基于LSTM的矩形纳米光栅AFM图像复原方法

AFM image restoration method of rectangular nano grating based on LSTM

原子力显微镜(AFM)利用探针与待测物之间的交互作用力进行成像,通过获取矩形纳米光栅计量标准器具的高分辨率成像得到相关的几何量参数并进行标定,实现从标准计量器具到工作计量器具的量值传递。在AFM扫描过程中,由于针尖的影响作用,使得扫描所获图像是探针和样品共同作用的结果,而不是样品形貌的真实描述。针对这一现象,本文提出了一种基于长短期记忆网络(LSTM)的AFM图像复原方法,该方法对通过膨胀法获得的仿真图像各扫描行进行训练,进而获得适用于矩形纳米光栅AFM图像复原模型。实验结果表明,针对线宽20 nm,高40 nm的矩形纳米光栅,经过该方法复原后光栅线宽的相对误差为7.40%,相较于传统的复原方法进一步提高了测量准确度。

Atomic force microscope(AFM)uses the interaction force between the probe and the object to be measured to achieve imaging,and obtains the relevant geometric parameters through obtaining the high-resolution imaging of the rectangular nano grating measurement standard instrument and performs calibration,so as to realize the quantity transfer from standard measurement instrument to working measurement instrument.In the AFM scanning process,due to the influence of the needle tip,the scanned image is the result of the interaction of the probe and the sample,rather than a true description of the sample morphology.Aiming at this phenomenon,this paper proposes an AFM image restoration method based on long short-term memory(LSTM)network.This method trains the scan lines of the simulation image obtained with the expansion method,and then obtains the AFM image restoration model suitable for rectangular nano grating.Experiment results show that for a rectangular nano-grating with a line width of 20 nm and a height of 40 nm,the relative error of the grating line width after restoration with the proposed method is 7.40%,the proposed method further improves the measurement accuracy compared with the traditional restoration method.