EAGER: Scanning Ultrasound Probe for Semiconductor Sub-Surface Metrology

非技术：迫切需要在表面以下的纳米尺度上对半导体器件进行成像。这将使其有可能在二维和三维结构（如微机电系统（MEMS））中识别隐藏的缺陷并进行故障分析。当前的纳米级次表面成像技术需要大量的样品制备，非常慢，并且需要昂贵的设备。或者他们根本无法对不透明的样品成像。该解决方案是一种以合理的成本提供掩埋缺陷的非破坏性、高通量纳米级成像的工具。该项目将结合联合收割机扫描探针显微镜与超声全息术，以纳米级分辨率在三维空间中揭示和表征地下特征。在这项技术中，悬臂监测沿着表面传播的声波。对这些波的振幅和相位的扰动携带了关于地表之下和附近结构的信息。这些变化被检测为频率和相位的微小差异，从而导致由悬臂检测到的拍频。然后，这些变化被用来创建由表面下和近表面的功能和缺陷产生的空间映射作为悬臂扫描整个表面。最终目标是将扫描探针显微镜硬件与功能电子器件集成到现场可编程门阵列，可配置的集成电路中。该项目有望为半导体器件和结构的无损成像开辟新的前景。一旦开发出来，该技术将提供给其他机构，扩大用户基础，包括物理科学，工程和相关领域。PI将把该项目的成果整合到本科课程中，并强调工程和物理科学原理如何影响材料和器件研究。通过科学芝加哥计划，将通过对小学的课堂访问促进代表性不足的群体的积极参与。技术：半导体行业迫切需要创新的成像模式。这些都是特别需要的，以确定埋缺陷和分层，并提供在二维和三维结构的故障分析。这些包括基于微机电系统（MEMS）和互连的设备。本项目将开发用于次表面检测和失效分析的“扫描厚度共振声学显微镜”。目前的纳米级亚表面成像技术不能探测光学不透明的样品，或者需要大量和耗时的样品制备，非常慢，并且需要昂贵的计量设备。该解决方案是一种工具，它提供了非破坏性的，高通量的纳米级成像的掩埋缺陷，并可以广泛部署在多个点的研究和开发周期，在一个合理的成本。预期的应用将确定埋在半导体，MEMS和低K电介质材料在2D和3D几何结构的纳米结构。这项创新技术将带来变革性的研究，以识别纳米级分辨率的复杂三维器件和结构几何形状中的2D和3D材料堆栈中的失效分析和隐藏缺陷。在这项技术中，悬臂监测表面声波的扰动，特别是它们的相位，其携带关于由于它们各自的粘弹性性质的差异而在样本声波的散射中反射的嵌入或掩埋的子结构的信息。由于亚表面纳米结构/缺陷的存在而引起的体波的振幅和相位的变化以及近表面的变化影响由悬臂检测的差频信号（拍频）的振幅和相位。这些变化用于创建由表面下和近表面特征/缺陷生成的空间映射。为了实现这些努力需要一种方法来结合联合收割机扫描探针显微镜硬件，功能电子及其集成到现场可编程门阵列的同时生成和检测多个harmonics.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Non-technical:There is an acute need to image semiconductor devices at nanometer scales below the surface. This will make it possible to identify buried defects and perform failure analysis in two- and three-dimensional structures such as micro-electromechanical systems (MEMS). Current nanoscale subsurface imaging techniques require extensive sample preparation, are exceptionally slow, and require expensive equipment. Or they are simply unable to image opaque samples. The solution is a tool which provides non-destructive, high throughput nanoscale imaging of buried defects at a reasonable cost. This project will combine scanning probe microscopy with ultrasound holography to reveal and characterize subsurface features with nanoscale resolution in three dimensions. In this technology, a cantilever monitors acoustic waves that travel along the surface. Perturbations to the amplitude and phase of these waves carry information about structures beneath and near the surface. These variations are detected as small differences in frequency and phase, resulting in beats that are detected by the cantilever. These variations are then used to create spatial mappings generated by subsurface and near-surface features and defects as the cantilever scans across the surface. The ultimate aim is to integrate scanning probe microscopy hardware with functional electronics into field-programmable gate arrays, configurable integrated circuits. The project promises to open new vistas in non-destructive imaging of semiconductor devices and structures. Once developed, the technology will be made available to other institutions, broadening the user base to include physical sciences, engineering and related fields. The PI will integrate results from this project into undergraduate courses and highlight how the principles of engineering and physical science impact materials and device research. Active participation of underrepresented groups will be promoted through classroom visits to elementary schools through the Science Chicago program.Technical:There is an acute and timely need for innovative imaging modalities in semiconductor industries. These are especially needed to identify the buried defects and delamination and provide failure analysis in both two- and three-dimensional structures. These include devices based on micro-electromechanical systems (MEMS) and interconnects. This project will develop "Scanning Thickness Resonance Acoustic Microscopy" for sub-surface inspection and failure analysis. Current nanoscale subsurface imaging techniques are unable to probe optically opaque samples or require extensive and time consuming sample preparation, are exceptionally slow, and require expensive metrology equipment. The solution is a tool which provides non-destructive, high throughput nanoscale imaging of buried defects, and that can be widely deployed at multiple points in the research and development cycle, at a reasonable cost. Anticipated applications will identify buried nanostructures in semiconductor, MEMS, and low-K dielectric materials both in 2D and 3D geometries. This innovative technology will bring transformative research in identifying the failure analysis and buried defects both in 2D and 3D materials stacks in complex three-dimensional devices and structural geometries with nanometer scale resolution. In this technology, the cantilever monitors the perturbation to the surface acoustic waves, especially their phase, which carry information about embedded or buried sub-structures reflected in the scattering of specimen acoustic waves due to the difference in their respective viscoelastic properties. Variations in the amplitude and phase of the bulk wave due to the presence of the sub-surface nanostructures/defects as well as the variations in near surface affect the amplitude and the phase of the difference frequency signal (beats) which is detected by cantilever. These variations are used to create spatial mappings generated by subsurface and near-surface features/defects. To realize these efforts requires a way to combine scanning probe microscopy hardware, functional electronics and its integration into field programmable gate arrays for simultaneous generation and detection of multiple harmonics.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.