基于虚拟双差动共焦的快速表面轮廓测量方法

Fast surface profile measurement method based on virtual double differential confocal

针对传统共焦显微技术定焦过程中扫描速度和扫描精度无法兼顾的问题,提出了一种基于虚拟双差动共焦的快速表面轮廓测量方法。其将传统共焦响应曲线向前平移和向后平移指定量得到虚拟前焦和虚拟后焦信号;然后将虚拟前、后焦信号与原始共焦信号分别相减,并将相减结果做相加处理得到虚拟双差动曲线。虚拟双差动曲线具有大线性范围、高定焦灵敏度的特点,在大扫描间距情况下获取表面轮廓时,可实现样品表面轮廓的快速、高精度的定焦。仿真分析及实验结果表明,与传统差动共焦显微成像方法相比,虚拟双差动共焦表面轮廓测量方法可在保持高定焦精度的前提下,将几何形貌成像速度提高2倍以上。

Aiming at the problem that the scanning speed and scanning accuracy cannot be taken into account in the fixed focus process of traditional confocal microscopy, a fast surface profile measurement method based on virtual double differential confocal is proposed. This method shifts the traditional confocal response curve forward and backward by a specified amount to obtain virtual front focus and virtual back focus signals. Then the virtual front and back focus signals are subtracted from the original confocal signal respectively, and the subtraction results are added together to obtain a virtual double differential curve. The virtual double differential curve has the characteristics of large linear range and high fixed focus sensitivity. When the surface profile is acquired under the condition of large scanning distance, the rapid and high-precision fixed focus of the sample surface profile can be achieved. Simulation analysis and experimental results show that, compared with traditional differential confocal microscopy imaging methods, the virtual double-differential confocal surface profile measurement method can increase the imaging speed of geometric topography by more than 2 times while maintaining high precision and fixed focus.