed research project presents a new method for measuring the thickness of thin films. A non-destructive, non-contacting infrared imaging system is synchronized to an AC heat source located within or below the film layer of interest. An AC approach is chosen to exploit differencing schemes that enable high-resolution thickness measurements. The proposed method provides a new tool for measuring the thickness of film coatings with implications in both research and technology. Preliminary experiments have shown that the proposed method is perfectly suitable for measuring film thickness in the range of several microns to millimeters. This proposal aims to extend the method to nanometer thick films by utilizing a radiative heat transfer scheme. The proposed experimental method can be implemented into a production environment for closed-loop feedback control during film deposition. The method is also amenable to quality control in high throughput production environments. As such, the proposed experimental method will significantly improve coating processes and dramatically decrease the time and expense required to improve coating performance and reliability.Using the infrared sensing technology developed in this program, film thickness, integrity and stress can be quantified at any stage of the coating process, both during deposition and/or after manufacture. The ability to monitor film thickness in-situ is a critical need for many applications, as current techniques are based largely on empirical processing studies and post-priori destructive evaluation. Add to that the ability to quantify stress and the method emerges as a significant contribution to the technology of thin film processing and characterization. The proposed method can be used in an enormous range of industrial applications, including (but not limited to): microelectronic fabrication and assembly, MEMS fabrication and performance, thermal barrier coatings used in the energy conversion industry, metallic coatings on glass, and paint or protective coatings in everything from airplanes to cell phones.