A novel optical method for measuring the thin film stress
A novel optical method for measuring the thin film stress
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DOI：
10.1117/12.2069833
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发表时间：
2014-08
期刊：
影响因子：
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通讯作者：
Y. Chu;Kun-Huang Chen;Jing-Heng Chen;Hua-Ken Tseng;Yuxin Chang
中科院分区：
文献类型：
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作者：
Y. Chu;Kun-Huang Chen;Jing-Heng Chen;Hua-Ken Tseng;Yuxin Chang
本文提出了一种薄膜应力测量系统。通过沿光栅平面沿着向投影光栅施加恒定速度，可以使用CCD相机记录正弦波的一系列采样点。利用最小二乘正弦拟合算法提取优化后的外差莫尔信号的相位分布，进而获得被测柔性基板的表面轮廓。采用多项式拟合的方法描述基片的横截面曲线，估算出未涂覆和涂覆基片的曲率半径，并将这两个曲率半径代入修正后的Stoney公式，从而得到柔性基片的薄膜应力。由于引入了投影云纹法和外差干涉法，该方法具有高稳定性和高分辨率的特点。
This paper proposes a thin-film stress measurement system. By applying a constant velocity to the projection grating along the grating plane, a series of sampling points of the sinusoidal wave can be recorded using a CCD camera. The phase distribution of the optimized heterodyne moiré signal can be extracted by the least-squares sine fitting algorithm and then the surface profile of the tested flexible substrate can subsequently be acquired. Using polynomial fitting method to depict the cross-section curve of the substrate, estimating the resultant curvature radii of the uncoated and coated substrates, and substituting these two radii into the corrected Stoney formula, the thin-film stress of the flexible substrate can consequently be obtained. This method features high stability and high resolution due to the introduction of the projection moiré and heterodyne interferometry.