Super-Resolution Optical Material Characterization

超分辨率光学材料表征

• 批准号: 2131486
• 负责人: Kevin Webb
• 金额: $ 40.75万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2131486&HistoricalAwards=false
• 关键词: Super; Resolution; Optical; Material; Characterization

This project entails the study of a means to determine information about object features at nanometer length scales, and in situations where the environment does not allow direct imaging of the object, using laser light. The approach is based on relative motion between a structured illumination pattern, formed from coherent light, and the object or material system, where either the light or the object is scanned in small precise spatial steps. To date, because the achievable resolution is generally limited to about one half of the optical wavelength without prior information, the approach in technology to improve spatial resolution or optical memory capacity has been to reduce the wavelength. This faces increasing challenges in moving to shorter wavelengths. On the other hand, the use of relative motion of a sample with a spatially varying optical intensity provides information about the sample that can be used for super-resolution imaging of features far smaller than the wavelength. Consequently, it should become possible to detect small structures of importance in the semiconductor industry and in microscopy. Furthermore, a suite of material inspection and imaging situations have significant background clutter, exacerbating the challenges. For example, it is currently difficult or impossible to detect small defects in the three-dimensional semiconductor processing steps used in building vertical solid-state memory, with multi-billion-dollar market ramifications. With laser inspection following the deposition of films, random scatter due to material roughness produces speckle, and this seemingly worsens the situation. During this project, an inspection and imaging method for extracting information about such defects and other objects by using speckle is being developed. More broadly, the approach enables a means to image objects hidden in a randomly scattering environment such as fog or biological tissue using light. The associated research is forming the basis of theses for two Ph.D. students, and the project involves undergraduate research students. A mathematical learning module is being created for junior high school students.Existing optical inspection methods are incapable of adequately detecting small defects in three-dimensional semiconductor structures like those in vertical memory. This project offers a path to finding such defects through two key objectives: (i) Numerical modeling to develop sensing and imaging with relative field motion; and (ii) Evaluative application-oriented experiments. Simulations with background laser beam interference fringes and random speckle fields are being used to investigate the relationship between far-subwavelength material geometric variables and the measured intensity as a function of relative position change, to provide a physical forward model for cost-function-based inversion, and to aid in the design of experiments. Two types of coherent optical sensing experiments are being investigated to illustrate technology applications with relative motion between an object of interest (to be characterized) and the background field. One involves speckle generated from a randomly scattering medium and statistical extraction of the relevant features. Another utilizes membrane films translated through interference fringes, with the use of a forward model to determine the associated parameters.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.

该项目需要研究一种在纳米尺度上确定物体特征信息的方法，以及在环境不允许使用激光直接成像物体的情况下。该方法基于由相干光形成的结构化照明模式与物体或材料系统之间的相对运动，其中光或物体以精确的小空间步骤进行扫描。迄今为止，由于可实现的分辨率通常被限制在光波长的一半左右，没有事先的信息，技术上提高空间分辨率或光存储容量的方法一直是减少波长。这在向短波长的移动中面临着越来越大的挑战。另一方面，利用具有空间变化光强的样品的相对运动提供了关于样品的信息，可用于远小于波长的特征的超分辨率成像。因此，它应该成为可能，以检测在半导体工业和显微镜中的重要的小结构。此外，一系列材料检测和成像情况具有明显的背景杂波，加剧了挑战。例如，目前很难或不可能检测到用于构建垂直固态存储器的三维半导体加工步骤中的小缺陷，这将带来数十亿美元的市场影响。在薄膜沉积后进行激光检查时，由于材料粗糙度而产生的随机散射会产生斑点，这似乎使情况恶化。在本项目中，正在开发一种利用斑点提取此类缺陷和其他物体信息的检测和成像方法。更广泛地说，该方法可以利用光对隐藏在随机散射环境（如雾或生物组织）中的物体进行成像。相关研究是两名博士生论文的基础，该项目涉及本科生研究生。正在为初中生创建一个数学学习模块。现有的光学检测方法无法充分检测出三维半导体结构（如垂直存储器）中的小缺陷。本项目通过两个关键目标为发现这些缺陷提供了途径：(i)数值模拟以发展具有相对场运动的传感和成像；（二）评价应用实验。利用背景激光干涉条纹和随机散斑场模拟，研究远亚波长材料几何变量与测量强度作为相对位置变化的函数之间的关系，为基于成本函数的反演提供物理正演模型，并为实验设计提供帮助。两种类型的相干光学传感实验正在进行研究，以说明在感兴趣的物体（待表征）和背景场之间相对运动的技术应用。其中一个涉及随机散射介质产生的斑点和相关特征的统计提取。另一种利用膜膜通过干涉条纹翻译，使用正演模型来确定相关参数。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。