基于多步相移拟合的显微红外光弹系统研制

Instrument development of micro-infrared photoelasticity based on multistep phase-shift fitting

半导体电子器件的内部应力信息对于分析器件失效和材料破坏十分重要。红外光弹可能成为半导体材料与器件内部应力实验分析的有效手段。本文面向半导体材料与器件内部应力的定量表征,以近红外激光为光源,围绕多步相移拟合图像分析方法,通过选择分析核心部件和开发自动控制装置,研制了显微红外光弹系统。本文将该系统用于表征硅材料的内部应力场,并将分析结果与理论值和六步相移法计算结果进行对比,验证了所研制系统的可靠性,并展示了基于多步相移配合拟合识别的图像分析方法,相比已有技术对于分析因应力小或样品薄导致无整数级条纹出现的光弹图像具有较高的分析精度。

The internal stress of semiconductor electronic device is important for analyzing device failure and damage.Infrared photoelasticity may be an effective method for the internal stress analysis in semiconductor material and device.For the quantitative characterization of the internal stress of semiconductor,this work proposed a micro-infrared photoelasticity system.In this system,a near-infrared laser was used as the light source,and the multistep phase-shift fitting method was applied for image analysis.The system was utilized to characterize the internal stress of the silicon sample,the analyzing results achieved by the multistep phase-shift fitting method were compared with the theoretical values and the results based on the six-step phase-shift method,which verified the reliability of the developed system.It was also showed that the accuracy of stress analysis based on multistep phase-shift fitting method was much higher than other existing techniques,testifying that the system developed in this work was suitable to analyze the semiconductor structures with small stress level but large gradient or thin thickness.