超精密元件亚表面微纳缺陷声场激励扫描探针测量机理与方法

超精密元件亚表面缺陷检测是超精密加工过程质量保障的关键需求，也是微纳测量领域的前沿热点问题。当前普遍使用的基于超声波或电磁波的检测技术囿于衍射极限的影响，难以实现对微纳尺度，尤其纳米尺度亚表面缺陷的精确测量。本项目旨在研究适用于超精密元件亚表面缺陷纳米分辨率检测的声场激励扫描探针测量新方法，该方法同时融合了扫描探针显微测量高分辨率的优势和声学技术对内部结构探测能力的优势。针对现有声场激励扫描探针测量技术存在的探针-缺陷耦合机理不明确、三维表征能力差、缺陷辨识度低等难题，项目摈弃传统的“单点扫描探测”模式，代之以“空间调制感知”思想，通过揭示声场激励与扫描探针的空间耦合机理、发展声场激励条件下探针空间调制感知扫描控制策略、建立多域信息反演的亚表面缺陷高信噪比重构方法，力争实现对超精密元件亚表面微纳尺度缺陷三维形态特征的高精度测量与表征，为超精密加工过程的质量控制提供一种行之有效的检测新途径。

Accurate detection of subsurface defects for ultra-precision components is the key requirement of quality assurance in ultra-precision machining processes, and it is also a hot and advanced research topic in the field of micro/nano metrology. At present, the resolution of the widely used subsurface defect detection method, which utilizes the ultrasonic wave or light wave, is inevitably limited by the wave diffraction effect. So that it is difficult for this kind of method to achieve accurate measurement of micro and even nano-scale subsurface defects. The purpose of this project is to develop a new methodology called acoustic excitation scanning probe measurement technique for accurate characterization of nano-scale subsurface defects. This methodology combines the advantage of high resolution of the scanning probe microscopy with the advantage of internal structure detection capability of the acoustic measuring technique. Taking into considerations the problems existing in the conventional acoustic scanning probe measurement technique, including unclear probe-defect coupling mechanism, poor three-dimensional characterization capability and low defect identification rate, this project abandons the traditional mode of "single-point scanning" and replaces it by the idea of "space modulation perception". Through investigating the spatial coupling mechanism of the acoustic field excitation and the scanning probe, developing a modulation perception scanning control strategy for the probe under the condition of acoustic field excitation, as well as establishing a new reconstruction method with high signal-to-noise ratio based on multi-domain information fusion, this research would achieve high-precision characterization of three-dimensional morphological characteristics of subsurface nano-scale defects for ultra-precision components. The success of this research would provide an effective and novel measurement method for quality control of ultra-precision machining processes.