基于超景深算法的圆偏场瞬时光弹相移法拼接测量应用研究

Research on the application of circular off-field instantaneous photoelastic phaseshift splicing measurement based on ultra-depth of field algorithm

针对碳化硅晶圆片的应力双折射现象,实时应力检测过程中需要将待测碳化硅晶圆片沿切边方向旋转一个适当角度,以突出微管和位错的位置。然而,高倍率显微检测系统的景深较小,当碳化硅晶圆片倾斜时,大尺寸晶圆可能无法完全处于景深范围内,导致虚焦现象。虚焦现象对应力值影响不大,但会降低微管和位错的清晰度,甚至导致较小的微管在虚焦测量结果中消失。为了解决这个问题,提出了使用超景深合成算法对测量结果进行超景深融合。同时,使用机动平台将不同测量结果进行拼接,合成全局聚焦的测量结果,从而更好地测量应力值。实验结果表明,通过这种方法,可以有效改善测量结果的可视化效果。

In view of the stress birefringence of silicon carbide wafers,it is necessary to rotate the silicon carbide wafers with an appropriate angle along the cutting direction to highlight the position of microtubules and dislocations during real-time stress detection.However,the depth of field of the high-power microscopic inspection system is small,and when the silicon carbide wafer is tilted,the large-size wafer may not be fully within the depth of field,resulting in diffusion of focus.Virtual focus has little effect on the stress value,but it can reduce the clarity of microtubules and dislocations,and even cause smaller microtubules to disappear in the virtual focus measurement results.In order to solve this problem,this paper proposes to use the ultra depth field synthesis algorithm to merge the measured results.At the same time,a mobile platform is used to combine different measurement results to synthesize the globally focused measurement results,so as to measure the stress value.Experimental results show that this method can effectively improve the visualization effect of measurement results.